Java/Data Type/Date Calculation

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Adds a number of days to a date returning a new object.

  
import java.util.Calendar;
import java.util.Date;
/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


/**
 * <p>A suite of utilities surrounding the use of the
 * {@link java.util.Calendar} and {@link java.util.Date} object.</p>
 * 
 * <p>DateUtils contains a lot of common methods considering manipulations
 * of Dates or Calendars. Some methods require some extra explanation.
 * The truncate and round methods could be considered the Math.floor(),
 * Math.ceil() or Math.round versions for dates
 * This way date-fields will be ignored in bottom-up order.
 * As a complement to these methods we"ve introduced some fragment-methods.
 * With these methods the Date-fields will be ignored in top-down order.
 * Since a date without a year is not a valid date, you have to decide in what
 * kind of date-field you want your result, for instance milliseconds or days.
 * </p>
 *   
 *   
 *
 * @author 
 * @author Phil Steitz
 * @author Robert Scholte
 * @since 2.0
 * @version $Id: DateUtils.java 634096 2008-03-06 00:58:11Z niallp $
 */
public class Main {

  //-----------------------------------------------------------------------
  /**
   * Adds a number of days to a date returning a new object.
   * The original date object is unchanged.
   *
   * @param date  the date, not null
   * @param amount  the amount to add, may be negative
   * @return the new date object with the amount added
   * @throws IllegalArgumentException if the date is null
   */
  public static Date addDays(Date date, int amount) {
      return add(date, Calendar.DAY_OF_MONTH, amount);
  }
  //-----------------------------------------------------------------------
  /**
   * Adds to a date returning a new object.
   * The original date object is unchanged.
   *
   * @param date  the date, not null
   * @param calendarField  the calendar field to add to
   * @param amount  the amount to add, may be negative
   * @return the new date object with the amount added
   * @throws IllegalArgumentException if the date is null
   */
  private static Date add(Date date, int calendarField, int amount) {
      if (date == null) {
          throw new IllegalArgumentException("The date must not be null");
      }
      Calendar c = Calendar.getInstance();
      c.setTime(date);
      c.add(calendarField, amount);
      return c.getTime();
  }
}





Adds a number of hours to a date returning a new object.

  
import java.util.Calendar;
import java.util.Date;
/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


/**
 * <p>A suite of utilities surrounding the use of the
 * {@link java.util.Calendar} and {@link java.util.Date} object.</p>
 * 
 * <p>DateUtils contains a lot of common methods considering manipulations
 * of Dates or Calendars. Some methods require some extra explanation.
 * The truncate and round methods could be considered the Math.floor(),
 * Math.ceil() or Math.round versions for dates
 * This way date-fields will be ignored in bottom-up order.
 * As a complement to these methods we"ve introduced some fragment-methods.
 * With these methods the Date-fields will be ignored in top-down order.
 * Since a date without a year is not a valid date, you have to decide in what
 * kind of date-field you want your result, for instance milliseconds or days.
 * </p>
 *   
 *   
 *
 * @author 
 * @author Phil Steitz
 * @author Robert Scholte
 * @since 2.0
 * @version $Id: DateUtils.java 634096 2008-03-06 00:58:11Z niallp $
 */
public class Main {

  //-----------------------------------------------------------------------
  /**
   * Adds a number of hours to a date returning a new object.
   * The original date object is unchanged.
   *
   * @param date  the date, not null
   * @param amount  the amount to add, may be negative
   * @return the new date object with the amount added
   * @throws IllegalArgumentException if the date is null
   */
  public static Date addHours(Date date, int amount) {
      return add(date, Calendar.HOUR_OF_DAY, amount);
  }
  //-----------------------------------------------------------------------
  /**
   * Adds to a date returning a new object.
   * The original date object is unchanged.
   *
   * @param date  the date, not null
   * @param calendarField  the calendar field to add to
   * @param amount  the amount to add, may be negative
   * @return the new date object with the amount added
   * @throws IllegalArgumentException if the date is null
   */
  private static Date add(Date date, int calendarField, int amount) {
      if (date == null) {
          throw new IllegalArgumentException("The date must not be null");
      }
      Calendar c = Calendar.getInstance();
      c.setTime(date);
      c.add(calendarField, amount);
      return c.getTime();
  }
}





Adds a number of milliseconds to a date returning a new object.

  
import java.util.Calendar;
import java.util.Date;
/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


/**
 * <p>A suite of utilities surrounding the use of the
 * {@link java.util.Calendar} and {@link java.util.Date} object.</p>
 * 
 * <p>DateUtils contains a lot of common methods considering manipulations
 * of Dates or Calendars. Some methods require some extra explanation.
 * The truncate and round methods could be considered the Math.floor(),
 * Math.ceil() or Math.round versions for dates
 * This way date-fields will be ignored in bottom-up order.
 * As a complement to these methods we"ve introduced some fragment-methods.
 * With these methods the Date-fields will be ignored in top-down order.
 * Since a date without a year is not a valid date, you have to decide in what
 * kind of date-field you want your result, for instance milliseconds or days.
 * </p>
 *   
 *   
 *
 * @author 
 * @author Phil Steitz
 * @author Robert Scholte
 * @since 2.0
 * @version $Id: DateUtils.java 634096 2008-03-06 00:58:11Z niallp $
 */
public class Main {
  //-----------------------------------------------------------------------
  /**
   * Adds a number of milliseconds to a date returning a new object.
   * The original date object is unchanged.
   *
   * @param date  the date, not null
   * @param amount  the amount to add, may be negative
   * @return the new date object with the amount added
   * @throws IllegalArgumentException if the date is null
   */
  public static Date addMilliseconds(Date date, int amount) {
      return add(date, Calendar.MILLISECOND, amount);
  }
  //-----------------------------------------------------------------------
  /**
   * Adds to a date returning a new object.
   * The original date object is unchanged.
   *
   * @param date  the date, not null
   * @param calendarField  the calendar field to add to
   * @param amount  the amount to add, may be negative
   * @return the new date object with the amount added
   * @throws IllegalArgumentException if the date is null
   */
  private static Date add(Date date, int calendarField, int amount) {
      if (date == null) {
          throw new IllegalArgumentException("The date must not be null");
      }
      Calendar c = Calendar.getInstance();
      c.setTime(date);
      c.add(calendarField, amount);
      return c.getTime();
  }
}





Adds a number of minutes to a date returning a new object.

  
import java.util.Calendar;
import java.util.Date;
/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


/**
 * <p>A suite of utilities surrounding the use of the
 * {@link java.util.Calendar} and {@link java.util.Date} object.</p>
 * 
 * <p>DateUtils contains a lot of common methods considering manipulations
 * of Dates or Calendars. Some methods require some extra explanation.
 * The truncate and round methods could be considered the Math.floor(),
 * Math.ceil() or Math.round versions for dates
 * This way date-fields will be ignored in bottom-up order.
 * As a complement to these methods we"ve introduced some fragment-methods.
 * With these methods the Date-fields will be ignored in top-down order.
 * Since a date without a year is not a valid date, you have to decide in what
 * kind of date-field you want your result, for instance milliseconds or days.
 * </p>
 *   
 *   
 *
 * @author 
 * @author Phil Steitz
 * @author Robert Scholte
 * @since 2.0
 * @version $Id: DateUtils.java 634096 2008-03-06 00:58:11Z niallp $
 */
public class Main {

  //-----------------------------------------------------------------------
  /**
   * Adds a number of minutes to a date returning a new object.
   * The original date object is unchanged.
   *
   * @param date  the date, not null
   * @param amount  the amount to add, may be negative
   * @return the new date object with the amount added
   * @throws IllegalArgumentException if the date is null
   */
  public static Date addMinutes(Date date, int amount) {
      return add(date, Calendar.MINUTE, amount);
  }
  //-----------------------------------------------------------------------
  /**
   * Adds to a date returning a new object.
   * The original date object is unchanged.
   *
   * @param date  the date, not null
   * @param calendarField  the calendar field to add to
   * @param amount  the amount to add, may be negative
   * @return the new date object with the amount added
   * @throws IllegalArgumentException if the date is null
   */
  private static Date add(Date date, int calendarField, int amount) {
      if (date == null) {
          throw new IllegalArgumentException("The date must not be null");
      }
      Calendar c = Calendar.getInstance();
      c.setTime(date);
      c.add(calendarField, amount);
      return c.getTime();
  }
}





Adds a number of months to a date returning a new object.

  
import java.math.BigDecimal;
import java.math.BigInteger;
import java.text.ParseException;
import java.text.ParsePosition;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


/**
 * <p>A suite of utilities surrounding the use of the
 * {@link java.util.Calendar} and {@link java.util.Date} object.</p>
 * 
 * <p>DateUtils contains a lot of common methods considering manipulations
 * of Dates or Calendars. Some methods require some extra explanation.
 * The truncate and round methods could be considered the Math.floor(),
 * Math.ceil() or Math.round versions for dates
 * This way date-fields will be ignored in bottom-up order.
 * As a complement to these methods we"ve introduced some fragment-methods.
 * With these methods the Date-fields will be ignored in top-down order.
 * Since a date without a year is not a valid date, you have to decide in what
 * kind of date-field you want your result, for instance milliseconds or days.
 * </p>
 *   
 *   
 *
 * @author 
 * @author Phil Steitz
 * @author Robert Scholte
 * @since 2.0
 * @version $Id: DateUtils.java 634096 2008-03-06 00:58:11Z niallp $
 */
public class Main {
  //-----------------------------------------------------------------------
  /**
   * Adds a number of months to a date returning a new object.
   * The original date object is unchanged.
   *
   * @param date  the date, not null
   * @param amount  the amount to add, may be negative
   * @return the new date object with the amount added
   * @throws IllegalArgumentException if the date is null
   */
  public static Date addMonths(Date date, int amount) {
      return add(date, Calendar.MONTH, amount);
  }
  //-----------------------------------------------------------------------
  /**
   * Adds to a date returning a new object.
   * The original date object is unchanged.
   *
   * @param date  the date, not null
   * @param calendarField  the calendar field to add to
   * @param amount  the amount to add, may be negative
   * @return the new date object with the amount added
   * @throws IllegalArgumentException if the date is null
   */
  private static Date add(Date date, int calendarField, int amount) {
      if (date == null) {
          throw new IllegalArgumentException("The date must not be null");
      }
      Calendar c = Calendar.getInstance();
      c.setTime(date);
      c.add(calendarField, amount);
      return c.getTime();
  }
}





Adds a number of seconds to a date returning a new object.

  
import java.util.Calendar;
import java.util.Date;
/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


/**
 * <p>A suite of utilities surrounding the use of the
 * {@link java.util.Calendar} and {@link java.util.Date} object.</p>
 * 
 * <p>DateUtils contains a lot of common methods considering manipulations
 * of Dates or Calendars. Some methods require some extra explanation.
 * The truncate and round methods could be considered the Math.floor(),
 * Math.ceil() or Math.round versions for dates
 * This way date-fields will be ignored in bottom-up order.
 * As a complement to these methods we"ve introduced some fragment-methods.
 * With these methods the Date-fields will be ignored in top-down order.
 * Since a date without a year is not a valid date, you have to decide in what
 * kind of date-field you want your result, for instance milliseconds or days.
 * </p>
 *   
 *   
 *
 * @author 
 * @author Phil Steitz
 * @author Robert Scholte
 * @since 2.0
 * @version $Id: DateUtils.java 634096 2008-03-06 00:58:11Z niallp $
 */
public class Main {
  //-----------------------------------------------------------------------
  /**
   * Adds a number of seconds to a date returning a new object.
   * The original date object is unchanged.
   *
   * @param date  the date, not null
   * @param amount  the amount to add, may be negative
   * @return the new date object with the amount added
   * @throws IllegalArgumentException if the date is null
   */
  public static Date addSeconds(Date date, int amount) {
      return add(date, Calendar.SECOND, amount);
  }
  //-----------------------------------------------------------------------
  /**
   * Adds to a date returning a new object.
   * The original date object is unchanged.
   *
   * @param date  the date, not null
   * @param calendarField  the calendar field to add to
   * @param amount  the amount to add, may be negative
   * @return the new date object with the amount added
   * @throws IllegalArgumentException if the date is null
   */
  private static Date add(Date date, int calendarField, int amount) {
      if (date == null) {
          throw new IllegalArgumentException("The date must not be null");
      }
      Calendar c = Calendar.getInstance();
      c.setTime(date);
      c.add(calendarField, amount);
      return c.getTime();
  }
}





Adds a number of weeks to a date returning a new object.

  
import java.util.Calendar;
import java.util.Date;
/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


/**
 * <p>A suite of utilities surrounding the use of the
 * {@link java.util.Calendar} and {@link java.util.Date} object.</p>
 * 
 * <p>DateUtils contains a lot of common methods considering manipulations
 * of Dates or Calendars. Some methods require some extra explanation.
 * The truncate and round methods could be considered the Math.floor(),
 * Math.ceil() or Math.round versions for dates
 * This way date-fields will be ignored in bottom-up order.
 * As a complement to these methods we"ve introduced some fragment-methods.
 * With these methods the Date-fields will be ignored in top-down order.
 * Since a date without a year is not a valid date, you have to decide in what
 * kind of date-field you want your result, for instance milliseconds or days.
 * </p>
 *   
 *   
 *
 * @author 
 * @author Phil Steitz
 * @author Robert Scholte
 * @since 2.0
 * @version $Id: DateUtils.java 634096 2008-03-06 00:58:11Z niallp $
 */
public class Main {

  //-----------------------------------------------------------------------
  /**
   * Adds a number of weeks to a date returning a new object.
   * The original date object is unchanged.
   *
   * @param date  the date, not null
   * @param amount  the amount to add, may be negative
   * @return the new date object with the amount added
   * @throws IllegalArgumentException if the date is null
   */
  public static Date addWeeks(Date date, int amount) {
      return add(date, Calendar.WEEK_OF_YEAR, amount);
  }
  //-----------------------------------------------------------------------
  /**
   * Adds to a date returning a new object.
   * The original date object is unchanged.
   *
   * @param date  the date, not null
   * @param calendarField  the calendar field to add to
   * @param amount  the amount to add, may be negative
   * @return the new date object with the amount added
   * @throws IllegalArgumentException if the date is null
   */
  private static Date add(Date date, int calendarField, int amount) {
      if (date == null) {
          throw new IllegalArgumentException("The date must not be null");
      }
      Calendar c = Calendar.getInstance();
      c.setTime(date);
      c.add(calendarField, amount);
      return c.getTime();
  }
}





Adds a number of years to a date returning a new object.

  
import java.math.BigDecimal;
import java.math.BigInteger;
import java.text.ParseException;
import java.text.ParsePosition;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


/**
 * <p>A suite of utilities surrounding the use of the
 * {@link java.util.Calendar} and {@link java.util.Date} object.</p>
 * 
 * <p>DateUtils contains a lot of common methods considering manipulations
 * of Dates or Calendars. Some methods require some extra explanation.
 * The truncate and round methods could be considered the Math.floor(),
 * Math.ceil() or Math.round versions for dates
 * This way date-fields will be ignored in bottom-up order.
 * As a complement to these methods we"ve introduced some fragment-methods.
 * With these methods the Date-fields will be ignored in top-down order.
 * Since a date without a year is not a valid date, you have to decide in what
 * kind of date-field you want your result, for instance milliseconds or days.
 * </p>
 *   
 *   
 *
 * @author 
 * @author Phil Steitz
 * @author Robert Scholte
 * @since 2.0
 * @version $Id: DateUtils.java 634096 2008-03-06 00:58:11Z niallp $
 */
public class Main {
  //-----------------------------------------------------------------------
  /**
   * Adds a number of years to a date returning a new object.
   * The original date object is unchanged.
   *
   * @param date  the date, not null
   * @param amount  the amount to add, may be negative
   * @return the new date object with the amount added
   * @throws IllegalArgumentException if the date is null
   */
  public static Date addYears(Date date, int amount) {
      return add(date, Calendar.YEAR, amount);
  }
  //-----------------------------------------------------------------------
  /**
   * Adds to a date returning a new object.
   * The original date object is unchanged.
   *
   * @param date  the date, not null
   * @param calendarField  the calendar field to add to
   * @param amount  the amount to add, may be negative
   * @return the new date object with the amount added
   * @throws IllegalArgumentException if the date is null
   */
  private static Date add(Date date, int calendarField, int amount) {
      if (date == null) {
          throw new IllegalArgumentException("The date must not be null");
      }
      Calendar c = Calendar.getInstance();
      c.setTime(date);
      c.add(calendarField, amount);
      return c.getTime();
  }
}





Calculate Holidays

  
//** Copyright Statement ***************************************************
//The Salmon Open Framework for Internet Applications (SOFIA)
// Copyright (C) 1999 - 2002, Salmon LLC
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License version 2
// as published by the Free Software Foundation;
// 
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
// 
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
// 
// For more information please visit http://www.salmonllc.ru
//** End Copyright Statement ***************************************************
//
//
//    Author: Gregory N. Mirsky
//    Updated: John D. Mitchell
//    Version 1.02
//
  
import java.util.Calendar;

public class Holidays
    {
//*********************************
// Miscellaneous other holidays are left as an exercise for the reader.
//
// public static Date QuebecCivicHoliday (int nYear)
// {
//  // 03 January YYYY
// }
//
// public static Date AshWednesday (int nYear)
// {
//  // 42 days before easter...
// }
//
// public static Date PalmSunday (int nYear)
// {
//  // Sunday before Easter Sunday...
// }
//
// public static Date MaundayThursday (int nYear)
// {
//  // Thursday before Easter...
// }
//
//  public static Date RoshHashanah(int nYear)
// {
//  Source: William H. Jefferys, Department of Astronomy, University of
//  Texas Austin, TX 78712 
//
//         http://quasar.as.utexas.edu
//
//  First, calculate the Golden Number G. This is fundamental to the
//  calculation of both the date of Easter and the Date of Rosh Hashanah. 
//  It is intimately connected with the Metonic Cycle. For any year Y, the
//  Golden Number is defined as 
//
//  G = Remainder(Y|19) + 1. Don"t forget to add the 1!!!
//
//  The following rules are also due to John Horton Conway, of Princeton
//  University. In the Gregorian year Y of the Common Era, Rosh Hashanah
//  normally falls on September N, where
//
//  N + fraction = {[Y/100] - [Y/400] - 2} +
//  765433/492480*Remainder(12G|19) + Remainder(Y|4)/4 - (313Y+89081)/98496
//
//  Here, G is the Golden Number, and * means multiply. However, if certain
//  conditions are satisfied, Rosh Hashanah is postponed by one or even two
//  days, as follows: 
//
//      ***Postponement rules***
//
//  1.If the day calculated above is a Sunday, Wednesday, or Friday, Rosh
//  Hashanah falls on the next day (Monday, Thursday or Saturday,
//  respectively).
//
//  2.If the calculated day is a Monday, and if the fraction is greater
//  than or equal to 23269/25920, and if Remainder(12G|19) is greater than
//  11, Rosh Hashanah falls on the next day, a Tuesday.
//
//  3.If it is a Tuesday, and if the fraction is greater than or equal to
//  1367/2160, and if Remainder(12G|19) is greater than 6, Rosh Hashanah
//  falls two days later, on Thursday (NOT WEDNESDAY!!).
// }
//
//  public static Date Passover(int nYear)
// {
//  Source: William H. Jefferys, Department of Astronomy, University of
//  Texas Austin, TX 78712
//
//         http://quasar.as.utexas.edu
//
//  Once you have determined the date of Rosh Hashanah, it is easy to
//  calculate the date of Passover in the same (Gregorian or Julian)
//  year. Let M = the number of days from September 6 to Rosh Hashanah.
//  In the example for 1996, M=September 14-September 6 = 8 days.
//
//  Count M days from March 27. That is the date of Passover. It actually
//  begins at sundown on the previous evening. In the example for 1996, 8
//  days after March 27 is April 4 (there are 31 days in March), so
//  Passover begins at sundown on April 3.
// }
//
// public static Date DominionDay (int nYear)
// {
//  // 01 July YYYY
// }
//
// public static Date BoxingDay (int nYear)
//  {
//  // Day after Christmas, December 26th...
//  }
//
//*********************************************

   
    
public static java.util.Calendar AbrahamLincolnsBirthday (int nYear){
  int nMonth = 1; // February
  // February 12th
  java.util.Calendar cal = java.util.Calendar.getInstance();
  cal.set(nYear, nMonth, 12); 
  return cal;
}
public static java.util.Calendar ChristmasDay (int nYear){
  int nMonth = 11; // Decmeber
  // December 25th
  java.util.Calendar cal = java.util.Calendar.getInstance();
  cal.set(nYear, nMonth, 25);
  return cal;
}
    public static java.util.Calendar ChristmasDayObserved (int nYear)
  {
  int nX;
  int nMonth = 11; // December
  java.util.Calendar cal;
  cal = java.util.Calendar.getInstance();
  cal.set(nYear, nMonth, 25);
  nX = cal.get(Calendar.DAY_OF_WEEK);
  switch(nX)
      {
      case 0 : {// Sunday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 26);
      return cal;
      }
      case 1 : // Monday
      case 2 : // Tuesday
      case 3 : // Wednesday
      case 4 : // Thrusday
      case 5 :{ // Friday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 25);
      return cal;
      }
      default :{
    // Saturday
      cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 24);
      return cal;
      }
    }
}
    public static java.util.Calendar ColumbusDayObserved (int nYear)
  {
  // Second Monday in October
  int nX;
  int nMonth = 9; // October 
  java.util.Calendar cal;
  cal = java.util.Calendar.getInstance();
  cal.set(nYear, nMonth, 1);
  nX = cal.get(Calendar.DAY_OF_WEEK);
  switch(nX)
      {
      case 0 : {// Sunday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 9);
      return cal;
      }
    case 1 : {// Monday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 15);
      return cal;
      }
      case 2 : // Tuesday
      {
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 14);
      return cal;
      }
      case 3 : // Wednesday
    {
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 13);
      return cal;
      }
      case 4 : // Thrusday
    {
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 12);
      return cal;
      }
      case 5 : // Friday
    {
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 11);
      return cal;
      }
      default : // Saturday
    {
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 10);
      return cal;
      }
      }
  }
    public static java.util.Calendar EasterMonday (int nYear)
  {
  int nEasterMonth = 0;
  int nEasterDay   = 0;
  int nMonthMarch  = 2; // March
  int nMonthApril  = 3; // April
  java.util.Calendar cEasterSunday = EasterSunday(nYear);
  nEasterMonth = cEasterSunday.get(Calendar.MONTH);
  nEasterDay = cEasterSunday.get(Calendar.DAY_OF_MONTH);
  if (nEasterMonth == nMonthMarch || nEasterDay == 31){
    java.util.Calendar cal = java.util.Calendar.getInstance();
    cal.set(nYear, nMonthApril, 1);
    return cal;
  }else{
    java.util.Calendar cal = java.util.Calendar.getInstance();
    cal.set(nYear, nEasterMonth, ++nEasterDay);
    return cal;
  }
}
    public static java.util.Calendar EasterSunday(int nYear)
  { 
/*  Calculate Easter Sunday
  Written by Gregory N. Mirsky
  Source: 2nd Edition by Peter Duffett-Smith. It was originally from
  Butcher"s Ecclesiastical Calendar, published in 1876. This
  algorithm has also been published in the 1922 book General
  Astronomy by Spencer Jones; in The Journal of the British
  Astronomical Association (Vol.88, page 91, December 1977); and in
  Astronomical Algorithms (1991) by Jean Meeus.
  This algorithm holds for any year in the Gregorian Calendar, which
  (of course) means years including and after 1583.
        a=year%19
        b=year/100
        c=year%100
        d=b/4
        e=b%4
        f=(b+8)/25
        g=(b-f+1)/3
        h=(19*a+b-d-g+15)%30
        i=c/4
        k=c%4
        l=(32+2*e+2*i-h-k)%7
        m=(a+11*h+22*l)/451
        Easter Month =(h+l-7*m+114)/31  [3=March, 4=April]
        p=(h+l-7*m+114)%31
        Easter Date=p+1     (date in Easter Month)
  Note: Integer truncation is already factored into the
  calculations. Using higher percision variables will cause
  inaccurate calculations. 
*/
  int nA      = 0;
  int nB      = 0;
  int nC      = 0;  
  int nD      = 0;
  int nE      = 0;
  int nF      = 0;
  int nG      = 0;
  int nH      = 0;
  int nI      = 0;
  int nK      = 0;
  int nL      = 0;
  int nM      = 0;
  int nP      = 0;
  int nEasterMonth  = 0;
  int nEasterDay    = 0;
  // Calculate Easter
  if (nYear < 1900) 
      { 
      // if year is in java format put it into standard
      // format for the calculation
      nYear += 1900; 
      }
  nA = nYear % 19;
  nB = nYear / 100;
  nC = nYear % 100;
  nD = nB / 4;
  nE = nB % 4;
  nF = (nB + 8) / 25;
  nG = (nB - nF + 1) / 3;
  nH = (19 * nA + nB - nD - nG + 15) % 30;
  nI = nC / 4;
  nK = nC % 4;
  nL = (32 + 2 * nE + 2 * nI - nH - nK) % 7;
  nM=  (nA + 11 * nH + 22 * nL) / 451;
  //  [3=March, 4=April]
  nEasterMonth = (nH + nL - 7 * nM + 114) / 31;
  --nEasterMonth;
  nP = (nH + nL - 7 * nM + 114) % 31;
  // Date in Easter Month.
  nEasterDay = nP + 1;
  // Uncorrect for our earlier correction.
  nYear -= 1900;
  // Populate the date object...
  java.util.Calendar cal = java.util.Calendar.getInstance();
  cal.set(nYear, nEasterMonth, nEasterDay);
  return cal;
  }
    public static java.util.Calendar GoodFridayObserved(int nYear)
  {
  // Get Easter Sunday and subtract two days
  int nEasterMonth  = 0;
  int nEasterDay    = 0;
  int nGoodFridayMonth  = 0;
  int nGoodFridayDay  = 0;
  java.util.Calendar cEasterSunday;
    
  cEasterSunday = EasterSunday(nYear);
  nEasterMonth = cEasterSunday.get(Calendar.MONTH);
  nEasterDay = cEasterSunday.get(Calendar.DAY_OF_MONTH);
  if (nEasterDay <= 3 && nEasterMonth == 3){ // Check if <= April 3rd
      
      switch(nEasterDay){
    case 3 : 
        nGoodFridayMonth = nEasterMonth - 1;
        nGoodFridayDay   = nEasterDay - 2;
        break;
    case 2 :
        nGoodFridayMonth = nEasterMonth - 1;
        nGoodFridayDay   = 31;
        break;
    case 1 :
        nGoodFridayMonth = nEasterMonth - 1;
        nGoodFridayDay   = 31;
        break;
    default:
        nGoodFridayMonth = nEasterMonth;
        nGoodFridayDay   = nEasterDay - 2;
    }
  }else{
      nGoodFridayMonth = nEasterMonth;
      nGoodFridayDay   = nEasterDay - 2;
  }
    java.util.Calendar cal = java.util.Calendar.getInstance();
  cal.set(nYear, nGoodFridayMonth, nGoodFridayDay);
  return cal;
}
public static java.util.Calendar Halloween (int nYear){
  int nMonth = 9;
  // October 31st
  java.util.Calendar cal = java.util.Calendar.getInstance();
  cal.set(nYear, nMonth, 31);
  return cal;
}
    public static java.util.Calendar IndependenceDay (int nYear)
  {
  int nMonth = 6; // July
  // July 4th
  java.util.Calendar cal = java.util.Calendar.getInstance();
  cal.set(nYear, nMonth, 4);
  return cal;
}
public static java.util.Calendar IndependenceDayObserved (int nYear){
  int nX;
  int nMonth = 6; // July
  
  java.util.Calendar cal = java.util.Calendar.getInstance();
  cal.set(nYear, nMonth, 4);
      
  nX = cal.get(Calendar.DAY_OF_WEEK);
  switch(nX){
      case 0 : // Sunday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 5);
      return cal;
    case 1 : // Monday
      case 2 : // Tuesday
      case 3 : // Wednesday
      case 4 : // Thrusday
      case 5 : // Friday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 4);
      return cal;
      default :
    // Saturday
      cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 3);
      return cal;
    }
}
public static java.util.Calendar LaborDayObserved (int nYear){
  // The first Monday in September
  int nX;
  int nMonth = 8; // September
  java.util.Calendar cal = java.util.Calendar.getInstance();
  cal.set(nYear, 9, 1);
      
  nX = cal.get(Calendar.DAY_OF_WEEK);
    
  switch(nX){
      case 0 : // Sunday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 2);
      return cal;
    case 1 : // Monday
      cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 7);
      return cal;
      case 2 : // Tuesday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 6);
      return cal;
      case 3 : // Wednesday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 5);
      return cal;
      case 4 : // Thrusday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 4);
      return cal;
      case 5 : // Friday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 3);
      return cal;
      default : // Saturday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 2);
      return cal;
    }
}
public java.util.Calendar MartinLutherKingObserved (int nYear){
  // Third Monday in January
  int nX;
  int nMonth = 0; // January
  java.util.Calendar cal;
  cal = java.util.Calendar.getInstance();
  cal.set(nYear, nMonth, 1);
  nX = cal.get(Calendar.DAY_OF_WEEK);
  
  switch(nX) {
    case 0 : {// Sunday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 16);
      return cal;
      }
    case 1 : {// Monday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 15);
      return cal;
      }
      case 2 : // Tuesday
      {
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 21);
      return cal;
      }
      case 3 : // Wednesday
    {
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 20);
      return cal;
      }
      case 4 : // Thrusday
    {
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 19);
      return cal;
      }
      case 5 : // Friday
    {
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 18);
      return cal;
      }
      default : // Saturday
    {
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 17);
      return cal;
      }
      
    }
}
public static java.util.Calendar MemorialDayObserved (int nYear){
  // Last Monday in May
  int nX;
  int nMonth = 4; //May
  java.util.Calendar cal = java.util.Calendar.getInstance();
  cal.set(nYear, nMonth, 31);
      
  nX = cal.get(Calendar.DAY_OF_WEEK);
  
  
  switch(nX){
     case 0 : // Sunday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 25);
      return cal;
    case 1 : // Monday
      cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 31);
      return cal;
      case 2 : // Tuesday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 30);
      return cal;
      case 3 : // Wednesday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 29);
      return cal;
      case 4 : // Thrusday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 28);
      return cal;
      case 5 : // Friday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 27);
      return cal;
      default : // Saturday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 26);
      return cal;
    
    }
}
public static java.util.Calendar  NewYearsDay (int nYear){
  // January 1st
  int nMonth = 0; // January
  java.util.Calendar cal = java.util.Calendar.getInstance();
  cal.set(nYear, nMonth, 1);
  
  return cal;
}
public static java.util.Calendar NewYearsDayObserved (int nYear){
  int nX;
  int nMonth = 0;     // January
  int nMonthDecember = 11;  // December
  
  java.util.Calendar cal = java.util.Calendar.getInstance();
  cal.set(nYear, nMonth, 1);
      
  nX = cal.get(Calendar.DAY_OF_WEEK);
    
  if (nYear > 1900)
      nYear -= 1900;
  switch(nX){
      case 0 : // Sunday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 2);
      return cal;
      case 1 : // Monday
      case 2 : // Tuesday
      case 3 : // Wednesday
      case 4 : // Thrusday
      case 5 : // Friday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 1);
      return cal;
      default :
    // Saturday, then observe on friday of previous year
      cal = java.util.Calendar.getInstance();
      cal.set(--nYear, nMonthDecember, 31);
      return cal;
    }
}
public static java.util.Calendar PresidentsDayObserved (int nYear){
  // Third Monday in February
  int nX;
  int nMonth = 1; // February
  java.util.Calendar cal = java.util.Calendar.getInstance();
  cal.set(nYear, nMonth, 1);
      
  nX = cal.get(Calendar.DAY_OF_WEEK);
  
  switch(nX){
     case 0 : {// Sunday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 16);
      return cal;
      }
    case 1 : {// Monday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 15);
      return cal;
      }
      case 2 : // Tuesday
      {
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 21);
      return cal;
      }
      case 3 : // Wednesday
    {
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 20);
      return cal;
      }
      case 4 : // Thrusday
    {
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 19);
      return cal;
      }
      case 5 : // Friday
    {
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 18);
      return cal;
      }
      default : // Saturday
    {
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 17);
      return cal;
      }
    }
}
public static java.util.Calendar ThanksgivingObserved(int nYear){
  int nX;
  int nMonth = 10; // November
  java.util.Calendar cal = java.util.Calendar.getInstance();
  cal.set(nYear, nMonth, 1);
      
  nX = cal.get(Calendar.DAY_OF_WEEK);
  switch(nX){
    
    case 0 : {// Sunday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 26);
      return cal;
      }
    case 1 : {// Monday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 25);
      return cal;
      }
      case 2 : // Tuesday
      {
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 24);
      return cal;
      }
      case 3 : // Wednesday
    {
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 23);
      return cal;
      }
      case 4 : // Thrusday
    {
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 22);
      return cal;
      }
      case 5 : // Friday
    {
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 28);
      return cal;
      }
      default : // Saturday
    {
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 27);
      return cal;
      }
    }
}
public static java.util.Calendar USElectionDay (int nYear){
  // First Tuesday in November
  int nX; 
  int nMonth = 10; // November
  java.util.Calendar cal = java.util.Calendar.getInstance();
  cal.set(nYear, nMonth, 1);
  nX = cal.get(Calendar.DAY_OF_WEEK);
  switch(nX){
      case 0 : {// Sunday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 3);
      return cal;
      }
    case 1 : {// Monday
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 2);
      return cal;
      }
      case 2 : // Tuesday
      {
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 1);
      return cal;
      }
      case 3 : // Wednesday
    {
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 7);
      return cal;
      }
      case 4 : // Thrusday
    {
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 6);
      return cal;
      }
      case 5 : // Friday
    {
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 5);
      return cal;
      }
      default : // Saturday
    {
        cal = java.util.Calendar.getInstance();
      cal.set(nYear, nMonth, 4);
      return cal;
      }
    }
}
public static java.util.Calendar ValentinesDay (int nYear){
  int nMonth = 1; // February
  // February 14th
  java.util.Calendar cal = java.util.Calendar.getInstance();
  cal.set(nYear, nMonth, 14);
  return cal;
}
public static java.util.Calendar VeteransDayObserved (int nYear){
  //November 11th
  int nMonth = 10; // November
  java.util.Calendar cal = java.util.Calendar.getInstance();
  cal.set(nYear, nMonth, 11);
  return cal;
}
public static String getClassInfo()
  {
  return ("Name: Holidays\r\n" +
    "Author: Gregory N. Mirsky\r\n" +
    "Updated: John D. Mitchell\r\n" +
    "Version 1.02\r\n" +
    "Copyright 1997, All rights reserved.");
  }
}





Checking date as String formatted by a date format

   

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
/**
 * Utility for checking date as String formatted by a date format.
 * By default, the date format u
 *
 * @see java.text.DateFormat
 */
public class DateUtils {
  public static final SimpleDateFormat DEFAULT_DATE_FORMAT = new SimpleDateFormat("yyyy.MM.dd HH:mm");
  private static DateFormat dateFormat = DEFAULT_DATE_FORMAT;
  private DateUtils() {
    // Instanceless class
  }
  /**
   * Returns the date from the given value parsed by the date format.
   */
  public static Date getDate(String yyyyMMdd) throws ParseException {
    synchronized (dateFormat) {
      return dateFormat.parse(yyyyMMdd);
    }
  }
  /**
   * Returns the Date as String formated by the date format.
   */
  public static String getStandardDate(Date date) {
    synchronized (dateFormat) {
      return dateFormat.format(date);
    }
  }
  /**
   * Sets the date format.
   */
  public static void setDateFormat(DateFormat dateFormat) {
    DateUtils.dateFormat = dateFormat;
  }
}





Checks if a calendar date is after today and within a number of days in the future

   

import java.util.Calendar;
import java.util.Date;
public class DateUtils {
    
    /**
     * <p>Checks if two dates are on the same day ignoring time.</p>
     * @param date1  the first date, not altered, not null
     * @param date2  the second date, not altered, not null
     * @return true if they represent the same day
     * @throws IllegalArgumentException if either date is <code>null</code>
     */
    public static boolean isSameDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isSameDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if two calendars represent the same day ignoring time.</p>
     * @param cal1  the first calendar, not altered, not null
     * @param cal2  the second calendar, not altered, not null
     * @return true if they represent the same day
     * @throws IllegalArgumentException if either calendar is <code>null</code>
     */
    public static boolean isSameDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        return (cal1.get(Calendar.ERA) == cal2.get(Calendar.ERA) &&
                cal1.get(Calendar.YEAR) == cal2.get(Calendar.YEAR) &&
                cal1.get(Calendar.DAY_OF_YEAR) == cal2.get(Calendar.DAY_OF_YEAR));
    }
    
    /**
     * <p>Checks if a date is today.</p>
     * @param date the date, not altered, not null.
     * @return true if the date is today.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isToday(Date date) {
        return isSameDay(date, Calendar.getInstance().getTime());
    }
    
    /**
     * <p>Checks if a calendar date is today.</p>
     * @param cal  the calendar, not altered, not null
     * @return true if cal date is today
     * @throws IllegalArgumentException if the calendar is <code>null</code>
     */
    public static boolean isToday(Calendar cal) {
        return isSameDay(cal, Calendar.getInstance());
    }
    
    /**
     * <p>Checks if the first date is before the second date ignoring time.</p>
     * @param date1 the first date, not altered, not null
     * @param date2 the second date, not altered, not null
     * @return true if the first date day is before the second date day.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isBeforeDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isBeforeDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if the first calendar date is before the second calendar date ignoring time.</p>
     * @param cal1 the first calendar, not altered, not null.
     * @param cal2 the second calendar, not altered, not null.
     * @return true if cal1 date is before cal2 date ignoring time.
     * @throws IllegalArgumentException if either of the calendars are <code>null</code>
     */
    public static boolean isBeforeDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        if (cal1.get(Calendar.ERA) < cal2.get(Calendar.ERA)) return true;
        if (cal1.get(Calendar.ERA) > cal2.get(Calendar.ERA)) return false;
        if (cal1.get(Calendar.YEAR) < cal2.get(Calendar.YEAR)) return true;
        if (cal1.get(Calendar.YEAR) > cal2.get(Calendar.YEAR)) return false;
        return cal1.get(Calendar.DAY_OF_YEAR) < cal2.get(Calendar.DAY_OF_YEAR);
    }
    
    /**
     * <p>Checks if the first date is after the second date ignoring time.</p>
     * @param date1 the first date, not altered, not null
     * @param date2 the second date, not altered, not null
     * @return true if the first date day is after the second date day.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isAfterDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isAfterDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if the first calendar date is after the second calendar date ignoring time.</p>
     * @param cal1 the first calendar, not altered, not null.
     * @param cal2 the second calendar, not altered, not null.
     * @return true if cal1 date is after cal2 date ignoring time.
     * @throws IllegalArgumentException if either of the calendars are <code>null</code>
     */
    public static boolean isAfterDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        if (cal1.get(Calendar.ERA) < cal2.get(Calendar.ERA)) return false;
        if (cal1.get(Calendar.ERA) > cal2.get(Calendar.ERA)) return true;
        if (cal1.get(Calendar.YEAR) < cal2.get(Calendar.YEAR)) return false;
        if (cal1.get(Calendar.YEAR) > cal2.get(Calendar.YEAR)) return true;
        return cal1.get(Calendar.DAY_OF_YEAR) > cal2.get(Calendar.DAY_OF_YEAR);
    }
    
    /**
     * <p>Checks if a date is after today and within a number of days in the future.</p>
     * @param date the date to check, not altered, not null.
     * @param days the number of days.
     * @return true if the date day is after today and within days in the future .
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isWithinDaysFuture(Date date, int days) {
        if (date == null) {
            throw new IllegalArgumentException("The date must not be null");
        }
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        return isWithinDaysFuture(cal, days);
    }
    
    /**
     * <p>Checks if a calendar date is after today and within a number of days in the future.</p>
     * @param cal the calendar, not altered, not null
     * @param days the number of days.
     * @return true if the calendar date day is after today and within days in the future .
     * @throws IllegalArgumentException if the calendar is <code>null</code>
     */
    public static boolean isWithinDaysFuture(Calendar cal, int days) {
        if (cal == null) {
            throw new IllegalArgumentException("The date must not be null");
        }
        Calendar today = Calendar.getInstance();
        Calendar future = Calendar.getInstance();
        future.add(Calendar.DAY_OF_YEAR, days);
        return (isAfterDay(cal, today) && ! isAfterDay(cal, future));
    }
    
    /** Returns the given date with the time set to the start of the day. */
    public static Date getStart(Date date) {
        return clearTime(date);
    }
    
    /** Returns the given date with the time values cleared. */
    public static Date clearTime(Date date) {
        if (date == null) {
            return null;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.set(Calendar.HOUR_OF_DAY, 0);
        c.set(Calendar.MINUTE, 0);
        c.set(Calendar.SECOND, 0);
        c.set(Calendar.MILLISECOND, 0);
        return c.getTime();
    }    
    /** Determines whether or not a date has any time values (hour, minute, 
     * seconds or millisecondsReturns the given date with the time values cleared. */
    /**
     * Determines whether or not a date has any time values.
     * @param date The date.
     * @return true iff the date is not null and any of the date"s hour, minute,
     * seconds or millisecond values are greater than zero.
     */
    public static boolean hasTime(Date date) {
        if (date == null) {
            return false;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        if (c.get(Calendar.HOUR_OF_DAY) > 0) {
            return true;
        }
        if (c.get(Calendar.MINUTE) > 0) {
            return true;
        }
        if (c.get(Calendar.SECOND) > 0) {
            return true;
        }
        if (c.get(Calendar.MILLISECOND) > 0) {
            return true;
        }
        return false;
    }
    /** Returns the given date with time set to the end of the day */
    public static Date getEnd(Date date) {
        if (date == null) {
            return null;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.set(Calendar.HOUR_OF_DAY, 23);
        c.set(Calendar.MINUTE, 59);
        c.set(Calendar.SECOND, 59);
        c.set(Calendar.MILLISECOND, 999);
        return c.getTime();
    }
    /** 
     * Returns the maximum of two dates. A null date is treated as being less
     * than any non-null date. 
     */
    public static Date max(Date d1, Date d2) {
        if (d1 == null && d2 == null) return null;
        if (d1 == null) return d2;
        if (d2 == null) return d1;
        return (d1.after(d2)) ? d1 : d2;
    }
    
    /** 
     * Returns the minimum of two dates. A null date is treated as being greater
     * than any non-null date. 
     */
    public static Date min(Date d1, Date d2) {
        if (d1 == null && d2 == null) return null;
        if (d1 == null) return d2;
        if (d2 == null) return d1;
        return (d1.before(d2)) ? d1 : d2;
    }
    /** The maximum date possible. */
    public static Date MAX_DATE = new Date(Long.MAX_VALUE);
    
}





Checks if a calendar date is today

   

import java.util.Calendar;
import java.util.Date;
public class DateUtils {
    
    /**
     * <p>Checks if two dates are on the same day ignoring time.</p>
     * @param date1  the first date, not altered, not null
     * @param date2  the second date, not altered, not null
     * @return true if they represent the same day
     * @throws IllegalArgumentException if either date is <code>null</code>
     */
    public static boolean isSameDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isSameDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if two calendars represent the same day ignoring time.</p>
     * @param cal1  the first calendar, not altered, not null
     * @param cal2  the second calendar, not altered, not null
     * @return true if they represent the same day
     * @throws IllegalArgumentException if either calendar is <code>null</code>
     */
    public static boolean isSameDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        return (cal1.get(Calendar.ERA) == cal2.get(Calendar.ERA) &&
                cal1.get(Calendar.YEAR) == cal2.get(Calendar.YEAR) &&
                cal1.get(Calendar.DAY_OF_YEAR) == cal2.get(Calendar.DAY_OF_YEAR));
    }
    
    /**
     * <p>Checks if a date is today.</p>
     * @param date the date, not altered, not null.
     * @return true if the date is today.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isToday(Date date) {
        return isSameDay(date, Calendar.getInstance().getTime());
    }
    
    /**
     * <p>Checks if a calendar date is today.</p>
     * @param cal  the calendar, not altered, not null
     * @return true if cal date is today
     * @throws IllegalArgumentException if the calendar is <code>null</code>
     */
    public static boolean isToday(Calendar cal) {
        return isSameDay(cal, Calendar.getInstance());
    }
    
    /**
     * <p>Checks if the first date is before the second date ignoring time.</p>
     * @param date1 the first date, not altered, not null
     * @param date2 the second date, not altered, not null
     * @return true if the first date day is before the second date day.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isBeforeDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isBeforeDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if the first calendar date is before the second calendar date ignoring time.</p>
     * @param cal1 the first calendar, not altered, not null.
     * @param cal2 the second calendar, not altered, not null.
     * @return true if cal1 date is before cal2 date ignoring time.
     * @throws IllegalArgumentException if either of the calendars are <code>null</code>
     */
    public static boolean isBeforeDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        if (cal1.get(Calendar.ERA) < cal2.get(Calendar.ERA)) return true;
        if (cal1.get(Calendar.ERA) > cal2.get(Calendar.ERA)) return false;
        if (cal1.get(Calendar.YEAR) < cal2.get(Calendar.YEAR)) return true;
        if (cal1.get(Calendar.YEAR) > cal2.get(Calendar.YEAR)) return false;
        return cal1.get(Calendar.DAY_OF_YEAR) < cal2.get(Calendar.DAY_OF_YEAR);
    }
    
    /**
     * <p>Checks if the first date is after the second date ignoring time.</p>
     * @param date1 the first date, not altered, not null
     * @param date2 the second date, not altered, not null
     * @return true if the first date day is after the second date day.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isAfterDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isAfterDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if the first calendar date is after the second calendar date ignoring time.</p>
     * @param cal1 the first calendar, not altered, not null.
     * @param cal2 the second calendar, not altered, not null.
     * @return true if cal1 date is after cal2 date ignoring time.
     * @throws IllegalArgumentException if either of the calendars are <code>null</code>
     */
    public static boolean isAfterDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        if (cal1.get(Calendar.ERA) < cal2.get(Calendar.ERA)) return false;
        if (cal1.get(Calendar.ERA) > cal2.get(Calendar.ERA)) return true;
        if (cal1.get(Calendar.YEAR) < cal2.get(Calendar.YEAR)) return false;
        if (cal1.get(Calendar.YEAR) > cal2.get(Calendar.YEAR)) return true;
        return cal1.get(Calendar.DAY_OF_YEAR) > cal2.get(Calendar.DAY_OF_YEAR);
    }
    
    /**
     * <p>Checks if a date is after today and within a number of days in the future.</p>
     * @param date the date to check, not altered, not null.
     * @param days the number of days.
     * @return true if the date day is after today and within days in the future .
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isWithinDaysFuture(Date date, int days) {
        if (date == null) {
            throw new IllegalArgumentException("The date must not be null");
        }
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        return isWithinDaysFuture(cal, days);
    }
    
    /**
     * <p>Checks if a calendar date is after today and within a number of days in the future.</p>
     * @param cal the calendar, not altered, not null
     * @param days the number of days.
     * @return true if the calendar date day is after today and within days in the future .
     * @throws IllegalArgumentException if the calendar is <code>null</code>
     */
    public static boolean isWithinDaysFuture(Calendar cal, int days) {
        if (cal == null) {
            throw new IllegalArgumentException("The date must not be null");
        }
        Calendar today = Calendar.getInstance();
        Calendar future = Calendar.getInstance();
        future.add(Calendar.DAY_OF_YEAR, days);
        return (isAfterDay(cal, today) && ! isAfterDay(cal, future));
    }
    
    /** Returns the given date with the time set to the start of the day. */
    public static Date getStart(Date date) {
        return clearTime(date);
    }
    
    /** Returns the given date with the time values cleared. */
    public static Date clearTime(Date date) {
        if (date == null) {
            return null;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.set(Calendar.HOUR_OF_DAY, 0);
        c.set(Calendar.MINUTE, 0);
        c.set(Calendar.SECOND, 0);
        c.set(Calendar.MILLISECOND, 0);
        return c.getTime();
    }    
    /** Determines whether or not a date has any time values (hour, minute, 
     * seconds or millisecondsReturns the given date with the time values cleared. */
    /**
     * Determines whether or not a date has any time values.
     * @param date The date.
     * @return true iff the date is not null and any of the date"s hour, minute,
     * seconds or millisecond values are greater than zero.
     */
    public static boolean hasTime(Date date) {
        if (date == null) {
            return false;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        if (c.get(Calendar.HOUR_OF_DAY) > 0) {
            return true;
        }
        if (c.get(Calendar.MINUTE) > 0) {
            return true;
        }
        if (c.get(Calendar.SECOND) > 0) {
            return true;
        }
        if (c.get(Calendar.MILLISECOND) > 0) {
            return true;
        }
        return false;
    }
    /** Returns the given date with time set to the end of the day */
    public static Date getEnd(Date date) {
        if (date == null) {
            return null;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.set(Calendar.HOUR_OF_DAY, 23);
        c.set(Calendar.MINUTE, 59);
        c.set(Calendar.SECOND, 59);
        c.set(Calendar.MILLISECOND, 999);
        return c.getTime();
    }
    /** 
     * Returns the maximum of two dates. A null date is treated as being less
     * than any non-null date. 
     */
    public static Date max(Date d1, Date d2) {
        if (d1 == null && d2 == null) return null;
        if (d1 == null) return d2;
        if (d2 == null) return d1;
        return (d1.after(d2)) ? d1 : d2;
    }
    
    /** 
     * Returns the minimum of two dates. A null date is treated as being greater
     * than any non-null date. 
     */
    public static Date min(Date d1, Date d2) {
        if (d1 == null && d2 == null) return null;
        if (d1 == null) return d2;
        if (d2 == null) return d1;
        return (d1.before(d2)) ? d1 : d2;
    }
    /** The maximum date possible. */
    public static Date MAX_DATE = new Date(Long.MAX_VALUE);
    
}





Checks if a date is after today and within a number of days in the future

   

import java.util.Calendar;
import java.util.Date;
public class DateUtils {
    
    /**
     * <p>Checks if two dates are on the same day ignoring time.</p>
     * @param date1  the first date, not altered, not null
     * @param date2  the second date, not altered, not null
     * @return true if they represent the same day
     * @throws IllegalArgumentException if either date is <code>null</code>
     */
    public static boolean isSameDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isSameDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if two calendars represent the same day ignoring time.</p>
     * @param cal1  the first calendar, not altered, not null
     * @param cal2  the second calendar, not altered, not null
     * @return true if they represent the same day
     * @throws IllegalArgumentException if either calendar is <code>null</code>
     */
    public static boolean isSameDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        return (cal1.get(Calendar.ERA) == cal2.get(Calendar.ERA) &&
                cal1.get(Calendar.YEAR) == cal2.get(Calendar.YEAR) &&
                cal1.get(Calendar.DAY_OF_YEAR) == cal2.get(Calendar.DAY_OF_YEAR));
    }
    
    /**
     * <p>Checks if a date is today.</p>
     * @param date the date, not altered, not null.
     * @return true if the date is today.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isToday(Date date) {
        return isSameDay(date, Calendar.getInstance().getTime());
    }
    
    /**
     * <p>Checks if a calendar date is today.</p>
     * @param cal  the calendar, not altered, not null
     * @return true if cal date is today
     * @throws IllegalArgumentException if the calendar is <code>null</code>
     */
    public static boolean isToday(Calendar cal) {
        return isSameDay(cal, Calendar.getInstance());
    }
    
    /**
     * <p>Checks if the first date is before the second date ignoring time.</p>
     * @param date1 the first date, not altered, not null
     * @param date2 the second date, not altered, not null
     * @return true if the first date day is before the second date day.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isBeforeDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isBeforeDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if the first calendar date is before the second calendar date ignoring time.</p>
     * @param cal1 the first calendar, not altered, not null.
     * @param cal2 the second calendar, not altered, not null.
     * @return true if cal1 date is before cal2 date ignoring time.
     * @throws IllegalArgumentException if either of the calendars are <code>null</code>
     */
    public static boolean isBeforeDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        if (cal1.get(Calendar.ERA) < cal2.get(Calendar.ERA)) return true;
        if (cal1.get(Calendar.ERA) > cal2.get(Calendar.ERA)) return false;
        if (cal1.get(Calendar.YEAR) < cal2.get(Calendar.YEAR)) return true;
        if (cal1.get(Calendar.YEAR) > cal2.get(Calendar.YEAR)) return false;
        return cal1.get(Calendar.DAY_OF_YEAR) < cal2.get(Calendar.DAY_OF_YEAR);
    }
    
    /**
     * <p>Checks if the first date is after the second date ignoring time.</p>
     * @param date1 the first date, not altered, not null
     * @param date2 the second date, not altered, not null
     * @return true if the first date day is after the second date day.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isAfterDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isAfterDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if the first calendar date is after the second calendar date ignoring time.</p>
     * @param cal1 the first calendar, not altered, not null.
     * @param cal2 the second calendar, not altered, not null.
     * @return true if cal1 date is after cal2 date ignoring time.
     * @throws IllegalArgumentException if either of the calendars are <code>null</code>
     */
    public static boolean isAfterDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        if (cal1.get(Calendar.ERA) < cal2.get(Calendar.ERA)) return false;
        if (cal1.get(Calendar.ERA) > cal2.get(Calendar.ERA)) return true;
        if (cal1.get(Calendar.YEAR) < cal2.get(Calendar.YEAR)) return false;
        if (cal1.get(Calendar.YEAR) > cal2.get(Calendar.YEAR)) return true;
        return cal1.get(Calendar.DAY_OF_YEAR) > cal2.get(Calendar.DAY_OF_YEAR);
    }
    
    /**
     * <p>Checks if a date is after today and within a number of days in the future.</p>
     * @param date the date to check, not altered, not null.
     * @param days the number of days.
     * @return true if the date day is after today and within days in the future .
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isWithinDaysFuture(Date date, int days) {
        if (date == null) {
            throw new IllegalArgumentException("The date must not be null");
        }
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        return isWithinDaysFuture(cal, days);
    }
    
    /**
     * <p>Checks if a calendar date is after today and within a number of days in the future.</p>
     * @param cal the calendar, not altered, not null
     * @param days the number of days.
     * @return true if the calendar date day is after today and within days in the future .
     * @throws IllegalArgumentException if the calendar is <code>null</code>
     */
    public static boolean isWithinDaysFuture(Calendar cal, int days) {
        if (cal == null) {
            throw new IllegalArgumentException("The date must not be null");
        }
        Calendar today = Calendar.getInstance();
        Calendar future = Calendar.getInstance();
        future.add(Calendar.DAY_OF_YEAR, days);
        return (isAfterDay(cal, today) && ! isAfterDay(cal, future));
    }
    
    /** Returns the given date with the time set to the start of the day. */
    public static Date getStart(Date date) {
        return clearTime(date);
    }
    
    /** Returns the given date with the time values cleared. */
    public static Date clearTime(Date date) {
        if (date == null) {
            return null;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.set(Calendar.HOUR_OF_DAY, 0);
        c.set(Calendar.MINUTE, 0);
        c.set(Calendar.SECOND, 0);
        c.set(Calendar.MILLISECOND, 0);
        return c.getTime();
    }    
    /** Determines whether or not a date has any time values (hour, minute, 
     * seconds or millisecondsReturns the given date with the time values cleared. */
    /**
     * Determines whether or not a date has any time values.
     * @param date The date.
     * @return true iff the date is not null and any of the date"s hour, minute,
     * seconds or millisecond values are greater than zero.
     */
    public static boolean hasTime(Date date) {
        if (date == null) {
            return false;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        if (c.get(Calendar.HOUR_OF_DAY) > 0) {
            return true;
        }
        if (c.get(Calendar.MINUTE) > 0) {
            return true;
        }
        if (c.get(Calendar.SECOND) > 0) {
            return true;
        }
        if (c.get(Calendar.MILLISECOND) > 0) {
            return true;
        }
        return false;
    }
    /** Returns the given date with time set to the end of the day */
    public static Date getEnd(Date date) {
        if (date == null) {
            return null;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.set(Calendar.HOUR_OF_DAY, 23);
        c.set(Calendar.MINUTE, 59);
        c.set(Calendar.SECOND, 59);
        c.set(Calendar.MILLISECOND, 999);
        return c.getTime();
    }
    /** 
     * Returns the maximum of two dates. A null date is treated as being less
     * than any non-null date. 
     */
    public static Date max(Date d1, Date d2) {
        if (d1 == null && d2 == null) return null;
        if (d1 == null) return d2;
        if (d2 == null) return d1;
        return (d1.after(d2)) ? d1 : d2;
    }
    
    /** 
     * Returns the minimum of two dates. A null date is treated as being greater
     * than any non-null date. 
     */
    public static Date min(Date d1, Date d2) {
        if (d1 == null && d2 == null) return null;
        if (d1 == null) return d2;
        if (d2 == null) return d1;
        return (d1.before(d2)) ? d1 : d2;
    }
    /** The maximum date possible. */
    public static Date MAX_DATE = new Date(Long.MAX_VALUE);
    
}





Checks if the first calendar date is after the second calendar date ignoring time

   

import java.util.Calendar;
import java.util.Date;
public class DateUtils {
    
    /**
     * <p>Checks if two dates are on the same day ignoring time.</p>
     * @param date1  the first date, not altered, not null
     * @param date2  the second date, not altered, not null
     * @return true if they represent the same day
     * @throws IllegalArgumentException if either date is <code>null</code>
     */
    public static boolean isSameDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isSameDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if two calendars represent the same day ignoring time.</p>
     * @param cal1  the first calendar, not altered, not null
     * @param cal2  the second calendar, not altered, not null
     * @return true if they represent the same day
     * @throws IllegalArgumentException if either calendar is <code>null</code>
     */
    public static boolean isSameDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        return (cal1.get(Calendar.ERA) == cal2.get(Calendar.ERA) &&
                cal1.get(Calendar.YEAR) == cal2.get(Calendar.YEAR) &&
                cal1.get(Calendar.DAY_OF_YEAR) == cal2.get(Calendar.DAY_OF_YEAR));
    }
    
    /**
     * <p>Checks if a date is today.</p>
     * @param date the date, not altered, not null.
     * @return true if the date is today.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isToday(Date date) {
        return isSameDay(date, Calendar.getInstance().getTime());
    }
    
    /**
     * <p>Checks if a calendar date is today.</p>
     * @param cal  the calendar, not altered, not null
     * @return true if cal date is today
     * @throws IllegalArgumentException if the calendar is <code>null</code>
     */
    public static boolean isToday(Calendar cal) {
        return isSameDay(cal, Calendar.getInstance());
    }
    
    /**
     * <p>Checks if the first date is before the second date ignoring time.</p>
     * @param date1 the first date, not altered, not null
     * @param date2 the second date, not altered, not null
     * @return true if the first date day is before the second date day.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isBeforeDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isBeforeDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if the first calendar date is before the second calendar date ignoring time.</p>
     * @param cal1 the first calendar, not altered, not null.
     * @param cal2 the second calendar, not altered, not null.
     * @return true if cal1 date is before cal2 date ignoring time.
     * @throws IllegalArgumentException if either of the calendars are <code>null</code>
     */
    public static boolean isBeforeDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        if (cal1.get(Calendar.ERA) < cal2.get(Calendar.ERA)) return true;
        if (cal1.get(Calendar.ERA) > cal2.get(Calendar.ERA)) return false;
        if (cal1.get(Calendar.YEAR) < cal2.get(Calendar.YEAR)) return true;
        if (cal1.get(Calendar.YEAR) > cal2.get(Calendar.YEAR)) return false;
        return cal1.get(Calendar.DAY_OF_YEAR) < cal2.get(Calendar.DAY_OF_YEAR);
    }
    
    /**
     * <p>Checks if the first date is after the second date ignoring time.</p>
     * @param date1 the first date, not altered, not null
     * @param date2 the second date, not altered, not null
     * @return true if the first date day is after the second date day.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isAfterDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isAfterDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if the first calendar date is after the second calendar date ignoring time.</p>
     * @param cal1 the first calendar, not altered, not null.
     * @param cal2 the second calendar, not altered, not null.
     * @return true if cal1 date is after cal2 date ignoring time.
     * @throws IllegalArgumentException if either of the calendars are <code>null</code>
     */
    public static boolean isAfterDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        if (cal1.get(Calendar.ERA) < cal2.get(Calendar.ERA)) return false;
        if (cal1.get(Calendar.ERA) > cal2.get(Calendar.ERA)) return true;
        if (cal1.get(Calendar.YEAR) < cal2.get(Calendar.YEAR)) return false;
        if (cal1.get(Calendar.YEAR) > cal2.get(Calendar.YEAR)) return true;
        return cal1.get(Calendar.DAY_OF_YEAR) > cal2.get(Calendar.DAY_OF_YEAR);
    }
    
    /**
     * <p>Checks if a date is after today and within a number of days in the future.</p>
     * @param date the date to check, not altered, not null.
     * @param days the number of days.
     * @return true if the date day is after today and within days in the future .
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isWithinDaysFuture(Date date, int days) {
        if (date == null) {
            throw new IllegalArgumentException("The date must not be null");
        }
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        return isWithinDaysFuture(cal, days);
    }
    
    /**
     * <p>Checks if a calendar date is after today and within a number of days in the future.</p>
     * @param cal the calendar, not altered, not null
     * @param days the number of days.
     * @return true if the calendar date day is after today and within days in the future .
     * @throws IllegalArgumentException if the calendar is <code>null</code>
     */
    public static boolean isWithinDaysFuture(Calendar cal, int days) {
        if (cal == null) {
            throw new IllegalArgumentException("The date must not be null");
        }
        Calendar today = Calendar.getInstance();
        Calendar future = Calendar.getInstance();
        future.add(Calendar.DAY_OF_YEAR, days);
        return (isAfterDay(cal, today) && ! isAfterDay(cal, future));
    }
    
    /** Returns the given date with the time set to the start of the day. */
    public static Date getStart(Date date) {
        return clearTime(date);
    }
    
    /** Returns the given date with the time values cleared. */
    public static Date clearTime(Date date) {
        if (date == null) {
            return null;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.set(Calendar.HOUR_OF_DAY, 0);
        c.set(Calendar.MINUTE, 0);
        c.set(Calendar.SECOND, 0);
        c.set(Calendar.MILLISECOND, 0);
        return c.getTime();
    }    
    /** Determines whether or not a date has any time values (hour, minute, 
     * seconds or millisecondsReturns the given date with the time values cleared. */
    /**
     * Determines whether or not a date has any time values.
     * @param date The date.
     * @return true iff the date is not null and any of the date"s hour, minute,
     * seconds or millisecond values are greater than zero.
     */
    public static boolean hasTime(Date date) {
        if (date == null) {
            return false;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        if (c.get(Calendar.HOUR_OF_DAY) > 0) {
            return true;
        }
        if (c.get(Calendar.MINUTE) > 0) {
            return true;
        }
        if (c.get(Calendar.SECOND) > 0) {
            return true;
        }
        if (c.get(Calendar.MILLISECOND) > 0) {
            return true;
        }
        return false;
    }
    /** Returns the given date with time set to the end of the day */
    public static Date getEnd(Date date) {
        if (date == null) {
            return null;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.set(Calendar.HOUR_OF_DAY, 23);
        c.set(Calendar.MINUTE, 59);
        c.set(Calendar.SECOND, 59);
        c.set(Calendar.MILLISECOND, 999);
        return c.getTime();
    }
    /** 
     * Returns the maximum of two dates. A null date is treated as being less
     * than any non-null date. 
     */
    public static Date max(Date d1, Date d2) {
        if (d1 == null && d2 == null) return null;
        if (d1 == null) return d2;
        if (d2 == null) return d1;
        return (d1.after(d2)) ? d1 : d2;
    }
    
    /** 
     * Returns the minimum of two dates. A null date is treated as being greater
     * than any non-null date. 
     */
    public static Date min(Date d1, Date d2) {
        if (d1 == null && d2 == null) return null;
        if (d1 == null) return d2;
        if (d2 == null) return d1;
        return (d1.before(d2)) ? d1 : d2;
    }
    /** The maximum date possible. */
    public static Date MAX_DATE = new Date(Long.MAX_VALUE);
    
}





Checks if the first calendar date is before the second calendar date ignoring time

   

import java.util.Calendar;
import java.util.Date;
public class DateUtils {
    
    /**
     * <p>Checks if two dates are on the same day ignoring time.</p>
     * @param date1  the first date, not altered, not null
     * @param date2  the second date, not altered, not null
     * @return true if they represent the same day
     * @throws IllegalArgumentException if either date is <code>null</code>
     */
    public static boolean isSameDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isSameDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if two calendars represent the same day ignoring time.</p>
     * @param cal1  the first calendar, not altered, not null
     * @param cal2  the second calendar, not altered, not null
     * @return true if they represent the same day
     * @throws IllegalArgumentException if either calendar is <code>null</code>
     */
    public static boolean isSameDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        return (cal1.get(Calendar.ERA) == cal2.get(Calendar.ERA) &&
                cal1.get(Calendar.YEAR) == cal2.get(Calendar.YEAR) &&
                cal1.get(Calendar.DAY_OF_YEAR) == cal2.get(Calendar.DAY_OF_YEAR));
    }
    
    /**
     * <p>Checks if a date is today.</p>
     * @param date the date, not altered, not null.
     * @return true if the date is today.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isToday(Date date) {
        return isSameDay(date, Calendar.getInstance().getTime());
    }
    
    /**
     * <p>Checks if a calendar date is today.</p>
     * @param cal  the calendar, not altered, not null
     * @return true if cal date is today
     * @throws IllegalArgumentException if the calendar is <code>null</code>
     */
    public static boolean isToday(Calendar cal) {
        return isSameDay(cal, Calendar.getInstance());
    }
    
    /**
     * <p>Checks if the first date is before the second date ignoring time.</p>
     * @param date1 the first date, not altered, not null
     * @param date2 the second date, not altered, not null
     * @return true if the first date day is before the second date day.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isBeforeDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isBeforeDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if the first calendar date is before the second calendar date ignoring time.</p>
     * @param cal1 the first calendar, not altered, not null.
     * @param cal2 the second calendar, not altered, not null.
     * @return true if cal1 date is before cal2 date ignoring time.
     * @throws IllegalArgumentException if either of the calendars are <code>null</code>
     */
    public static boolean isBeforeDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        if (cal1.get(Calendar.ERA) < cal2.get(Calendar.ERA)) return true;
        if (cal1.get(Calendar.ERA) > cal2.get(Calendar.ERA)) return false;
        if (cal1.get(Calendar.YEAR) < cal2.get(Calendar.YEAR)) return true;
        if (cal1.get(Calendar.YEAR) > cal2.get(Calendar.YEAR)) return false;
        return cal1.get(Calendar.DAY_OF_YEAR) < cal2.get(Calendar.DAY_OF_YEAR);
    }
    
    /**
     * <p>Checks if the first date is after the second date ignoring time.</p>
     * @param date1 the first date, not altered, not null
     * @param date2 the second date, not altered, not null
     * @return true if the first date day is after the second date day.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isAfterDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isAfterDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if the first calendar date is after the second calendar date ignoring time.</p>
     * @param cal1 the first calendar, not altered, not null.
     * @param cal2 the second calendar, not altered, not null.
     * @return true if cal1 date is after cal2 date ignoring time.
     * @throws IllegalArgumentException if either of the calendars are <code>null</code>
     */
    public static boolean isAfterDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        if (cal1.get(Calendar.ERA) < cal2.get(Calendar.ERA)) return false;
        if (cal1.get(Calendar.ERA) > cal2.get(Calendar.ERA)) return true;
        if (cal1.get(Calendar.YEAR) < cal2.get(Calendar.YEAR)) return false;
        if (cal1.get(Calendar.YEAR) > cal2.get(Calendar.YEAR)) return true;
        return cal1.get(Calendar.DAY_OF_YEAR) > cal2.get(Calendar.DAY_OF_YEAR);
    }
    
    /**
     * <p>Checks if a date is after today and within a number of days in the future.</p>
     * @param date the date to check, not altered, not null.
     * @param days the number of days.
     * @return true if the date day is after today and within days in the future .
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isWithinDaysFuture(Date date, int days) {
        if (date == null) {
            throw new IllegalArgumentException("The date must not be null");
        }
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        return isWithinDaysFuture(cal, days);
    }
    
    /**
     * <p>Checks if a calendar date is after today and within a number of days in the future.</p>
     * @param cal the calendar, not altered, not null
     * @param days the number of days.
     * @return true if the calendar date day is after today and within days in the future .
     * @throws IllegalArgumentException if the calendar is <code>null</code>
     */
    public static boolean isWithinDaysFuture(Calendar cal, int days) {
        if (cal == null) {
            throw new IllegalArgumentException("The date must not be null");
        }
        Calendar today = Calendar.getInstance();
        Calendar future = Calendar.getInstance();
        future.add(Calendar.DAY_OF_YEAR, days);
        return (isAfterDay(cal, today) && ! isAfterDay(cal, future));
    }
    
    /** Returns the given date with the time set to the start of the day. */
    public static Date getStart(Date date) {
        return clearTime(date);
    }
    
    /** Returns the given date with the time values cleared. */
    public static Date clearTime(Date date) {
        if (date == null) {
            return null;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.set(Calendar.HOUR_OF_DAY, 0);
        c.set(Calendar.MINUTE, 0);
        c.set(Calendar.SECOND, 0);
        c.set(Calendar.MILLISECOND, 0);
        return c.getTime();
    }    
    /** Determines whether or not a date has any time values (hour, minute, 
     * seconds or millisecondsReturns the given date with the time values cleared. */
    /**
     * Determines whether or not a date has any time values.
     * @param date The date.
     * @return true iff the date is not null and any of the date"s hour, minute,
     * seconds or millisecond values are greater than zero.
     */
    public static boolean hasTime(Date date) {
        if (date == null) {
            return false;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        if (c.get(Calendar.HOUR_OF_DAY) > 0) {
            return true;
        }
        if (c.get(Calendar.MINUTE) > 0) {
            return true;
        }
        if (c.get(Calendar.SECOND) > 0) {
            return true;
        }
        if (c.get(Calendar.MILLISECOND) > 0) {
            return true;
        }
        return false;
    }
    /** Returns the given date with time set to the end of the day */
    public static Date getEnd(Date date) {
        if (date == null) {
            return null;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.set(Calendar.HOUR_OF_DAY, 23);
        c.set(Calendar.MINUTE, 59);
        c.set(Calendar.SECOND, 59);
        c.set(Calendar.MILLISECOND, 999);
        return c.getTime();
    }
    /** 
     * Returns the maximum of two dates. A null date is treated as being less
     * than any non-null date. 
     */
    public static Date max(Date d1, Date d2) {
        if (d1 == null && d2 == null) return null;
        if (d1 == null) return d2;
        if (d2 == null) return d1;
        return (d1.after(d2)) ? d1 : d2;
    }
    
    /** 
     * Returns the minimum of two dates. A null date is treated as being greater
     * than any non-null date. 
     */
    public static Date min(Date d1, Date d2) {
        if (d1 == null && d2 == null) return null;
        if (d1 == null) return d2;
        if (d2 == null) return d1;
        return (d1.before(d2)) ? d1 : d2;
    }
    /** The maximum date possible. */
    public static Date MAX_DATE = new Date(Long.MAX_VALUE);
    
}





Checks if the first date is after the second date ignoring time

   

import java.util.Calendar;
import java.util.Date;
public class DateUtils {
    
    /**
     * <p>Checks if two dates are on the same day ignoring time.</p>
     * @param date1  the first date, not altered, not null
     * @param date2  the second date, not altered, not null
     * @return true if they represent the same day
     * @throws IllegalArgumentException if either date is <code>null</code>
     */
    public static boolean isSameDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isSameDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if two calendars represent the same day ignoring time.</p>
     * @param cal1  the first calendar, not altered, not null
     * @param cal2  the second calendar, not altered, not null
     * @return true if they represent the same day
     * @throws IllegalArgumentException if either calendar is <code>null</code>
     */
    public static boolean isSameDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        return (cal1.get(Calendar.ERA) == cal2.get(Calendar.ERA) &&
                cal1.get(Calendar.YEAR) == cal2.get(Calendar.YEAR) &&
                cal1.get(Calendar.DAY_OF_YEAR) == cal2.get(Calendar.DAY_OF_YEAR));
    }
    
    /**
     * <p>Checks if a date is today.</p>
     * @param date the date, not altered, not null.
     * @return true if the date is today.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isToday(Date date) {
        return isSameDay(date, Calendar.getInstance().getTime());
    }
    
    /**
     * <p>Checks if a calendar date is today.</p>
     * @param cal  the calendar, not altered, not null
     * @return true if cal date is today
     * @throws IllegalArgumentException if the calendar is <code>null</code>
     */
    public static boolean isToday(Calendar cal) {
        return isSameDay(cal, Calendar.getInstance());
    }
    
    /**
     * <p>Checks if the first date is before the second date ignoring time.</p>
     * @param date1 the first date, not altered, not null
     * @param date2 the second date, not altered, not null
     * @return true if the first date day is before the second date day.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isBeforeDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isBeforeDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if the first calendar date is before the second calendar date ignoring time.</p>
     * @param cal1 the first calendar, not altered, not null.
     * @param cal2 the second calendar, not altered, not null.
     * @return true if cal1 date is before cal2 date ignoring time.
     * @throws IllegalArgumentException if either of the calendars are <code>null</code>
     */
    public static boolean isBeforeDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        if (cal1.get(Calendar.ERA) < cal2.get(Calendar.ERA)) return true;
        if (cal1.get(Calendar.ERA) > cal2.get(Calendar.ERA)) return false;
        if (cal1.get(Calendar.YEAR) < cal2.get(Calendar.YEAR)) return true;
        if (cal1.get(Calendar.YEAR) > cal2.get(Calendar.YEAR)) return false;
        return cal1.get(Calendar.DAY_OF_YEAR) < cal2.get(Calendar.DAY_OF_YEAR);
    }
    
    /**
     * <p>Checks if the first date is after the second date ignoring time.</p>
     * @param date1 the first date, not altered, not null
     * @param date2 the second date, not altered, not null
     * @return true if the first date day is after the second date day.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isAfterDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isAfterDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if the first calendar date is after the second calendar date ignoring time.</p>
     * @param cal1 the first calendar, not altered, not null.
     * @param cal2 the second calendar, not altered, not null.
     * @return true if cal1 date is after cal2 date ignoring time.
     * @throws IllegalArgumentException if either of the calendars are <code>null</code>
     */
    public static boolean isAfterDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        if (cal1.get(Calendar.ERA) < cal2.get(Calendar.ERA)) return false;
        if (cal1.get(Calendar.ERA) > cal2.get(Calendar.ERA)) return true;
        if (cal1.get(Calendar.YEAR) < cal2.get(Calendar.YEAR)) return false;
        if (cal1.get(Calendar.YEAR) > cal2.get(Calendar.YEAR)) return true;
        return cal1.get(Calendar.DAY_OF_YEAR) > cal2.get(Calendar.DAY_OF_YEAR);
    }
    
    /**
     * <p>Checks if a date is after today and within a number of days in the future.</p>
     * @param date the date to check, not altered, not null.
     * @param days the number of days.
     * @return true if the date day is after today and within days in the future .
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isWithinDaysFuture(Date date, int days) {
        if (date == null) {
            throw new IllegalArgumentException("The date must not be null");
        }
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        return isWithinDaysFuture(cal, days);
    }
    
    /**
     * <p>Checks if a calendar date is after today and within a number of days in the future.</p>
     * @param cal the calendar, not altered, not null
     * @param days the number of days.
     * @return true if the calendar date day is after today and within days in the future .
     * @throws IllegalArgumentException if the calendar is <code>null</code>
     */
    public static boolean isWithinDaysFuture(Calendar cal, int days) {
        if (cal == null) {
            throw new IllegalArgumentException("The date must not be null");
        }
        Calendar today = Calendar.getInstance();
        Calendar future = Calendar.getInstance();
        future.add(Calendar.DAY_OF_YEAR, days);
        return (isAfterDay(cal, today) && ! isAfterDay(cal, future));
    }
    
    /** Returns the given date with the time set to the start of the day. */
    public static Date getStart(Date date) {
        return clearTime(date);
    }
    
    /** Returns the given date with the time values cleared. */
    public static Date clearTime(Date date) {
        if (date == null) {
            return null;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.set(Calendar.HOUR_OF_DAY, 0);
        c.set(Calendar.MINUTE, 0);
        c.set(Calendar.SECOND, 0);
        c.set(Calendar.MILLISECOND, 0);
        return c.getTime();
    }    
    /** Determines whether or not a date has any time values (hour, minute, 
     * seconds or millisecondsReturns the given date with the time values cleared. */
    /**
     * Determines whether or not a date has any time values.
     * @param date The date.
     * @return true iff the date is not null and any of the date"s hour, minute,
     * seconds or millisecond values are greater than zero.
     */
    public static boolean hasTime(Date date) {
        if (date == null) {
            return false;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        if (c.get(Calendar.HOUR_OF_DAY) > 0) {
            return true;
        }
        if (c.get(Calendar.MINUTE) > 0) {
            return true;
        }
        if (c.get(Calendar.SECOND) > 0) {
            return true;
        }
        if (c.get(Calendar.MILLISECOND) > 0) {
            return true;
        }
        return false;
    }
    /** Returns the given date with time set to the end of the day */
    public static Date getEnd(Date date) {
        if (date == null) {
            return null;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.set(Calendar.HOUR_OF_DAY, 23);
        c.set(Calendar.MINUTE, 59);
        c.set(Calendar.SECOND, 59);
        c.set(Calendar.MILLISECOND, 999);
        return c.getTime();
    }
    /** 
     * Returns the maximum of two dates. A null date is treated as being less
     * than any non-null date. 
     */
    public static Date max(Date d1, Date d2) {
        if (d1 == null && d2 == null) return null;
        if (d1 == null) return d2;
        if (d2 == null) return d1;
        return (d1.after(d2)) ? d1 : d2;
    }
    
    /** 
     * Returns the minimum of two dates. A null date is treated as being greater
     * than any non-null date. 
     */
    public static Date min(Date d1, Date d2) {
        if (d1 == null && d2 == null) return null;
        if (d1 == null) return d2;
        if (d2 == null) return d1;
        return (d1.before(d2)) ? d1 : d2;
    }
    /** The maximum date possible. */
    public static Date MAX_DATE = new Date(Long.MAX_VALUE);
    
}





Checks if the first date is before the second date ignoring time

   

import java.util.Calendar;
import java.util.Date;
public class DateUtils {
    
    /**
     * <p>Checks if two dates are on the same day ignoring time.</p>
     * @param date1  the first date, not altered, not null
     * @param date2  the second date, not altered, not null
     * @return true if they represent the same day
     * @throws IllegalArgumentException if either date is <code>null</code>
     */
    public static boolean isSameDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isSameDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if two calendars represent the same day ignoring time.</p>
     * @param cal1  the first calendar, not altered, not null
     * @param cal2  the second calendar, not altered, not null
     * @return true if they represent the same day
     * @throws IllegalArgumentException if either calendar is <code>null</code>
     */
    public static boolean isSameDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        return (cal1.get(Calendar.ERA) == cal2.get(Calendar.ERA) &&
                cal1.get(Calendar.YEAR) == cal2.get(Calendar.YEAR) &&
                cal1.get(Calendar.DAY_OF_YEAR) == cal2.get(Calendar.DAY_OF_YEAR));
    }
    
    /**
     * <p>Checks if a date is today.</p>
     * @param date the date, not altered, not null.
     * @return true if the date is today.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isToday(Date date) {
        return isSameDay(date, Calendar.getInstance().getTime());
    }
    
    /**
     * <p>Checks if a calendar date is today.</p>
     * @param cal  the calendar, not altered, not null
     * @return true if cal date is today
     * @throws IllegalArgumentException if the calendar is <code>null</code>
     */
    public static boolean isToday(Calendar cal) {
        return isSameDay(cal, Calendar.getInstance());
    }
    
    /**
     * <p>Checks if the first date is before the second date ignoring time.</p>
     * @param date1 the first date, not altered, not null
     * @param date2 the second date, not altered, not null
     * @return true if the first date day is before the second date day.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isBeforeDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isBeforeDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if the first calendar date is before the second calendar date ignoring time.</p>
     * @param cal1 the first calendar, not altered, not null.
     * @param cal2 the second calendar, not altered, not null.
     * @return true if cal1 date is before cal2 date ignoring time.
     * @throws IllegalArgumentException if either of the calendars are <code>null</code>
     */
    public static boolean isBeforeDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        if (cal1.get(Calendar.ERA) < cal2.get(Calendar.ERA)) return true;
        if (cal1.get(Calendar.ERA) > cal2.get(Calendar.ERA)) return false;
        if (cal1.get(Calendar.YEAR) < cal2.get(Calendar.YEAR)) return true;
        if (cal1.get(Calendar.YEAR) > cal2.get(Calendar.YEAR)) return false;
        return cal1.get(Calendar.DAY_OF_YEAR) < cal2.get(Calendar.DAY_OF_YEAR);
    }
    
    /**
     * <p>Checks if the first date is after the second date ignoring time.</p>
     * @param date1 the first date, not altered, not null
     * @param date2 the second date, not altered, not null
     * @return true if the first date day is after the second date day.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isAfterDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isAfterDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if the first calendar date is after the second calendar date ignoring time.</p>
     * @param cal1 the first calendar, not altered, not null.
     * @param cal2 the second calendar, not altered, not null.
     * @return true if cal1 date is after cal2 date ignoring time.
     * @throws IllegalArgumentException if either of the calendars are <code>null</code>
     */
    public static boolean isAfterDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        if (cal1.get(Calendar.ERA) < cal2.get(Calendar.ERA)) return false;
        if (cal1.get(Calendar.ERA) > cal2.get(Calendar.ERA)) return true;
        if (cal1.get(Calendar.YEAR) < cal2.get(Calendar.YEAR)) return false;
        if (cal1.get(Calendar.YEAR) > cal2.get(Calendar.YEAR)) return true;
        return cal1.get(Calendar.DAY_OF_YEAR) > cal2.get(Calendar.DAY_OF_YEAR);
    }
    
    /**
     * <p>Checks if a date is after today and within a number of days in the future.</p>
     * @param date the date to check, not altered, not null.
     * @param days the number of days.
     * @return true if the date day is after today and within days in the future .
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isWithinDaysFuture(Date date, int days) {
        if (date == null) {
            throw new IllegalArgumentException("The date must not be null");
        }
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        return isWithinDaysFuture(cal, days);
    }
    
    /**
     * <p>Checks if a calendar date is after today and within a number of days in the future.</p>
     * @param cal the calendar, not altered, not null
     * @param days the number of days.
     * @return true if the calendar date day is after today and within days in the future .
     * @throws IllegalArgumentException if the calendar is <code>null</code>
     */
    public static boolean isWithinDaysFuture(Calendar cal, int days) {
        if (cal == null) {
            throw new IllegalArgumentException("The date must not be null");
        }
        Calendar today = Calendar.getInstance();
        Calendar future = Calendar.getInstance();
        future.add(Calendar.DAY_OF_YEAR, days);
        return (isAfterDay(cal, today) && ! isAfterDay(cal, future));
    }
    
    /** Returns the given date with the time set to the start of the day. */
    public static Date getStart(Date date) {
        return clearTime(date);
    }
    
    /** Returns the given date with the time values cleared. */
    public static Date clearTime(Date date) {
        if (date == null) {
            return null;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.set(Calendar.HOUR_OF_DAY, 0);
        c.set(Calendar.MINUTE, 0);
        c.set(Calendar.SECOND, 0);
        c.set(Calendar.MILLISECOND, 0);
        return c.getTime();
    }    
    /** Determines whether or not a date has any time values (hour, minute, 
     * seconds or millisecondsReturns the given date with the time values cleared. */
    /**
     * Determines whether or not a date has any time values.
     * @param date The date.
     * @return true iff the date is not null and any of the date"s hour, minute,
     * seconds or millisecond values are greater than zero.
     */
    public static boolean hasTime(Date date) {
        if (date == null) {
            return false;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        if (c.get(Calendar.HOUR_OF_DAY) > 0) {
            return true;
        }
        if (c.get(Calendar.MINUTE) > 0) {
            return true;
        }
        if (c.get(Calendar.SECOND) > 0) {
            return true;
        }
        if (c.get(Calendar.MILLISECOND) > 0) {
            return true;
        }
        return false;
    }
    /** Returns the given date with time set to the end of the day */
    public static Date getEnd(Date date) {
        if (date == null) {
            return null;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.set(Calendar.HOUR_OF_DAY, 23);
        c.set(Calendar.MINUTE, 59);
        c.set(Calendar.SECOND, 59);
        c.set(Calendar.MILLISECOND, 999);
        return c.getTime();
    }
    /** 
     * Returns the maximum of two dates. A null date is treated as being less
     * than any non-null date. 
     */
    public static Date max(Date d1, Date d2) {
        if (d1 == null && d2 == null) return null;
        if (d1 == null) return d2;
        if (d2 == null) return d1;
        return (d1.after(d2)) ? d1 : d2;
    }
    
    /** 
     * Returns the minimum of two dates. A null date is treated as being greater
     * than any non-null date. 
     */
    public static Date min(Date d1, Date d2) {
        if (d1 == null && d2 == null) return null;
        if (d1 == null) return d2;
        if (d2 == null) return d1;
        return (d1.before(d2)) ? d1 : d2;
    }
    /** The maximum date possible. */
    public static Date MAX_DATE = new Date(Long.MAX_VALUE);
    
}





Checks if two calendars represent the same day ignoring time

   

import java.util.Calendar;
import java.util.Date;
public class DateUtils {
    
    /**
     * <p>Checks if two dates are on the same day ignoring time.</p>
     * @param date1  the first date, not altered, not null
     * @param date2  the second date, not altered, not null
     * @return true if they represent the same day
     * @throws IllegalArgumentException if either date is <code>null</code>
     */
    public static boolean isSameDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isSameDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if two calendars represent the same day ignoring time.</p>
     * @param cal1  the first calendar, not altered, not null
     * @param cal2  the second calendar, not altered, not null
     * @return true if they represent the same day
     * @throws IllegalArgumentException if either calendar is <code>null</code>
     */
    public static boolean isSameDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        return (cal1.get(Calendar.ERA) == cal2.get(Calendar.ERA) &&
                cal1.get(Calendar.YEAR) == cal2.get(Calendar.YEAR) &&
                cal1.get(Calendar.DAY_OF_YEAR) == cal2.get(Calendar.DAY_OF_YEAR));
    }
    
    /**
     * <p>Checks if a date is today.</p>
     * @param date the date, not altered, not null.
     * @return true if the date is today.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isToday(Date date) {
        return isSameDay(date, Calendar.getInstance().getTime());
    }
    
    /**
     * <p>Checks if a calendar date is today.</p>
     * @param cal  the calendar, not altered, not null
     * @return true if cal date is today
     * @throws IllegalArgumentException if the calendar is <code>null</code>
     */
    public static boolean isToday(Calendar cal) {
        return isSameDay(cal, Calendar.getInstance());
    }
    
    /**
     * <p>Checks if the first date is before the second date ignoring time.</p>
     * @param date1 the first date, not altered, not null
     * @param date2 the second date, not altered, not null
     * @return true if the first date day is before the second date day.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isBeforeDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isBeforeDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if the first calendar date is before the second calendar date ignoring time.</p>
     * @param cal1 the first calendar, not altered, not null.
     * @param cal2 the second calendar, not altered, not null.
     * @return true if cal1 date is before cal2 date ignoring time.
     * @throws IllegalArgumentException if either of the calendars are <code>null</code>
     */
    public static boolean isBeforeDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        if (cal1.get(Calendar.ERA) < cal2.get(Calendar.ERA)) return true;
        if (cal1.get(Calendar.ERA) > cal2.get(Calendar.ERA)) return false;
        if (cal1.get(Calendar.YEAR) < cal2.get(Calendar.YEAR)) return true;
        if (cal1.get(Calendar.YEAR) > cal2.get(Calendar.YEAR)) return false;
        return cal1.get(Calendar.DAY_OF_YEAR) < cal2.get(Calendar.DAY_OF_YEAR);
    }
    
    /**
     * <p>Checks if the first date is after the second date ignoring time.</p>
     * @param date1 the first date, not altered, not null
     * @param date2 the second date, not altered, not null
     * @return true if the first date day is after the second date day.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isAfterDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isAfterDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if the first calendar date is after the second calendar date ignoring time.</p>
     * @param cal1 the first calendar, not altered, not null.
     * @param cal2 the second calendar, not altered, not null.
     * @return true if cal1 date is after cal2 date ignoring time.
     * @throws IllegalArgumentException if either of the calendars are <code>null</code>
     */
    public static boolean isAfterDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        if (cal1.get(Calendar.ERA) < cal2.get(Calendar.ERA)) return false;
        if (cal1.get(Calendar.ERA) > cal2.get(Calendar.ERA)) return true;
        if (cal1.get(Calendar.YEAR) < cal2.get(Calendar.YEAR)) return false;
        if (cal1.get(Calendar.YEAR) > cal2.get(Calendar.YEAR)) return true;
        return cal1.get(Calendar.DAY_OF_YEAR) > cal2.get(Calendar.DAY_OF_YEAR);
    }
    
    /**
     * <p>Checks if a date is after today and within a number of days in the future.</p>
     * @param date the date to check, not altered, not null.
     * @param days the number of days.
     * @return true if the date day is after today and within days in the future .
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isWithinDaysFuture(Date date, int days) {
        if (date == null) {
            throw new IllegalArgumentException("The date must not be null");
        }
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        return isWithinDaysFuture(cal, days);
    }
    
    /**
     * <p>Checks if a calendar date is after today and within a number of days in the future.</p>
     * @param cal the calendar, not altered, not null
     * @param days the number of days.
     * @return true if the calendar date day is after today and within days in the future .
     * @throws IllegalArgumentException if the calendar is <code>null</code>
     */
    public static boolean isWithinDaysFuture(Calendar cal, int days) {
        if (cal == null) {
            throw new IllegalArgumentException("The date must not be null");
        }
        Calendar today = Calendar.getInstance();
        Calendar future = Calendar.getInstance();
        future.add(Calendar.DAY_OF_YEAR, days);
        return (isAfterDay(cal, today) && ! isAfterDay(cal, future));
    }
    
    /** Returns the given date with the time set to the start of the day. */
    public static Date getStart(Date date) {
        return clearTime(date);
    }
    
    /** Returns the given date with the time values cleared. */
    public static Date clearTime(Date date) {
        if (date == null) {
            return null;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.set(Calendar.HOUR_OF_DAY, 0);
        c.set(Calendar.MINUTE, 0);
        c.set(Calendar.SECOND, 0);
        c.set(Calendar.MILLISECOND, 0);
        return c.getTime();
    }    
    /** Determines whether or not a date has any time values (hour, minute, 
     * seconds or millisecondsReturns the given date with the time values cleared. */
    /**
     * Determines whether or not a date has any time values.
     * @param date The date.
     * @return true iff the date is not null and any of the date"s hour, minute,
     * seconds or millisecond values are greater than zero.
     */
    public static boolean hasTime(Date date) {
        if (date == null) {
            return false;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        if (c.get(Calendar.HOUR_OF_DAY) > 0) {
            return true;
        }
        if (c.get(Calendar.MINUTE) > 0) {
            return true;
        }
        if (c.get(Calendar.SECOND) > 0) {
            return true;
        }
        if (c.get(Calendar.MILLISECOND) > 0) {
            return true;
        }
        return false;
    }
    /** Returns the given date with time set to the end of the day */
    public static Date getEnd(Date date) {
        if (date == null) {
            return null;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.set(Calendar.HOUR_OF_DAY, 23);
        c.set(Calendar.MINUTE, 59);
        c.set(Calendar.SECOND, 59);
        c.set(Calendar.MILLISECOND, 999);
        return c.getTime();
    }
    /** 
     * Returns the maximum of two dates. A null date is treated as being less
     * than any non-null date. 
     */
    public static Date max(Date d1, Date d2) {
        if (d1 == null && d2 == null) return null;
        if (d1 == null) return d2;
        if (d2 == null) return d1;
        return (d1.after(d2)) ? d1 : d2;
    }
    
    /** 
     * Returns the minimum of two dates. A null date is treated as being greater
     * than any non-null date. 
     */
    public static Date min(Date d1, Date d2) {
        if (d1 == null && d2 == null) return null;
        if (d1 == null) return d2;
        if (d2 == null) return d1;
        return (d1.before(d2)) ? d1 : d2;
    }
    /** The maximum date possible. */
    public static Date MAX_DATE = new Date(Long.MAX_VALUE);
    
}





Checks if two dates are on the same day ignoring time

   
import java.util.Calendar;
import java.util.Date;
/*
 * The contents of this file are subject to the terms of the Common Development
 * and Distribution License (the License). You may not use this file except in
 * compliance with the License.
 *
 * You can get a copy of the License at http://www.thinkingrock.ru.au/cddl.html
 * or http://www.thinkingrock.ru.au/cddl.txt.
 *
 * When distributing Covered Code, include this CDDL Header Notice in each file
 * and include the License file at http://www.thinkingrock.ru.au/cddl.txt.
 * If applicable, add the following below the CDDL Header, with the fields
 * enclosed by brackets [] replaced by your own identifying information:
 * "Portions Copyright [year] [name of copyright owner]"
 *
 * The Original Software is ThinkingRock. The Initial Developer of the Original
 * Software is Avente Pty Ltd, Australia.
 *
 * Portions Copyright 2006-2007 Avente Pty Ltd. All Rights Reserved.
 */
public class Util {
  /**
   * <p>Checks if two dates are on the same day ignoring time.</p>
   * @param date1  the first date, not altered, not null
   * @param date2  the second date, not altered, not null
   * @return true if they represent the same day
   * @throws IllegalArgumentException if either date is <code>null</code>
   */
  public static boolean isSameDay(Date date1, Date date2) {
      if (date1 == null || date2 == null) {
          throw new IllegalArgumentException("The dates must not be null");
      }
      Calendar cal1 = Calendar.getInstance();
      cal1.setTime(date1);
      Calendar cal2 = Calendar.getInstance();
      cal2.setTime(date2);
      return isSameDay(cal1, cal2);
  }
}





Checks the day, month and year are equal

   
/*
 * Copyright Javelin Software, All rights reserved.
 */

import java.util.*;
import java.text.*;
/**
 * The DateUtil is used as a Utility Class for Dates.
 * 
 * @author Robin Sharp
 */
public class DateUtil 
{
    public final static long SECOND_MILLIS = 1000;
    public final static long MINUTE_MILLIS = SECOND_MILLIS*60;
    public final static long HOUR_MILLIS = MINUTE_MILLIS*60;
    public final static long DAY_MILLIS = HOUR_MILLIS*24;
    public final static long YEAR_MILLIS = DAY_MILLIS*365;
    public static DateFormat OUT_DATE_FORMAT = new SimpleDateFormat("dd/MM/yyyy");
    public static DateFormat OUT_TIME_FORMAT = new SimpleDateFormat("H:mm:ss");
    public static DateFormat OUT_DATETIME_FORMAT = new SimpleDateFormat("d/M/yyyy H:mm:ss");
    public static DateFormat OUT_TIMESTAMP_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss.SSS");
    
    public static DateFormat IN_DATE_FORMAT = new SimpleDateFormat("d/M/yy");
    public static DateFormat IN_TIME_FORMAT = new SimpleDateFormat("H:mm:ss");
    public static DateFormat IN_DATETIME_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss");
    public static DateFormat IN_TIMESTAMP_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss.SSS");
    
    public static DateFormat DATE_TIME_FORMAT= new SimpleDateFormat( "yyyyMMddkkmmss" );  
    public static Calendar calendar = new GregorianCalendar();
    static
    {
        IN_DATE_FORMAT.setLenient(false);
        IN_TIME_FORMAT.setLenient(false);
        IN_DATETIME_FORMAT.setLenient(false);
    }
    /**
     * Create a new DateTime. To the last second. This will not create any 
     * extra-millis-seconds, which may cause bugs when writing to stores such as
     * databases that round milli-seconds up and down. 
     */
    public static java.util.Date newDateTime()
    {
        return new java.util.Date( (System.currentTimeMillis()/SECOND_MILLIS)*SECOND_MILLIS);
    }
    /**
     * Create a new Date. To the last day.
     */
    public static java.sql.Date newDate()
    {
        return new java.sql.Date( (System.currentTimeMillis()/DAY_MILLIS)*DAY_MILLIS);
    }
    
    /**
     * Create a new Time, with no date component. 
     */
    public static java.sql.Time newTime()
    {
        return new java.sql.Time( System.currentTimeMillis()%DAY_MILLIS);
    }
    
    /**
     * Create a new Timestamp. 
     */
    public static java.sql.Timestamp newTimestamp()
    {
        return new java.sql.Timestamp( System.currentTimeMillis() );
    }
    
    /**
     * Get the seconds difference
     */
    public static int secondsDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/SECOND_MILLIS) - (earlierDate.getTime()/SECOND_MILLIS));
    }
    /**
     * Get the minutes difference
     */
    public static int minutesDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/MINUTE_MILLIS) - (earlierDate.getTime()/MINUTE_MILLIS));
    }
    
    /**
     * Get the hours difference
     */
    public static int hoursDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/HOUR_MILLIS) - (earlierDate.getTime()/HOUR_MILLIS));
    }
    
    /**
     * Get the days difference
     */
    public static int daysDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/DAY_MILLIS) - (earlierDate.getTime()/DAY_MILLIS));
    }
    
   /**
    * Roll the java.util.Time forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.sql.Time rollTime( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.sql.Time(gc.getTime().getTime());
    }
    
   /**
    * Roll the java.util.Date forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.util.Date rollDateTime( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.util.Date(gc.getTime().getTime());
    }
    
   /**
    * Roll the java.sql.Date forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.sql.Date rollDate( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.sql.Date(gc.getTime().getTime());
    }
    
   /**
    * Roll the years forward or backward.
    * @param startDate - The start date
    * @param years - Negative to rollbackwards.
    */
    public static java.sql.Date rollYears( java.util.Date startDate, int years )
    {
        return rollDate( startDate, Calendar.YEAR, years );
    }
   /**
    * Roll the days forward or backward.
    * @param startDate - The start date
    * @param months - Negative to rollbackwards.
    */
    public static java.sql.Date rollMonths( java.util.Date startDate, int months )
    {
        return rollDate( startDate, Calendar.MONTH, months );
    }
   /**
    * Roll the days forward or backward.
    * @param startDate - The start date
    * @param days - Negative to rollbackwards.
    */
    public static java.sql.Date rollDays( java.util.Date startDate, int days )
    {
        return rollDate( startDate, Calendar.DATE, days );
    }
    
     /**
      * Checks the day, month and year are equal.
      */
     public static boolean dateEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;
        
        return d1.getDate() == d2.getDate() &&
               d1.getMonth() == d2.getMonth() &&
               d1.getYear() == d2.getYear();
     }
     
     /**
      * Checks the hour, minute and second are equal.
      */
     public static boolean timeEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;
        
        return d1.getHours() == d2.getHours() &&
               d1.getMinutes() == d2.getMinutes() &&
               d1.getSeconds() == d2.getSeconds();
     }

    /**
      * Checks the second, hour, month, day, month and year are equal.
      */
     public static boolean dateTimeEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;               
        
        return d1.getDate() == d2.getDate() &&
               d1.getMonth() == d2.getMonth() &&
               d1.getYear() == d2.getYear() &&
               d1.getHours() == d2.getHours() &&
               d1.getMinutes() == d2.getMinutes() &&
               d1.getSeconds() == d2.getSeconds();
     }
     
     /**
     * Convert an Object of type Classs to an Object.
     */
    public static Object toObject( Class clazz, Object value ) throws ParseException
    {
        if( value == null ) return null;
        if( clazz == null ) return value;
        
        if( java.sql.Date.class.isAssignableFrom( clazz ) ) return toDate( value );
        if( java.sql.Time.class.isAssignableFrom( clazz ) ) return toTime( value );
        if( java.sql.Timestamp.class.isAssignableFrom( clazz ) ) return toTimestamp( value );
        if( java.util.Date.class.isAssignableFrom( clazz ) ) return toDateTime( value );
        
        return value;
    }
    
    /**
     * Convert an Object to a DateTime, without an Exception
     */
    public static java.util.Date getDateTime( Object value )
    {
        try
        {
            return toDateTime( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    
    /**
     * Convert an Object to a DateTime.
     */
    public static java.util.Date toDateTime( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.util.Date ) return (java.util.Date)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return IN_DATETIME_FORMAT.parse( (String)value );
        }
                
        return IN_DATETIME_FORMAT.parse( value.toString() );
    }
    
    /**
     * Convert an Object to a Date, without an Exception
     */
    public static java.sql.Date getDate( Object value )
    {
        try
        {
            return toDate( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    /**
     * Convert an Object to a Date.
     */
    public static java.sql.Date toDate( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Date ) return (java.sql.Date)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Date( IN_DATE_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Date( IN_DATE_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Convert an Object to a Time, without an Exception
     */
    public static java.sql.Time getTime( Object value )
    {
        try
        {
            return toTime( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    
    /**
     * Convert an Object to a Time.
     */
    public static java.sql.Time toTime( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Time ) return (java.sql.Time)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Time( IN_TIME_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Time( IN_TIME_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Convert an Object to a Timestamp, without an Exception
     */
    public static java.sql.Timestamp getTimestamp( Object value )
    {
        try
        {
            return toTimestamp( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    /**
     * Convert an Object to a Timestamp.
     */
    public static java.sql.Timestamp toTimestamp( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Timestamp ) return (java.sql.Timestamp)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Timestamp( IN_TIMESTAMP_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Timestamp( IN_TIMESTAMP_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Tells you if the date part of a datetime is in a certain time range.
     */
    public static boolean isTimeInRange( java.sql.Time start, java.sql.Time end, java.util.Date d )
    {
        d=new java.sql.Time(d.getHours(),d.getMinutes(),d.getSeconds());
        
        if (start==null || end==null)
        {
            return false;
        }
        
        if (start.before(end)&&(!(d.after(start)&&d.before(end))))
        {
            return false;
        }
        
        if (end.before(start)&&(!(d.after(end)||d.before(start))))
        {
            return false;
        }   
        return true;
    }
    public static  int getYear( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.YEAR );
    }
    public static int getMonth( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MONTH );
    }
    public static int getDate( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.DATE );
    }
    public static int getHour( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.HOUR );
    }
    public static int getMinute( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MINUTE );
    }
    public static int getSeconds( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.SECOND );
    }
    public static int getMillisecond( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MILLISECOND );
    }
    
    /**
     * Convert an Object to a String using Dates
     */
    public static String toString( Object date )
    {
        if( date == null ) return null;
        
        if( java.sql.Timestamp.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_TIMESTAMP_FORMAT.format( date );
        }
        if( java.sql.Time.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_TIME_FORMAT.format( date );
        }
        if( java.sql.Date.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_DATE_FORMAT.format( date );
        }
        if( java.util.Date.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_DATETIME_FORMAT.format( date );
        }
        
        throw new IllegalArgumentException( "Unsupported type " + date.getClass() );
    }
}





Checks the hour, minute and second are equal

   
/*
 * Copyright Javelin Software, All rights reserved.
 */

import java.util.*;
import java.text.*;
/**
 * The DateUtil is used as a Utility Class for Dates.
 * 
 * @author Robin Sharp
 */
public class DateUtil 
{
    public final static long SECOND_MILLIS = 1000;
    public final static long MINUTE_MILLIS = SECOND_MILLIS*60;
    public final static long HOUR_MILLIS = MINUTE_MILLIS*60;
    public final static long DAY_MILLIS = HOUR_MILLIS*24;
    public final static long YEAR_MILLIS = DAY_MILLIS*365;
    public static DateFormat OUT_DATE_FORMAT = new SimpleDateFormat("dd/MM/yyyy");
    public static DateFormat OUT_TIME_FORMAT = new SimpleDateFormat("H:mm:ss");
    public static DateFormat OUT_DATETIME_FORMAT = new SimpleDateFormat("d/M/yyyy H:mm:ss");
    public static DateFormat OUT_TIMESTAMP_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss.SSS");
    
    public static DateFormat IN_DATE_FORMAT = new SimpleDateFormat("d/M/yy");
    public static DateFormat IN_TIME_FORMAT = new SimpleDateFormat("H:mm:ss");
    public static DateFormat IN_DATETIME_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss");
    public static DateFormat IN_TIMESTAMP_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss.SSS");
    
    public static DateFormat DATE_TIME_FORMAT= new SimpleDateFormat( "yyyyMMddkkmmss" );  
    public static Calendar calendar = new GregorianCalendar();
    static
    {
        IN_DATE_FORMAT.setLenient(false);
        IN_TIME_FORMAT.setLenient(false);
        IN_DATETIME_FORMAT.setLenient(false);
    }
    /**
     * Create a new DateTime. To the last second. This will not create any 
     * extra-millis-seconds, which may cause bugs when writing to stores such as
     * databases that round milli-seconds up and down. 
     */
    public static java.util.Date newDateTime()
    {
        return new java.util.Date( (System.currentTimeMillis()/SECOND_MILLIS)*SECOND_MILLIS);
    }
    /**
     * Create a new Date. To the last day.
     */
    public static java.sql.Date newDate()
    {
        return new java.sql.Date( (System.currentTimeMillis()/DAY_MILLIS)*DAY_MILLIS);
    }
    
    /**
     * Create a new Time, with no date component. 
     */
    public static java.sql.Time newTime()
    {
        return new java.sql.Time( System.currentTimeMillis()%DAY_MILLIS);
    }
    
    /**
     * Create a new Timestamp. 
     */
    public static java.sql.Timestamp newTimestamp()
    {
        return new java.sql.Timestamp( System.currentTimeMillis() );
    }
    
    /**
     * Get the seconds difference
     */
    public static int secondsDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/SECOND_MILLIS) - (earlierDate.getTime()/SECOND_MILLIS));
    }
    /**
     * Get the minutes difference
     */
    public static int minutesDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/MINUTE_MILLIS) - (earlierDate.getTime()/MINUTE_MILLIS));
    }
    
    /**
     * Get the hours difference
     */
    public static int hoursDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/HOUR_MILLIS) - (earlierDate.getTime()/HOUR_MILLIS));
    }
    
    /**
     * Get the days difference
     */
    public static int daysDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/DAY_MILLIS) - (earlierDate.getTime()/DAY_MILLIS));
    }
    
   /**
    * Roll the java.util.Time forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.sql.Time rollTime( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.sql.Time(gc.getTime().getTime());
    }
    
   /**
    * Roll the java.util.Date forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.util.Date rollDateTime( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.util.Date(gc.getTime().getTime());
    }
    
   /**
    * Roll the java.sql.Date forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.sql.Date rollDate( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.sql.Date(gc.getTime().getTime());
    }
    
   /**
    * Roll the years forward or backward.
    * @param startDate - The start date
    * @param years - Negative to rollbackwards.
    */
    public static java.sql.Date rollYears( java.util.Date startDate, int years )
    {
        return rollDate( startDate, Calendar.YEAR, years );
    }
   /**
    * Roll the days forward or backward.
    * @param startDate - The start date
    * @param months - Negative to rollbackwards.
    */
    public static java.sql.Date rollMonths( java.util.Date startDate, int months )
    {
        return rollDate( startDate, Calendar.MONTH, months );
    }
   /**
    * Roll the days forward or backward.
    * @param startDate - The start date
    * @param days - Negative to rollbackwards.
    */
    public static java.sql.Date rollDays( java.util.Date startDate, int days )
    {
        return rollDate( startDate, Calendar.DATE, days );
    }
    
     /**
      * Checks the day, month and year are equal.
      */
     public static boolean dateEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;
        
        return d1.getDate() == d2.getDate() &&
               d1.getMonth() == d2.getMonth() &&
               d1.getYear() == d2.getYear();
     }
     
     /**
      * Checks the hour, minute and second are equal.
      */
     public static boolean timeEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;
        
        return d1.getHours() == d2.getHours() &&
               d1.getMinutes() == d2.getMinutes() &&
               d1.getSeconds() == d2.getSeconds();
     }

    /**
      * Checks the second, hour, month, day, month and year are equal.
      */
     public static boolean dateTimeEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;               
        
        return d1.getDate() == d2.getDate() &&
               d1.getMonth() == d2.getMonth() &&
               d1.getYear() == d2.getYear() &&
               d1.getHours() == d2.getHours() &&
               d1.getMinutes() == d2.getMinutes() &&
               d1.getSeconds() == d2.getSeconds();
     }
     
     /**
     * Convert an Object of type Classs to an Object.
     */
    public static Object toObject( Class clazz, Object value ) throws ParseException
    {
        if( value == null ) return null;
        if( clazz == null ) return value;
        
        if( java.sql.Date.class.isAssignableFrom( clazz ) ) return toDate( value );
        if( java.sql.Time.class.isAssignableFrom( clazz ) ) return toTime( value );
        if( java.sql.Timestamp.class.isAssignableFrom( clazz ) ) return toTimestamp( value );
        if( java.util.Date.class.isAssignableFrom( clazz ) ) return toDateTime( value );
        
        return value;
    }
    
    /**
     * Convert an Object to a DateTime, without an Exception
     */
    public static java.util.Date getDateTime( Object value )
    {
        try
        {
            return toDateTime( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    
    /**
     * Convert an Object to a DateTime.
     */
    public static java.util.Date toDateTime( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.util.Date ) return (java.util.Date)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return IN_DATETIME_FORMAT.parse( (String)value );
        }
                
        return IN_DATETIME_FORMAT.parse( value.toString() );
    }
    
    /**
     * Convert an Object to a Date, without an Exception
     */
    public static java.sql.Date getDate( Object value )
    {
        try
        {
            return toDate( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    /**
     * Convert an Object to a Date.
     */
    public static java.sql.Date toDate( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Date ) return (java.sql.Date)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Date( IN_DATE_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Date( IN_DATE_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Convert an Object to a Time, without an Exception
     */
    public static java.sql.Time getTime( Object value )
    {
        try
        {
            return toTime( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    
    /**
     * Convert an Object to a Time.
     */
    public static java.sql.Time toTime( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Time ) return (java.sql.Time)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Time( IN_TIME_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Time( IN_TIME_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Convert an Object to a Timestamp, without an Exception
     */
    public static java.sql.Timestamp getTimestamp( Object value )
    {
        try
        {
            return toTimestamp( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    /**
     * Convert an Object to a Timestamp.
     */
    public static java.sql.Timestamp toTimestamp( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Timestamp ) return (java.sql.Timestamp)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Timestamp( IN_TIMESTAMP_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Timestamp( IN_TIMESTAMP_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Tells you if the date part of a datetime is in a certain time range.
     */
    public static boolean isTimeInRange( java.sql.Time start, java.sql.Time end, java.util.Date d )
    {
        d=new java.sql.Time(d.getHours(),d.getMinutes(),d.getSeconds());
        
        if (start==null || end==null)
        {
            return false;
        }
        
        if (start.before(end)&&(!(d.after(start)&&d.before(end))))
        {
            return false;
        }
        
        if (end.before(start)&&(!(d.after(end)||d.before(start))))
        {
            return false;
        }   
        return true;
    }
    public static  int getYear( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.YEAR );
    }
    public static int getMonth( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MONTH );
    }
    public static int getDate( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.DATE );
    }
    public static int getHour( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.HOUR );
    }
    public static int getMinute( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MINUTE );
    }
    public static int getSeconds( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.SECOND );
    }
    public static int getMillisecond( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MILLISECOND );
    }
    
    /**
     * Convert an Object to a String using Dates
     */
    public static String toString( Object date )
    {
        if( date == null ) return null;
        
        if( java.sql.Timestamp.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_TIMESTAMP_FORMAT.format( date );
        }
        if( java.sql.Time.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_TIME_FORMAT.format( date );
        }
        if( java.sql.Date.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_DATE_FORMAT.format( date );
        }
        if( java.util.Date.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_DATETIME_FORMAT.format( date );
        }
        
        throw new IllegalArgumentException( "Unsupported type " + date.getClass() );
    }
}





Compare two dates

  
/**
 * Copyright (c) 2003 - 2007 OpenSubsystems s.r.o. Slovak Republic. All rights reserved.
 * 
 * Project: OpenSubsystems
 * 
 * $Id: DateUtils.java,v 1.7 2007/01/07 06:14:00 bastafidli Exp $
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License. 
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
 */

import java.sql.Timestamp;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;

/**
 * Collection of useful utilities to work with dates. 
 * 
 * @version $Id: DateUtils.java,v 1.7 2007/01/07 06:14:00 bastafidli Exp $
 * @author Miro Halas
 * @code.reviewer Miro Halas
 * @code.reviewed 1.5 2005/09/13 13:23:15 bastafidli
 */
public final class DateUtils
{
   // Constants ////////////////////////////////////////////////////////////////
   
   /**
    * One second in milliseconds.
    */
   public static final long ONE_SECOND = 1000L;
   
   /**
    * One minute in milliseconds.
    */
   public static final long ONE_MINUTE = ONE_SECOND * 60L;
   
   /**
    * One hour in milliseconds.
    */
   public static final long ONE_HOUR = ONE_MINUTE * 60L;
   
   /**
    * One day in milliseconds.
    */
   public static final long ONE_DAY = ONE_HOUR * 24L;
   
   /**
    * Separator we used to separate time from the nanosecond portion of the 
    * timestamp when converted to string.
    */
   public static final char NANO_SEPARATOR = ":";
   
   /**
    * Constant for timing type
    */
   public static final int TIMING_NEVER = 0;
   /**
    * Constant for timing type
    */
   public static final int TIMING_MINUTES = 1;
   /**
    * Constant for timing type
    */
   public static final int TIMING_HOURS = 2;
   /**
    * Constant for timing type
    */
   public static final int TIMING_DAYS = 3;
   /**
    * Constant for timing type
    */
   public static final int TIMING_WEEKS = 4;
   /**
    * Constant for timing type
    */
   public static final int TIMING_MONTHS = 5;
   /**
    * Constant for timing type
    */
   public static final int TIMING_YEARS = 6;
   
   /**
    * Constant for timing type
    */
   public static final int TIMING_NONE = 7;
   /**
    * Constant for current date code used in date/time formulas 
    */
   public static final String CURRENT_DATE_CODE = "now";
   
   /**
    * Constant for dynamic date code used in date/time formulas
    */
   public static final char YEAR_CODE = "y";
   
   /**
    * Constant for dynamic date code used in date/time formulas
    */
   public static final char MONTH_CODE = "M";
   /**
    * Constant for dynamic date code used in date/time formulas
    */
   public static final char WEEK_CODE = "w";
   /**
    * Constant for dynamic date code used in date/time formulas
    */
   public static final char DAY_CODE = "d";
   /**
    * Constant for dynamic date code used in date/time formulas
    */
   public static final char HOUR_CODE = "h";
   /**
    * Constant for dynamic date code used in date/time formulas
    */
   public static final char MINUTE_CODE = "m";
   
   /**
    * Constant for dynamic date code used in date/time formulas
    */
   public static final char SECOND_CODE = "s";
   /**
    * constant for date type DATE
    */
   public static final int DATE_TYPE_DATE = 1;
   /**
    * constant for date type TIME
    */
   public static final int DATE_TYPE_TIME = 2;
   /**
    * constant for date type DATETIME
    */
   public static final int DATE_TYPE_DATETIME = 3;
   
   // Constants for period start types /////////////////////////////////////////
// TODO: For Miro: Remove this code once all the code which referred to these
// constants was fixed
//   /**
//    * constant for period type
//    */
//   public static final int PERIOD_START_TYPE_NONE = 0;
//
//   /**
//    * constant for period type
//    */
//   public static final int PERIOD_START_TYPE_CREATION = 1;
//
//   /**
//    * constant for period type
//    */
//   public static final int PERIOD_START_TYPE_COMPLETION = 2;
//
//   /**
//    * constant for period type
//    */
//   public static final int PERIOD_START_TYPE_APPROVAL = 3;
//
//   /**
//    * constant for period type
//    */
//   public static final int PERIOD_START_TYPE_ACTIVATION = 4;
//
//   /**
//    * constant for period type
//    */
//   public static final int PERIOD_START_TYPE_INACTIVATION = 5;
//   
//   /**
//    * constant for period type
//    */
//   public static final int PERIOD_START_TYPE_DYNAMIC = 6;
//
//   /**
//    * constant for period type code
//    */
//   public static final int PERIOD_TYPE_CODE = 99;
//
//   /**
//    * constant for period type object
//    */
//   public static final Integer PERIOD_TYPE_OBJ = new Integer(PERIOD_TYPE_CODE);
   // Cached variables /////////////////////////////////////////////////////////
   
   /**
    * static SimpleDateFormat for date format to display on UI and in messages.
    */
   public static final SimpleDateFormat DATE_FORMAT 
                          = (SimpleDateFormat) DateFormat.getDateInstance(DateFormat.SHORT);
   
   /**
    * static SimpleDateFormat for time format to display on UI and in messages.
    */
   public static final SimpleDateFormat TIME_FORMAT 
                          = (SimpleDateFormat) DateFormat.getTimeInstance(DateFormat.MEDIUM);
   
   /**
    * static SimpleDateFormat for datetime format to display on UI and in messages.
    */
   public static final SimpleDateFormat DATETIME_FORMAT 
                          = (SimpleDateFormat) DateFormat.getDateTimeInstance(DateFormat.SHORT, 
                                                           DateFormat.MEDIUM); 
   /**
    * static SimpleDateFormat for date format to store date as string so that
    * it is stored consistently.
    */
   public static final SimpleDateFormat DATE_STORE_FORMAT
                          = new SimpleDateFormat("MM/dd/yyyy");
   
   /**
    * static SimpleDateFormat for time format to store time as string so that
    * it is stored consistently.
    */
   public static final SimpleDateFormat TIME_STORE_FORMAT 
                          = new SimpleDateFormat("HH:mm:ss");
   
   /**
    * static SimpleDateFormat for datetime format to store date and time as 
    * string so that it is stored consistently.
    */
   public static final SimpleDateFormat DATETIME_STORE_FORMAT 
                          = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss");

   /**
    * static SimpleDateFormat for date format for sql date
    */
   public static final SimpleDateFormat DATE_SQL_FORMAT
                          = new SimpleDateFormat("yyyy-MM-dd 00:00:00");
   
   /**
    * static SimpleDateFormat for time format for sql time
    */
   public static final SimpleDateFormat TIME_SQL_FORMAT 
                          = new SimpleDateFormat("1970-01-01 HH:mm:ss");
   
   /**
    * static SimpleDateFormat for datetime format for sql date and time
    */
   public static final SimpleDateFormat DATETIME_SQL_FORMAT 
                          = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
   // Constructors /////////////////////////////////////////////////////////////
   
   /** 
    * Private constructor since this class cannot be instantiated
    */
   private DateUtils(
   )
   {
      // Do nothing
   }
   
   // Public methods ///////////////////////////////////////////////////////////
   
   /**
    * Check if two dates equals regardless of the time. Two null dates are equal. 
    * Null and not null dates are not equal.
    * 
    * @param  dtFirst - first date to compare, can be null
    * @param  dtSecond - second date to compare, can be null 
    * @return boolean - true if two dates equals regardless of what the time is 
    */
   public static boolean dateEquals(
      Date dtFirst,
      Date dtSecond
   )
   {
      boolean  bReturn = false;
      
      // If they are the same object, they are equals
      bReturn = (dtFirst == dtSecond);
      if (!bReturn)
      {
         if (dtFirst == null)
         {
            // Two null dates are the same
            bReturn = (dtSecond == null);
         }
         else
         {
            if (dtSecond != null)
            {
               Calendar compCalendar;
               int      iEra;
               int      iYear;
               int      iMonth;
               int      iDay;
               
               compCalendar = Calendar.getInstance();
               compCalendar.setTime(dtFirst);
               iEra   = compCalendar.get(Calendar.ERA);
               iYear  = compCalendar.get(Calendar.YEAR);
               iMonth = compCalendar.get(Calendar.MONTH);
               iDay   = compCalendar.get(Calendar.DATE);
               compCalendar.setTime(dtSecond);
         
               bReturn = ((iEra == compCalendar.get(Calendar.ERA))
                         && (iYear == compCalendar.get(Calendar.YEAR))
                         && (iMonth == compCalendar.get(Calendar.MONTH))
                         && (iDay == compCalendar.get(Calendar.DATE)));
            }
         }
      } 
            
      return bReturn;            
   }
   
   /**
    * Check if two times equals regardless of the date. Two null times are equal. 
    * Null and not null times are not equal.
    * 
    * @param  dtFirst - first time to compare, can be null
    * @param  dtSecond - second time to compare, can be null
    * @param  bIgnoreMilliseconds - if true milliseconds will be ignored in comparison
    * @return boolean - true if two time equals regardless of what the date is 
    */
   public static boolean timeEquals(
      Date    dtFirst,
      Date    dtSecond,
      boolean bIgnoreMilliseconds
   )
   {
      boolean  bReturn = false;
      
      // If they are the same object, they are equals
      bReturn = (dtFirst == dtSecond);
      if (!bReturn)
      {
         if (dtFirst == null)
         {
            // Two null dates are the same
            bReturn = (dtSecond == null);
         }
         else
         {
            if (dtSecond != null)
            {
               Calendar compCalendar;
               int      iHour;
               int      iMinute;
               int      iSecond;
               int      iMili;
               
               compCalendar = Calendar.getInstance();
               compCalendar.setTime(dtFirst);
               iHour   = compCalendar.get(Calendar.HOUR_OF_DAY);
               iMinute = compCalendar.get(Calendar.MINUTE);
               iSecond = compCalendar.get(Calendar.SECOND);
               iMili   = compCalendar.get(Calendar.MILLISECOND);
               compCalendar.setTime(dtSecond);
         
               bReturn = ((iHour == compCalendar.get(Calendar.HOUR_OF_DAY))
                         && (iMinute == compCalendar.get(Calendar.MINUTE))
                         && (iSecond == compCalendar.get(Calendar.SECOND))
                         && ((bIgnoreMilliseconds) 
                            || (iMili == compCalendar.get(Calendar.MILLISECOND))));
            }
         }
      } 
            
      return bReturn;            
   }
   /**
    * Check if two dates and times are equal. Two null dates are equal. Null 
    * and not null dates are not equal.
    * 
    * @param  dtFirst - first date time to compare, can be null
    * @param  dtSecond - second date time to compare, can be null
    * @return boolean - true if two date and times are equal 
    */
   public static boolean dateAndTimeEquals(
      Date dtFirst,
      Date dtSecond
   )
   {
      boolean bReturn = false;
      
      // If they are the same object, they are equals
      bReturn = (dtFirst == dtSecond);
      if (!bReturn)
      {
         if (dtFirst == null)
         {
            // Two null dates are the same
            bReturn = (dtSecond == null);
         }
         else
         {
            if (dtSecond != null)
            {
               // They are both not null so they have to match to millisecond
               // (actually to nanosecond since the getTime takes nanoseconds
               // into account)
               bReturn = (dtFirst.getTime() == dtSecond.getTime());                               
            }
         }
      }
            
      return bReturn;            
   }
   /**
    * Check if String representing date is function or date. Date is a function
    * (formula) if it starts with the current date/time variable which can be 
    * followed by expression describing period from current date.
    *
    * @param strValue - string representation of date or date function
    * @return boolean - date function flag
    */
   public static boolean isFunction(
      String   strValue
   )
   {
      boolean bReturn = false;
      if ((strValue != null) && (strValue.length() > 0) 
         && (strValue.trim().startsWith(CURRENT_DATE_CODE)))
      {
         bReturn = true;
      }
      
      return bReturn;
   }
   
   /**
    * Parse date time value from given string resolving any functions or formulas
    * the string can contain. This method  can be therefore used if the passed 
    * string contains string representation date, time or timestamp or a formula
    * such as now + 3h - 1m + 4d. 
    *
    * @param strValue - string representation of date or date function
    * @param iDateType - date type code, one of the DATE_TYPE_XXX constants
    * @param stored - flag if Date should be parsed using format used for 
    *                 storage or for display
    * @return Timestamp - parsed date or null if date was null
    * @throws OSSInvalidDataException - error during parsing
    */
   public static Timestamp parseDateTime(
      String   strValue,
      int      iDateType,
      boolean  stored
   )
   {
      Timestamp tsReturn = null;
      Calendar workCal = GregorianCalendar.getInstance();
      
      if (strValue != null && strValue.length() > 0)
      {
         strValue = strValue.trim();
         if (strValue.startsWith(CURRENT_DATE_CODE))
         {
            strValue = strValue.replaceAll("[ ]", "");
            // If the user specified "UseCurrent", then substitute the
            // current date/time in the value
            workCal.setTime(new Date());
//            Log.getInstance().debug("Parsing current date " + strValue);
            // Parse the date math
            int iBeginIndex = CURRENT_DATE_CODE.length();
            int iMaxLength = strValue.length();
            int iSign = 1;
            int iNumberIndex;
            int iValue;
            char cChar = " ";
            while (iBeginIndex < iMaxLength)
            {
               // This has to be sign
               if (strValue.charAt(iBeginIndex) == "+")
               {
                  iSign = 1;
               }
               else if (strValue.charAt(iBeginIndex) == "-")
               {
                  iSign = -1;
               }
               else
               {
                  // Incorrect String
                  throw new RuntimeException(
                           "Date function is in incorrect format: "
                           + strValue + " at " + strValue.substring(iBeginIndex));
               }
               iBeginIndex++;
               // Now we have to have number
               iNumberIndex = iBeginIndex;
               
               while (((iBeginIndex == iNumberIndex) || Character.isDigit(cChar)) 
                     && (iBeginIndex < iMaxLength))
               {
                  cChar = strValue.charAt(iBeginIndex++);
               }
               // We have to go one back because we should stop on modifier (e.g 1m)
               iBeginIndex--;
               try
               {
                  iValue = Integer.parseInt(strValue.substring(iNumberIndex, iBeginIndex));
               }
               catch (NumberFormatException nmeExc)
               {
                  // Incorrect String
                  throw new RuntimeException(
                           "Date function is in incorrect format: "
                           + strValue + " at " + strValue.substring(iNumberIndex));
               }
               // This has to be modifier: y - year, M - month, w - week, 
               // d - day, h - hour, m - minute, s - second
               cChar = strValue.charAt(iBeginIndex);
               switch(cChar)
               {
                  case(YEAR_CODE):
                  {
                     if (iDateType == DATE_TYPE_TIME)
                     {
                        throw new RuntimeException(
                           "Date function is in incorrect format: " +
                           "used YEAR modifier for TIME type");
                     }
                     workCal.add(Calendar.YEAR, iSign * iValue);
                     break;
                  }
                  case(MONTH_CODE):
                  {
                     if (iDateType == DATE_TYPE_TIME)
                     {
                        throw new RuntimeException(
                           "Date function is in incorrect format: " +
                           "used MONTH modifier for TIME type");
                     }
                     workCal.add(Calendar.MONTH, iSign * iValue);
                     break;
                  }
                  case(WEEK_CODE):
                  {
                     if (iDateType == DATE_TYPE_TIME)
                     {
                        throw new RuntimeException(
                           "Date function is in incorrect format: " +
                           "used WEEK modifier for TIME type");
                     }
                     workCal.add(Calendar.WEEK_OF_YEAR, iSign * iValue);
                     break;
                  }
                  case(DAY_CODE):
                  {
                     if (iDateType == DATE_TYPE_TIME)
                     {
                        throw new RuntimeException(
                           "Date function is in incorrect format: " +
                           "used DAY modifier for TIME type");
                     }
                     workCal.add(Calendar.DATE, iSign * iValue);
                     break;
                  }
                  case(HOUR_CODE):
                  {
                     if (iDateType == DATE_TYPE_DATE)
                     {
                        throw new RuntimeException(
                           "Date function is in incorrect format: " +
                           "used HOUR modifier for DATE type");
                     }
                     workCal.add(Calendar.HOUR, iSign * iValue);
                     break;
                  }
                  case(MINUTE_CODE):
                  {
                     if (iDateType == DATE_TYPE_DATE)
                     {
                        throw new RuntimeException(
                           "Date function is in incorrect format: " +
                           "used MINUTE modifier for DATE type");
                     }
                     workCal.add(Calendar.MINUTE, iSign * iValue);
                     break;
                  }
                  case(SECOND_CODE):
                  {
                     if (iDateType == DATE_TYPE_DATE)
                     {
                        throw new RuntimeException(
                           "Date function is in incorrect format: " +
                           "used SECOND modifier for DATE type");
                     }
                     workCal.add(Calendar.SECOND, iSign * iValue);
                     break;
                  }
                  default:
                  {
                     // Incorrect String
                     throw new RuntimeException(
                           "Date function is in incorrect format: "
                           + strValue + " at " + strValue.substring(iBeginIndex));
                  }
               }
               iBeginIndex++;
            }
            
            tsReturn = new Timestamp(workCal.getTimeInMillis());
            
         }
         else
         {
            try
            {
               if (stored)
               {
                  switch (iDateType)
                  {
                     case (DATE_TYPE_DATE) :
                     {
                        tsReturn = new Timestamp(DATE_STORE_FORMAT.parse(strValue).getTime());
                        break;   
                     }
                     case (DATE_TYPE_TIME) :
                     {
                        tsReturn = new Timestamp(TIME_STORE_FORMAT.parse(strValue).getTime());
                        break;   
                     }
                     case (DATE_TYPE_DATETIME) :
                     {
                        tsReturn = new Timestamp(DATETIME_STORE_FORMAT.parse(strValue).getTime());
                        break;   
                     }
                     default:
                     {
                        assert false : "Unknown date type " + iDateType;
                     }
                  }                  
               }
               else
               {
                  switch (iDateType)
                  {
                     case (DATE_TYPE_DATE) :
                     {
                        tsReturn = new Timestamp(DATE_FORMAT.parse(strValue).getTime());
                        break;   
                     }
                     case (DATE_TYPE_TIME) :
                     {
                        tsReturn = new Timestamp(TIME_FORMAT.parse(strValue).getTime());
                        break;   
                     }
                     case (DATE_TYPE_DATETIME) :
                     {
                        tsReturn = new Timestamp(DATETIME_FORMAT.parse(strValue).getTime());
                        break;   
                     }
                     default:
                     {
                        assert false : "Unknown date type " + iDateType;
                     }                  
                  }                  
               }
            }
            catch (ParseException peExc)
            {
               throw new RuntimeException(
                     "Date is in incorrect format. Problems with parsing.",
                     peExc);
            }
         }
      }
      return tsReturn;
   }
   
   /**
    * Parse the specified period into string displaying number of days the 
    * period represents. 
    * 
    * @param lPeriod - period in miliseconds
    * @return String - period in format "x day(s)" or "" if not valid period
    */
   public static String parseDayPeriod(
      long lPeriod
   )
   {
      StringBuffer sbReturn = new StringBuffer();
      long lDays = 0L;
      
      if (lPeriod > 0)
      {
         // we will count each started day as counted day 
         lPeriod = lPeriod + DateUtils.ONE_DAY - 1;
         
         lDays = lPeriod / DateUtils.ONE_DAY;
         sbReturn.append(lDays);
         if (lDays == 1L)
         {
            sbReturn.append(" day");
         }
         else
         {
            sbReturn.append(" days");
         }
      }
      else
      {
         sbReturn.append("0 days");
      }
      return sbReturn.toString();
   }
   
   /**
    * Parse the specified period into string displaying date and time the 
    * period represents. 
    * 
    * @param lPeriod - preiod in miliseconds
    * @return String - period in format "x day(s) y hour(s) z minute(s)" 
    *                  or "" if not valid period
    */
   public static String parseDayTimePeriod(
      long lPeriod
   )
   {
      StringBuffer sbReturn = new StringBuffer();
      long lHelp = 0L;
      
      
      if (lPeriod > 0)
      {
         lPeriod = lPeriod + DateUtils.ONE_MINUTE - 1;
         // we will count each started day as counted day 
         lHelp = lPeriod / DateUtils.ONE_DAY;
         if (lHelp > 0)
         {
            sbReturn.append(lHelp);
            if (lHelp == 1L)
            {
               sbReturn.append(" d ");
            }
            else
            {
               sbReturn.append(" d ");
            }
         }
         lPeriod = lPeriod % DateUtils.ONE_DAY;
         lHelp = lPeriod / DateUtils.ONE_HOUR;
         if (lHelp > 0 || sbReturn.length() > 0)
         {
            sbReturn.append(lHelp);
            if (lHelp == 1L)
            {
               sbReturn.append(" h ");
            }
            else
            {
               sbReturn.append(" h ");
            }
         }
         lPeriod = lPeriod % DateUtils.ONE_HOUR;
         lHelp = lPeriod / DateUtils.ONE_MINUTE;
         if (lHelp > 0 || sbReturn.length() > 0)
         {
            sbReturn.append(lHelp);
            if (lHelp == 1L)
            {
               sbReturn.append(" min");
            }
            else
            {
               sbReturn.append(" min");
            }
         }
      }
      else
      {
         sbReturn.append("0 min");
      }
      return sbReturn.toString();
   }
   
// TODO: For Miro: Remove this code once all the code which referred to these
// was fixed. These should be moved to a GUI related class.
//   /**
//    * Method for list of timing types.
//    * 
//    * @return List - list of timing types
//    */
//   public static List getTimingTypes(
//   )
//   { 
//      List lstTimingTypes = new ArrayList();
//      
//      lstTimingTypes.add(new SelectOption(Integer.toString(DateUtils.TIMING_MINUTES), 
//                                                           "Minute(s)"));
//      lstTimingTypes.add(new SelectOption(Integer.toString(DateUtils.TIMING_HOURS), "Hour(s)"));
//      lstTimingTypes.add(new SelectOption(Integer.toString(DateUtils.TIMING_DAYS), "Day(s)"));
//      lstTimingTypes.add(new SelectOption(Integer.toString(DateUtils.TIMING_WEEKS), "Week(s)"));
//      lstTimingTypes.add(new SelectOption(Integer.toString(DateUtils.TIMING_MONTHS), "Month(s)"));
//      lstTimingTypes.add(new SelectOption(Integer.toString(DateUtils.TIMING_YEARS), "Year(s)"));
//      lstTimingTypes.add(new SelectOption(Integer.toString(DateUtils.TIMING_NEVER), "Never"));
//      
//      return lstTimingTypes;
//   }
//   /**
//    * Method for list of timing types with None option.
//    * 
//    * @return List - list of timing types
//    */
//   public static List getTimingTypesWithNone(
//   )
//   { 
//      List lstTimingTypes = new ArrayList();
//      
//      lstTimingTypes.add(new SelectOption(Integer.toString(DateUtils.TIMING_NONE), "None"));
//      lstTimingTypes.add(new SelectOption(Integer.toString(DateUtils.TIMING_MINUTES), 
//                         "Minute(s)"));
//      lstTimingTypes.add(new SelectOption(Integer.toString(DateUtils.TIMING_HOURS), "Hour(s)"));
//      lstTimingTypes.add(new SelectOption(Integer.toString(DateUtils.TIMING_DAYS), "Day(s)"));
//      lstTimingTypes.add(new SelectOption(Integer.toString(DateUtils.TIMING_WEEKS), "Week(s)"));
//      lstTimingTypes.add(new SelectOption(Integer.toString(DateUtils.TIMING_MONTHS), "Month(s)"));
//      lstTimingTypes.add(new SelectOption(Integer.toString(DateUtils.TIMING_YEARS), "Year(s)"));
//      lstTimingTypes.add(new SelectOption(Integer.toString(DateUtils.TIMING_NEVER), "Never"));
//      
//      return lstTimingTypes;
//   }
//   /**
//    * Method for getting string name of the timing type.
//    * 
//    * @param iTimingType - timing type constant
//    * @return String - string name of timing type
//    */
//   public static String getTimingTypeName(
//      int iTimingType
//   )
//   {
//      String outTimingTypeName = "Never"; 
//      switch (iTimingType)      
//      {
//         case (DateUtils.TIMING_NEVER):
//         {
//            outTimingTypeName = "Never";
//            break;
//         }
//         case (DateUtils.TIMING_MINUTES):
//         {
//            outTimingTypeName = "Minute(s)";
//            break;
//         }
//         case (DateUtils.TIMING_HOURS):
//         {
//            outTimingTypeName = "Hour(s)";
//            break;
//         }
//         case (DateUtils.TIMING_DAYS):
//         {
//            outTimingTypeName = "Day(s)";
//            break;
//         }
//         case (DateUtils.TIMING_WEEKS):
//         {
//            outTimingTypeName = "Week(s)";
//            break;
//         }
//         case (DateUtils.TIMING_MONTHS):
//         {
//            outTimingTypeName = "Month(s)";
//            break;
//         }
//         case (DateUtils.TIMING_YEARS):
//         {
//            outTimingTypeName = "Year(s)";
//            break;
//         }
//         case (DateUtils.TIMING_NONE):
//         {
//            outTimingTypeName = "None";
//            break;
//         }
//      }
//
//      return outTimingTypeName;
//   }
   
   /**
    * Get expiration timestamp from start date, period type and duration. For 
    * example if the start date is now, period type is hour and duration is 2
    * then the result will be timestamp representing now + 2 hours.  
    * 
    * @param tsStartDate - start date of period counting
    * @param iPeriodType - one of the period type constant TIMING_XXX 
    * @param iPeriodDuration - period duration, number of time units specified 
    *                          by period type
    * @return Timestamp - date of period expiration or null if any problem
    */
   public static Timestamp getPeriodExpiration(
      Timestamp tsStartDate,
      int       iPeriodType,
      int       iPeriodDuration
   )
   {
      Timestamp tsReturn = null;
      Calendar calHelp;
      if (tsStartDate != null && iPeriodDuration > 0 
            && iPeriodType > TIMING_NEVER && iPeriodType < TIMING_NONE)
      {
         calHelp = Calendar.getInstance();
         calHelp.setTime(tsStartDate);
         
         switch (iPeriodType)
         {
            case (TIMING_MINUTES) :
            {
               calHelp.add(Calendar.MINUTE, iPeriodDuration);
               break;
            }
            case (TIMING_HOURS) :
            {
               calHelp.add(Calendar.HOUR, iPeriodDuration);
               break;
            }
            case (TIMING_DAYS) :
            {
               calHelp.add(Calendar.DATE, iPeriodDuration);
               break;
            }
            case (TIMING_WEEKS) :
            {
               calHelp.add(Calendar.WEEK_OF_YEAR, iPeriodDuration);
               break;
            }
            case (TIMING_MONTHS) :
            {
               calHelp.add(Calendar.MONTH, iPeriodDuration);
               break;
            }
            case (TIMING_YEARS) :
            {
               calHelp.add(Calendar.YEAR, iPeriodDuration);
               break;
            }
            default :
            {
               assert false : "Not supported Timing type " + iPeriodType;
            } 
         }
         tsReturn = new Timestamp(calHelp.getTimeInMillis());
      }
      
      return tsReturn;
   }
   
   /**
    * Method to compare time periods
    * 
    * @param iPeriodType1 - first period type, one of the period type constant 
    *                       TIMING_XXX
    * @param iPeriodDuration1 - first period duration
    * @param iPeriodType2 - second period type, one of the period type constant 
    *                       TIMING_XXX
    * @param iPeriodDuration2 - second period duration
    * @return int - 1 - first period is longer
    *               0 - periods are same
    *              -1 - first period is shorter
    */
   public static int comparePeriods(
      int iPeriodType1,
      int iPeriodDuration1,
      int iPeriodType2,
      int iPeriodDuration2
   )
   {
      int iReturn = 0;
      
      if ((iPeriodType1 != TIMING_NEVER) && (iPeriodType1 != TIMING_NONE) 
         && (iPeriodType2 != TIMING_NEVER) && (iPeriodType2 != TIMING_NONE))
      {
         Timestamp tsTimestamp1 = getPeriodExpiration(
               new Timestamp(0), iPeriodType1, iPeriodDuration1);
         Timestamp tsTimestamp2 = getPeriodExpiration(
               new Timestamp(0), iPeriodType2, iPeriodDuration2);
         
         // TODO: Improve: When would any of these be null?
         if ((tsTimestamp1 != null) && (tsTimestamp2 != null))
         {
            if (tsTimestamp1.after(tsTimestamp2))
            {
               iReturn = 1;
            }
            else if (tsTimestamp2.after(tsTimestamp1))
            {
               iReturn = -1;
            }
         }
      }
      else
      {
         if (iPeriodType1 != iPeriodType2)
         {
            if (iPeriodType1 == TIMING_NEVER)
            {
               iReturn = 1;
            }
            else if (iPeriodType1 == TIMING_NONE)
            {
               iReturn = -1;
            }
            else if (iPeriodType2 == TIMING_NEVER)
            {
               iReturn = -1;
            }
            else if (iPeriodType2 == TIMING_NONE)
            {
               iReturn = 1;
            }
         }
      }
      return iReturn;      
   }
   
   /**
    * Convert timestamp to string including it"s nanosecond portion so that it 
    * can be safely stored in variable of web page.
    * 
    * @param tsTimestamp - timestamp to convert
    * @return String - text containing time and nanosecond portion of timestamp
    */
   public static String getTimestampAsString(
      Timestamp tsTimestamp
   )
   {
      StringBuffer sbTimestamp = new StringBuffer();
      
      sbTimestamp.append(tsTimestamp.getTime());
      sbTimestamp.append(NANO_SEPARATOR);
      sbTimestamp.append(tsTimestamp.getNanos());
      
      return sbTimestamp.toString();
   }
   

   /**
    * Function returns time string in the form MM:SS.MS from the input specified in miliseconds. 
    * 
    * @param lTimeInMiliseconds - time in miliseconds
    * @return String - string representation of miliseconds in the form MM:SS.MS
    */
   public static String getStringTime(
      long lTimeInMiliseconds
   )
   {
      long lTotalMS   = lTimeInMiliseconds;
      long lMS        = lTotalMS % 1000;
      long lTotalSecs = lTotalMS / 1000;
      long lSecs      = lTotalSecs % 60;
      long lTotalMins = lTotalSecs / 60;
      long lMinutes   = lTotalMins % 60;
      long lHours     = lTotalMins / 60;
      StringBuffer sbBuffer = new StringBuffer();
      if (lHours > 0)
      {
         sbBuffer.append(lHours);
         sbBuffer.append(":");
         sbBuffer.append(lMinutes);
         sbBuffer.append(":");
         sbBuffer.append(lSecs);
         sbBuffer.append(".");
         sbBuffer.append(lMS);
      }
      else if (lMinutes > 0)
      {
         sbBuffer.append(lMinutes);
         sbBuffer.append(":");
         sbBuffer.append(lSecs);
         sbBuffer.append(".");
         sbBuffer.append(lMS);
      }
      else if (lSecs > 0)
      {
         sbBuffer.append(lSecs);
         sbBuffer.append(".");
         sbBuffer.append(lMS);
         sbBuffer.append(" seconds");
      }
      else
      {
         sbBuffer.append(lMS);
         sbBuffer.append(" ms");
      }
      
      return sbBuffer.toString();
   }
// TODO: For Miro: Remove this code once all the code which referred to these
// was fixed. These should be moved to a GUI or business logic related class.
//   /**
//    * Method to check if valid period settings
//    * 
//    * @param iPeriod - period length
//    * @param iPeriodType - period type
//    * @param iPeriodStartType - period start type
//    * @param iAttributeId - attribute ID for dynamic period start type
//    * @param bPeriodException - period exception flag
//    * @param strPeriodName - period name used for exception message
//    * @param bAdvancePeriodType - flag if advanced period type (includes also start type)
//    * @param bfideException - invalid data exception
//    */
//   public static void validatePeriod(
//      int iPeriod,
//      int iPeriodType,
//      int iPeriodStartType,
//      int iAttributeId,
//      boolean bPeriodException,
//      String strPeriodName,
//      boolean bAdvancePeriodType,
//      OSSInvalidDataException messageException
//   ) 
//   {
//      if ((iPeriod > 0) 
//         || ((iPeriodType != TIMING_NONE) && (iPeriodType != TIMING_NEVER)) 
//         || (bPeriodException) || (iPeriodStartType != PERIOD_START_TYPE_NONE))
//      {
//         if (iPeriod <= 0)
//         {
//            if (messageException == null)
//            {
//               messageException = new OSSInvalidDataException();
//            }
//            messageException.getErrorMessages().addMessage(
//               PERIOD_TYPE_OBJ, 
//               "You have to set valid period length for " + strPeriodName + " type."
//            );
//         }
//         else if ((iPeriodType == TIMING_NONE) || (iPeriodType == TIMING_NEVER))
//         {
//            if (messageException == null)
//            {
//               messageException = new OSSInvalidDataException();
//            }
//            messageException.getErrorMessages().addMessage(
//               PERIOD_TYPE_OBJ, 
//               "You have to set valid period type for " + strPeriodName + " type."
//            );
//         }
//         else if ((bAdvancePeriodType) && (iPeriodStartType == PERIOD_START_TYPE_NONE))
//         {
//            if (messageException == null)
//            {
//               messageException = new OSSInvalidDataException();
//            }
//            messageException.getErrorMessages().addMessage(
//               PERIOD_TYPE_OBJ, 
//               "You have to set valid period start type for " + strPeriodName + " type."
//            );
//         }
//         else if ((bAdvancePeriodType) 
//                 && (iPeriodStartType == PERIOD_START_TYPE_DYNAMIC) 
//                 && (iAttributeId == DataObject.NEW_ID))
//         {
//            if (messageException == null)
//            {
//               messageException = new OSSInvalidDataException();
//            }
//            messageException.getErrorMessages().addMessage(
//               PERIOD_TYPE_OBJ, 
//               "You have to set valid period dynamic start attribute for " 
//               + strPeriodName + " type."
//            );
//         }
//      }
//   }
}





Get the days difference

   
/*
 * Copyright Javelin Software, All rights reserved.
 */

import java.util.*;
import java.text.*;
/**
 * The DateUtil is used as a Utility Class for Dates.
 * 
 * @author Robin Sharp
 */
public class DateUtil 
{
    public final static long SECOND_MILLIS = 1000;
    public final static long MINUTE_MILLIS = SECOND_MILLIS*60;
    public final static long HOUR_MILLIS = MINUTE_MILLIS*60;
    public final static long DAY_MILLIS = HOUR_MILLIS*24;
    public final static long YEAR_MILLIS = DAY_MILLIS*365;
    public static DateFormat OUT_DATE_FORMAT = new SimpleDateFormat("dd/MM/yyyy");
    public static DateFormat OUT_TIME_FORMAT = new SimpleDateFormat("H:mm:ss");
    public static DateFormat OUT_DATETIME_FORMAT = new SimpleDateFormat("d/M/yyyy H:mm:ss");
    public static DateFormat OUT_TIMESTAMP_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss.SSS");
    
    public static DateFormat IN_DATE_FORMAT = new SimpleDateFormat("d/M/yy");
    public static DateFormat IN_TIME_FORMAT = new SimpleDateFormat("H:mm:ss");
    public static DateFormat IN_DATETIME_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss");
    public static DateFormat IN_TIMESTAMP_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss.SSS");
    
    public static DateFormat DATE_TIME_FORMAT= new SimpleDateFormat( "yyyyMMddkkmmss" );  
    public static Calendar calendar = new GregorianCalendar();
    static
    {
        IN_DATE_FORMAT.setLenient(false);
        IN_TIME_FORMAT.setLenient(false);
        IN_DATETIME_FORMAT.setLenient(false);
    }
    /**
     * Create a new DateTime. To the last second. This will not create any 
     * extra-millis-seconds, which may cause bugs when writing to stores such as
     * databases that round milli-seconds up and down. 
     */
    public static java.util.Date newDateTime()
    {
        return new java.util.Date( (System.currentTimeMillis()/SECOND_MILLIS)*SECOND_MILLIS);
    }
    /**
     * Create a new Date. To the last day.
     */
    public static java.sql.Date newDate()
    {
        return new java.sql.Date( (System.currentTimeMillis()/DAY_MILLIS)*DAY_MILLIS);
    }
    
    /**
     * Create a new Time, with no date component. 
     */
    public static java.sql.Time newTime()
    {
        return new java.sql.Time( System.currentTimeMillis()%DAY_MILLIS);
    }
    
    /**
     * Create a new Timestamp. 
     */
    public static java.sql.Timestamp newTimestamp()
    {
        return new java.sql.Timestamp( System.currentTimeMillis() );
    }
    
    /**
     * Get the seconds difference
     */
    public static int secondsDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/SECOND_MILLIS) - (earlierDate.getTime()/SECOND_MILLIS));
    }
    /**
     * Get the minutes difference
     */
    public static int minutesDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/MINUTE_MILLIS) - (earlierDate.getTime()/MINUTE_MILLIS));
    }
    
    /**
     * Get the hours difference
     */
    public static int hoursDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/HOUR_MILLIS) - (earlierDate.getTime()/HOUR_MILLIS));
    }
    
    /**
     * Get the days difference
     */
    public static int daysDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/DAY_MILLIS) - (earlierDate.getTime()/DAY_MILLIS));
    }
    
   /**
    * Roll the java.util.Time forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.sql.Time rollTime( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.sql.Time(gc.getTime().getTime());
    }
    
   /**
    * Roll the java.util.Date forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.util.Date rollDateTime( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.util.Date(gc.getTime().getTime());
    }
    
   /**
    * Roll the java.sql.Date forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.sql.Date rollDate( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.sql.Date(gc.getTime().getTime());
    }
    
   /**
    * Roll the years forward or backward.
    * @param startDate - The start date
    * @param years - Negative to rollbackwards.
    */
    public static java.sql.Date rollYears( java.util.Date startDate, int years )
    {
        return rollDate( startDate, Calendar.YEAR, years );
    }
   /**
    * Roll the days forward or backward.
    * @param startDate - The start date
    * @param months - Negative to rollbackwards.
    */
    public static java.sql.Date rollMonths( java.util.Date startDate, int months )
    {
        return rollDate( startDate, Calendar.MONTH, months );
    }
   /**
    * Roll the days forward or backward.
    * @param startDate - The start date
    * @param days - Negative to rollbackwards.
    */
    public static java.sql.Date rollDays( java.util.Date startDate, int days )
    {
        return rollDate( startDate, Calendar.DATE, days );
    }
    
     /**
      * Checks the day, month and year are equal.
      */
     public static boolean dateEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;
        
        return d1.getDate() == d2.getDate() &&
               d1.getMonth() == d2.getMonth() &&
               d1.getYear() == d2.getYear();
     }
     
     /**
      * Checks the hour, minute and second are equal.
      */
     public static boolean timeEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;
        
        return d1.getHours() == d2.getHours() &&
               d1.getMinutes() == d2.getMinutes() &&
               d1.getSeconds() == d2.getSeconds();
     }

    /**
      * Checks the second, hour, month, day, month and year are equal.
      */
     public static boolean dateTimeEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;               
        
        return d1.getDate() == d2.getDate() &&
               d1.getMonth() == d2.getMonth() &&
               d1.getYear() == d2.getYear() &&
               d1.getHours() == d2.getHours() &&
               d1.getMinutes() == d2.getMinutes() &&
               d1.getSeconds() == d2.getSeconds();
     }
     
     /**
     * Convert an Object of type Classs to an Object.
     */
    public static Object toObject( Class clazz, Object value ) throws ParseException
    {
        if( value == null ) return null;
        if( clazz == null ) return value;
        
        if( java.sql.Date.class.isAssignableFrom( clazz ) ) return toDate( value );
        if( java.sql.Time.class.isAssignableFrom( clazz ) ) return toTime( value );
        if( java.sql.Timestamp.class.isAssignableFrom( clazz ) ) return toTimestamp( value );
        if( java.util.Date.class.isAssignableFrom( clazz ) ) return toDateTime( value );
        
        return value;
    }
    
    /**
     * Convert an Object to a DateTime, without an Exception
     */
    public static java.util.Date getDateTime( Object value )
    {
        try
        {
            return toDateTime( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    
    /**
     * Convert an Object to a DateTime.
     */
    public static java.util.Date toDateTime( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.util.Date ) return (java.util.Date)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return IN_DATETIME_FORMAT.parse( (String)value );
        }
                
        return IN_DATETIME_FORMAT.parse( value.toString() );
    }
    
    /**
     * Convert an Object to a Date, without an Exception
     */
    public static java.sql.Date getDate( Object value )
    {
        try
        {
            return toDate( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    /**
     * Convert an Object to a Date.
     */
    public static java.sql.Date toDate( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Date ) return (java.sql.Date)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Date( IN_DATE_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Date( IN_DATE_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Convert an Object to a Time, without an Exception
     */
    public static java.sql.Time getTime( Object value )
    {
        try
        {
            return toTime( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    
    /**
     * Convert an Object to a Time.
     */
    public static java.sql.Time toTime( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Time ) return (java.sql.Time)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Time( IN_TIME_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Time( IN_TIME_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Convert an Object to a Timestamp, without an Exception
     */
    public static java.sql.Timestamp getTimestamp( Object value )
    {
        try
        {
            return toTimestamp( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    /**
     * Convert an Object to a Timestamp.
     */
    public static java.sql.Timestamp toTimestamp( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Timestamp ) return (java.sql.Timestamp)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Timestamp( IN_TIMESTAMP_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Timestamp( IN_TIMESTAMP_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Tells you if the date part of a datetime is in a certain time range.
     */
    public static boolean isTimeInRange( java.sql.Time start, java.sql.Time end, java.util.Date d )
    {
        d=new java.sql.Time(d.getHours(),d.getMinutes(),d.getSeconds());
        
        if (start==null || end==null)
        {
            return false;
        }
        
        if (start.before(end)&&(!(d.after(start)&&d.before(end))))
        {
            return false;
        }
        
        if (end.before(start)&&(!(d.after(end)||d.before(start))))
        {
            return false;
        }   
        return true;
    }
    public static  int getYear( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.YEAR );
    }
    public static int getMonth( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MONTH );
    }
    public static int getDate( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.DATE );
    }
    public static int getHour( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.HOUR );
    }
    public static int getMinute( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MINUTE );
    }
    public static int getSeconds( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.SECOND );
    }
    public static int getMillisecond( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MILLISECOND );
    }
    
    /**
     * Convert an Object to a String using Dates
     */
    public static String toString( Object date )
    {
        if( date == null ) return null;
        
        if( java.sql.Timestamp.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_TIMESTAMP_FORMAT.format( date );
        }
        if( java.sql.Time.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_TIME_FORMAT.format( date );
        }
        if( java.sql.Date.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_DATE_FORMAT.format( date );
        }
        if( java.util.Date.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_DATETIME_FORMAT.format( date );
        }
        
        throw new IllegalArgumentException( "Unsupported type " + date.getClass() );
    }
}





Get the days passed from the specified date up to the date provided in the constructor

   
/*
 * Funambol is a mobile platform developed by Funambol, Inc. 
 * Copyright (C) 2003 - 2007 Funambol, Inc.
 * 
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Affero General Public License version 3 as published by
 * the Free Software Foundation with the addition of the following permission 
 * added to Section 15 as permitted in Section 7(a): FOR ANY PART OF THE COVERED
 * WORK IN WHICH THE COPYRIGHT IS OWNED BY FUNAMBOL, FUNAMBOL DISCLAIMS THE 
 * WARRANTY OF NON INFRINGEMENT  OF THIRD PARTY RIGHTS.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU Affero General Public License 
 * along with this program; if not, see http://www.gnu.org/licenses or write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301 USA.
 * 
 * You can contact Funambol, Inc. headquarters at 643 Bair Island Road, Suite 
 * 305, Redwood City, CA 94063, USA, or at email address info@funambol.ru.
 * 
 * The interactive user interfaces in modified source and object code versions
 * of this program must display Appropriate Legal Notices, as required under
 * Section 5 of the GNU Affero General Public License version 3.
 * 
 * In accordance with Section 7(b) of the GNU Affero General Public License
 * version 3, these Appropriate Legal Notices must retain the display of the
 * "Powered by Funambol" logo. If the display of the logo is not reasonably 
 * feasible for technical reasons, the Appropriate Legal Notices must display
 * the words "Powered by Funambol".
 */

import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;

/**
 * Utility class for date manipulation.
 * This class gives a simple interface for common Date, Calendar and Timezone
 * operations.
 * It is possible to apply subsequent transformations to an initial date, and
 * retrieve the changed Date object at any point.
 *
 */
public class DateUtil {
    
    //-------------------------------------------------------------- Attributes
    private Calendar cal;
    
    //------------------------------------------------------------ Constructors
    
    /** Inizialize a new instance with the current date */
    public DateUtil() {
        this(new Date());
    }
    
    /** Inizialize a new instance with the given date */
    public DateUtil(Date d) {
        cal = Calendar.getInstance();
        cal.setTime(d);
    }
    
    //---------------------------------------------------------- Public methods
    
    /** Set a new time */
    public void setTime(Date d) {
        cal.setTime(d);
    }
    
    /** Get the current time */
    public Date getTime() {
        return cal.getTime();
    }
    
    /** Get the current TimeZone */
    public String getTZ() {
        return cal.getTimeZone().getID();
    }
    
    /**
     * Convert the time to the midnight of the currently set date.
     * The internal date is changed after this call.
     *
     * @return a reference to this DateUtil, for concatenation.
     */
    public DateUtil toMidnight() {
        
        cal.set(Calendar.HOUR_OF_DAY, 0);
        cal.set(Calendar.MINUTE, 0);
        cal.set(Calendar.SECOND, 0);
        cal.set(Calendar.MILLISECOND,0);
        
        return this;
    }
    
    /**
     * Make the date go back of the specified amount of days
     * The internal date is changed after this call.
     *
     * @return a reference to this DateUtil, for concatenation.
     */
    public DateUtil removeDays(int days) {
        
        Date d = cal.getTime();
        long time = d.getTime();
        time -= days * 24 * 3600 * 1000;
        d.setTime(time);
        cal.setTime(d);
        
        return this;
    }
    
    /**
     * Make the date go forward of the specified amount of minutes
     * The internal date is changed after this call.
     *
     * @return a reference to this DateUtil, for concatenation.
     */
    public DateUtil addMinutes(int minutes) {
        Date d = cal.getTime();
        long time = d.getTime();
        time += minutes * 60 * 1000;
        d.setTime(time);
        cal.setTime(d);
        
        return this;
    }
    
    /**
     * Convert the date to GMT. The internal date is changed
     *
     * @return a reference to this DateUtil, for concatenation.
     */
    public DateUtil toGMT() {
        return toTZ("GMT");
    }
    
    /**
     * Convert the date to the given timezone. The internal date is changed.
     *
     * @param tz The name of the timezone to set
     *
     * @return a reference to this DateUtil, for concatenation.
     */
    public DateUtil toTZ(String tz) {
        cal.setTimeZone(TimeZone.getTimeZone(tz));
        
        return this;
    }
    
    /**
     * Get the days passed from the specified date up to the date provided 
     * in the constructor
     *
     * @param date The starting date
     *
     * @return number of days within date used in constructor and the provided
     * date
     */
    public int getDaysSince(Date date) {
        long millisecs = date.getTime();
        Date d = cal.getTime();
        long time = d.getTime();
        long daysMillisecs = time - millisecs;
        int days = (int)((((daysMillisecs / 1000)/60)/60)/24);
        return days;
    }
    
    /**
     * Utility method wrapping Calendar.after method
     * Compares the date field parameter with the date provided with the constructor
     * answering the question: date from constructor is after the given param date ?
     *
     * @param date The date to be used for comparison
     *
     * @return true if date from constructor is after given param date
     */
    public boolean isAfter(Date date) {
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date);
        return cal.after(cal2);
    }
}





Get the hours difference

   
/*
 * Copyright Javelin Software, All rights reserved.
 */

import java.util.*;
import java.text.*;
/**
 * The DateUtil is used as a Utility Class for Dates.
 * 
 * @author Robin Sharp
 */
public class DateUtil 
{
    public final static long SECOND_MILLIS = 1000;
    public final static long MINUTE_MILLIS = SECOND_MILLIS*60;
    public final static long HOUR_MILLIS = MINUTE_MILLIS*60;
    public final static long DAY_MILLIS = HOUR_MILLIS*24;
    public final static long YEAR_MILLIS = DAY_MILLIS*365;
    public static DateFormat OUT_DATE_FORMAT = new SimpleDateFormat("dd/MM/yyyy");
    public static DateFormat OUT_TIME_FORMAT = new SimpleDateFormat("H:mm:ss");
    public static DateFormat OUT_DATETIME_FORMAT = new SimpleDateFormat("d/M/yyyy H:mm:ss");
    public static DateFormat OUT_TIMESTAMP_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss.SSS");
    
    public static DateFormat IN_DATE_FORMAT = new SimpleDateFormat("d/M/yy");
    public static DateFormat IN_TIME_FORMAT = new SimpleDateFormat("H:mm:ss");
    public static DateFormat IN_DATETIME_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss");
    public static DateFormat IN_TIMESTAMP_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss.SSS");
    
    public static DateFormat DATE_TIME_FORMAT= new SimpleDateFormat( "yyyyMMddkkmmss" );  
    public static Calendar calendar = new GregorianCalendar();
    static
    {
        IN_DATE_FORMAT.setLenient(false);
        IN_TIME_FORMAT.setLenient(false);
        IN_DATETIME_FORMAT.setLenient(false);
    }
    /**
     * Create a new DateTime. To the last second. This will not create any 
     * extra-millis-seconds, which may cause bugs when writing to stores such as
     * databases that round milli-seconds up and down. 
     */
    public static java.util.Date newDateTime()
    {
        return new java.util.Date( (System.currentTimeMillis()/SECOND_MILLIS)*SECOND_MILLIS);
    }
    /**
     * Create a new Date. To the last day.
     */
    public static java.sql.Date newDate()
    {
        return new java.sql.Date( (System.currentTimeMillis()/DAY_MILLIS)*DAY_MILLIS);
    }
    
    /**
     * Create a new Time, with no date component. 
     */
    public static java.sql.Time newTime()
    {
        return new java.sql.Time( System.currentTimeMillis()%DAY_MILLIS);
    }
    
    /**
     * Create a new Timestamp. 
     */
    public static java.sql.Timestamp newTimestamp()
    {
        return new java.sql.Timestamp( System.currentTimeMillis() );
    }
    
    /**
     * Get the seconds difference
     */
    public static int secondsDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/SECOND_MILLIS) - (earlierDate.getTime()/SECOND_MILLIS));
    }
    /**
     * Get the minutes difference
     */
    public static int minutesDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/MINUTE_MILLIS) - (earlierDate.getTime()/MINUTE_MILLIS));
    }
    
    /**
     * Get the hours difference
     */
    public static int hoursDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/HOUR_MILLIS) - (earlierDate.getTime()/HOUR_MILLIS));
    }
    
    /**
     * Get the days difference
     */
    public static int daysDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/DAY_MILLIS) - (earlierDate.getTime()/DAY_MILLIS));
    }
    
   /**
    * Roll the java.util.Time forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.sql.Time rollTime( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.sql.Time(gc.getTime().getTime());
    }
    
   /**
    * Roll the java.util.Date forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.util.Date rollDateTime( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.util.Date(gc.getTime().getTime());
    }
    
   /**
    * Roll the java.sql.Date forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.sql.Date rollDate( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.sql.Date(gc.getTime().getTime());
    }
    
   /**
    * Roll the years forward or backward.
    * @param startDate - The start date
    * @param years - Negative to rollbackwards.
    */
    public static java.sql.Date rollYears( java.util.Date startDate, int years )
    {
        return rollDate( startDate, Calendar.YEAR, years );
    }
   /**
    * Roll the days forward or backward.
    * @param startDate - The start date
    * @param months - Negative to rollbackwards.
    */
    public static java.sql.Date rollMonths( java.util.Date startDate, int months )
    {
        return rollDate( startDate, Calendar.MONTH, months );
    }
   /**
    * Roll the days forward or backward.
    * @param startDate - The start date
    * @param days - Negative to rollbackwards.
    */
    public static java.sql.Date rollDays( java.util.Date startDate, int days )
    {
        return rollDate( startDate, Calendar.DATE, days );
    }
    
     /**
      * Checks the day, month and year are equal.
      */
     public static boolean dateEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;
        
        return d1.getDate() == d2.getDate() &&
               d1.getMonth() == d2.getMonth() &&
               d1.getYear() == d2.getYear();
     }
     
     /**
      * Checks the hour, minute and second are equal.
      */
     public static boolean timeEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;
        
        return d1.getHours() == d2.getHours() &&
               d1.getMinutes() == d2.getMinutes() &&
               d1.getSeconds() == d2.getSeconds();
     }

    /**
      * Checks the second, hour, month, day, month and year are equal.
      */
     public static boolean dateTimeEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;               
        
        return d1.getDate() == d2.getDate() &&
               d1.getMonth() == d2.getMonth() &&
               d1.getYear() == d2.getYear() &&
               d1.getHours() == d2.getHours() &&
               d1.getMinutes() == d2.getMinutes() &&
               d1.getSeconds() == d2.getSeconds();
     }
     
     /**
     * Convert an Object of type Classs to an Object.
     */
    public static Object toObject( Class clazz, Object value ) throws ParseException
    {
        if( value == null ) return null;
        if( clazz == null ) return value;
        
        if( java.sql.Date.class.isAssignableFrom( clazz ) ) return toDate( value );
        if( java.sql.Time.class.isAssignableFrom( clazz ) ) return toTime( value );
        if( java.sql.Timestamp.class.isAssignableFrom( clazz ) ) return toTimestamp( value );
        if( java.util.Date.class.isAssignableFrom( clazz ) ) return toDateTime( value );
        
        return value;
    }
    
    /**
     * Convert an Object to a DateTime, without an Exception
     */
    public static java.util.Date getDateTime( Object value )
    {
        try
        {
            return toDateTime( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    
    /**
     * Convert an Object to a DateTime.
     */
    public static java.util.Date toDateTime( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.util.Date ) return (java.util.Date)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return IN_DATETIME_FORMAT.parse( (String)value );
        }
                
        return IN_DATETIME_FORMAT.parse( value.toString() );
    }
    
    /**
     * Convert an Object to a Date, without an Exception
     */
    public static java.sql.Date getDate( Object value )
    {
        try
        {
            return toDate( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    /**
     * Convert an Object to a Date.
     */
    public static java.sql.Date toDate( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Date ) return (java.sql.Date)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Date( IN_DATE_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Date( IN_DATE_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Convert an Object to a Time, without an Exception
     */
    public static java.sql.Time getTime( Object value )
    {
        try
        {
            return toTime( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    
    /**
     * Convert an Object to a Time.
     */
    public static java.sql.Time toTime( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Time ) return (java.sql.Time)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Time( IN_TIME_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Time( IN_TIME_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Convert an Object to a Timestamp, without an Exception
     */
    public static java.sql.Timestamp getTimestamp( Object value )
    {
        try
        {
            return toTimestamp( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    /**
     * Convert an Object to a Timestamp.
     */
    public static java.sql.Timestamp toTimestamp( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Timestamp ) return (java.sql.Timestamp)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Timestamp( IN_TIMESTAMP_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Timestamp( IN_TIMESTAMP_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Tells you if the date part of a datetime is in a certain time range.
     */
    public static boolean isTimeInRange( java.sql.Time start, java.sql.Time end, java.util.Date d )
    {
        d=new java.sql.Time(d.getHours(),d.getMinutes(),d.getSeconds());
        
        if (start==null || end==null)
        {
            return false;
        }
        
        if (start.before(end)&&(!(d.after(start)&&d.before(end))))
        {
            return false;
        }
        
        if (end.before(start)&&(!(d.after(end)||d.before(start))))
        {
            return false;
        }   
        return true;
    }
    public static  int getYear( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.YEAR );
    }
    public static int getMonth( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MONTH );
    }
    public static int getDate( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.DATE );
    }
    public static int getHour( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.HOUR );
    }
    public static int getMinute( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MINUTE );
    }
    public static int getSeconds( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.SECOND );
    }
    public static int getMillisecond( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MILLISECOND );
    }
    
    /**
     * Convert an Object to a String using Dates
     */
    public static String toString( Object date )
    {
        if( date == null ) return null;
        
        if( java.sql.Timestamp.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_TIMESTAMP_FORMAT.format( date );
        }
        if( java.sql.Time.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_TIME_FORMAT.format( date );
        }
        if( java.sql.Date.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_DATE_FORMAT.format( date );
        }
        if( java.util.Date.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_DATETIME_FORMAT.format( date );
        }
        
        throw new IllegalArgumentException( "Unsupported type " + date.getClass() );
    }
}





Get the minutes difference

   
/*
 * Copyright Javelin Software, All rights reserved.
 */

import java.util.*;
import java.text.*;
/**
 * The DateUtil is used as a Utility Class for Dates.
 * 
 * @author Robin Sharp
 */
public class DateUtil 
{
    public final static long SECOND_MILLIS = 1000;
    public final static long MINUTE_MILLIS = SECOND_MILLIS*60;
    public final static long HOUR_MILLIS = MINUTE_MILLIS*60;
    public final static long DAY_MILLIS = HOUR_MILLIS*24;
    public final static long YEAR_MILLIS = DAY_MILLIS*365;
    public static DateFormat OUT_DATE_FORMAT = new SimpleDateFormat("dd/MM/yyyy");
    public static DateFormat OUT_TIME_FORMAT = new SimpleDateFormat("H:mm:ss");
    public static DateFormat OUT_DATETIME_FORMAT = new SimpleDateFormat("d/M/yyyy H:mm:ss");
    public static DateFormat OUT_TIMESTAMP_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss.SSS");
    
    public static DateFormat IN_DATE_FORMAT = new SimpleDateFormat("d/M/yy");
    public static DateFormat IN_TIME_FORMAT = new SimpleDateFormat("H:mm:ss");
    public static DateFormat IN_DATETIME_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss");
    public static DateFormat IN_TIMESTAMP_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss.SSS");
    
    public static DateFormat DATE_TIME_FORMAT= new SimpleDateFormat( "yyyyMMddkkmmss" );  
    public static Calendar calendar = new GregorianCalendar();
    static
    {
        IN_DATE_FORMAT.setLenient(false);
        IN_TIME_FORMAT.setLenient(false);
        IN_DATETIME_FORMAT.setLenient(false);
    }
    /**
     * Create a new DateTime. To the last second. This will not create any 
     * extra-millis-seconds, which may cause bugs when writing to stores such as
     * databases that round milli-seconds up and down. 
     */
    public static java.util.Date newDateTime()
    {
        return new java.util.Date( (System.currentTimeMillis()/SECOND_MILLIS)*SECOND_MILLIS);
    }
    /**
     * Create a new Date. To the last day.
     */
    public static java.sql.Date newDate()
    {
        return new java.sql.Date( (System.currentTimeMillis()/DAY_MILLIS)*DAY_MILLIS);
    }
    
    /**
     * Create a new Time, with no date component. 
     */
    public static java.sql.Time newTime()
    {
        return new java.sql.Time( System.currentTimeMillis()%DAY_MILLIS);
    }
    
    /**
     * Create a new Timestamp. 
     */
    public static java.sql.Timestamp newTimestamp()
    {
        return new java.sql.Timestamp( System.currentTimeMillis() );
    }
    
    /**
     * Get the seconds difference
     */
    public static int secondsDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/SECOND_MILLIS) - (earlierDate.getTime()/SECOND_MILLIS));
    }
    /**
     * Get the minutes difference
     */
    public static int minutesDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/MINUTE_MILLIS) - (earlierDate.getTime()/MINUTE_MILLIS));
    }
    
    /**
     * Get the hours difference
     */
    public static int hoursDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/HOUR_MILLIS) - (earlierDate.getTime()/HOUR_MILLIS));
    }
    
    /**
     * Get the days difference
     */
    public static int daysDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/DAY_MILLIS) - (earlierDate.getTime()/DAY_MILLIS));
    }
    
   /**
    * Roll the java.util.Time forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.sql.Time rollTime( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.sql.Time(gc.getTime().getTime());
    }
    
   /**
    * Roll the java.util.Date forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.util.Date rollDateTime( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.util.Date(gc.getTime().getTime());
    }
    
   /**
    * Roll the java.sql.Date forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.sql.Date rollDate( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.sql.Date(gc.getTime().getTime());
    }
    
   /**
    * Roll the years forward or backward.
    * @param startDate - The start date
    * @param years - Negative to rollbackwards.
    */
    public static java.sql.Date rollYears( java.util.Date startDate, int years )
    {
        return rollDate( startDate, Calendar.YEAR, years );
    }
   /**
    * Roll the days forward or backward.
    * @param startDate - The start date
    * @param months - Negative to rollbackwards.
    */
    public static java.sql.Date rollMonths( java.util.Date startDate, int months )
    {
        return rollDate( startDate, Calendar.MONTH, months );
    }
   /**
    * Roll the days forward or backward.
    * @param startDate - The start date
    * @param days - Negative to rollbackwards.
    */
    public static java.sql.Date rollDays( java.util.Date startDate, int days )
    {
        return rollDate( startDate, Calendar.DATE, days );
    }
    
     /**
      * Checks the day, month and year are equal.
      */
     public static boolean dateEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;
        
        return d1.getDate() == d2.getDate() &&
               d1.getMonth() == d2.getMonth() &&
               d1.getYear() == d2.getYear();
     }
     
     /**
      * Checks the hour, minute and second are equal.
      */
     public static boolean timeEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;
        
        return d1.getHours() == d2.getHours() &&
               d1.getMinutes() == d2.getMinutes() &&
               d1.getSeconds() == d2.getSeconds();
     }

    /**
      * Checks the second, hour, month, day, month and year are equal.
      */
     public static boolean dateTimeEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;               
        
        return d1.getDate() == d2.getDate() &&
               d1.getMonth() == d2.getMonth() &&
               d1.getYear() == d2.getYear() &&
               d1.getHours() == d2.getHours() &&
               d1.getMinutes() == d2.getMinutes() &&
               d1.getSeconds() == d2.getSeconds();
     }
     
     /**
     * Convert an Object of type Classs to an Object.
     */
    public static Object toObject( Class clazz, Object value ) throws ParseException
    {
        if( value == null ) return null;
        if( clazz == null ) return value;
        
        if( java.sql.Date.class.isAssignableFrom( clazz ) ) return toDate( value );
        if( java.sql.Time.class.isAssignableFrom( clazz ) ) return toTime( value );
        if( java.sql.Timestamp.class.isAssignableFrom( clazz ) ) return toTimestamp( value );
        if( java.util.Date.class.isAssignableFrom( clazz ) ) return toDateTime( value );
        
        return value;
    }
    
    /**
     * Convert an Object to a DateTime, without an Exception
     */
    public static java.util.Date getDateTime( Object value )
    {
        try
        {
            return toDateTime( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    
    /**
     * Convert an Object to a DateTime.
     */
    public static java.util.Date toDateTime( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.util.Date ) return (java.util.Date)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return IN_DATETIME_FORMAT.parse( (String)value );
        }
                
        return IN_DATETIME_FORMAT.parse( value.toString() );
    }
    
    /**
     * Convert an Object to a Date, without an Exception
     */
    public static java.sql.Date getDate( Object value )
    {
        try
        {
            return toDate( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    /**
     * Convert an Object to a Date.
     */
    public static java.sql.Date toDate( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Date ) return (java.sql.Date)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Date( IN_DATE_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Date( IN_DATE_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Convert an Object to a Time, without an Exception
     */
    public static java.sql.Time getTime( Object value )
    {
        try
        {
            return toTime( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    
    /**
     * Convert an Object to a Time.
     */
    public static java.sql.Time toTime( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Time ) return (java.sql.Time)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Time( IN_TIME_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Time( IN_TIME_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Convert an Object to a Timestamp, without an Exception
     */
    public static java.sql.Timestamp getTimestamp( Object value )
    {
        try
        {
            return toTimestamp( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    /**
     * Convert an Object to a Timestamp.
     */
    public static java.sql.Timestamp toTimestamp( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Timestamp ) return (java.sql.Timestamp)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Timestamp( IN_TIMESTAMP_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Timestamp( IN_TIMESTAMP_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Tells you if the date part of a datetime is in a certain time range.
     */
    public static boolean isTimeInRange( java.sql.Time start, java.sql.Time end, java.util.Date d )
    {
        d=new java.sql.Time(d.getHours(),d.getMinutes(),d.getSeconds());
        
        if (start==null || end==null)
        {
            return false;
        }
        
        if (start.before(end)&&(!(d.after(start)&&d.before(end))))
        {
            return false;
        }
        
        if (end.before(start)&&(!(d.after(end)||d.before(start))))
        {
            return false;
        }   
        return true;
    }
    public static  int getYear( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.YEAR );
    }
    public static int getMonth( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MONTH );
    }
    public static int getDate( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.DATE );
    }
    public static int getHour( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.HOUR );
    }
    public static int getMinute( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MINUTE );
    }
    public static int getSeconds( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.SECOND );
    }
    public static int getMillisecond( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MILLISECOND );
    }
    
    /**
     * Convert an Object to a String using Dates
     */
    public static String toString( Object date )
    {
        if( date == null ) return null;
        
        if( java.sql.Timestamp.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_TIMESTAMP_FORMAT.format( date );
        }
        if( java.sql.Time.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_TIME_FORMAT.format( date );
        }
        if( java.sql.Date.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_DATE_FORMAT.format( date );
        }
        if( java.util.Date.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_DATETIME_FORMAT.format( date );
        }
        
        throw new IllegalArgumentException( "Unsupported type " + date.getClass() );
    }
}





Get the seconds difference

   
/*
 * Copyright Javelin Software, All rights reserved.
 */

import java.util.*;
import java.text.*;
/**
 * The DateUtil is used as a Utility Class for Dates.
 * 
 * @author Robin Sharp
 */
public class DateUtil 
{
    public final static long SECOND_MILLIS = 1000;
    public final static long MINUTE_MILLIS = SECOND_MILLIS*60;
    public final static long HOUR_MILLIS = MINUTE_MILLIS*60;
    public final static long DAY_MILLIS = HOUR_MILLIS*24;
    public final static long YEAR_MILLIS = DAY_MILLIS*365;
    public static DateFormat OUT_DATE_FORMAT = new SimpleDateFormat("dd/MM/yyyy");
    public static DateFormat OUT_TIME_FORMAT = new SimpleDateFormat("H:mm:ss");
    public static DateFormat OUT_DATETIME_FORMAT = new SimpleDateFormat("d/M/yyyy H:mm:ss");
    public static DateFormat OUT_TIMESTAMP_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss.SSS");
    
    public static DateFormat IN_DATE_FORMAT = new SimpleDateFormat("d/M/yy");
    public static DateFormat IN_TIME_FORMAT = new SimpleDateFormat("H:mm:ss");
    public static DateFormat IN_DATETIME_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss");
    public static DateFormat IN_TIMESTAMP_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss.SSS");
    
    public static DateFormat DATE_TIME_FORMAT= new SimpleDateFormat( "yyyyMMddkkmmss" );  
    public static Calendar calendar = new GregorianCalendar();
    static
    {
        IN_DATE_FORMAT.setLenient(false);
        IN_TIME_FORMAT.setLenient(false);
        IN_DATETIME_FORMAT.setLenient(false);
    }
    /**
     * Create a new DateTime. To the last second. This will not create any 
     * extra-millis-seconds, which may cause bugs when writing to stores such as
     * databases that round milli-seconds up and down. 
     */
    public static java.util.Date newDateTime()
    {
        return new java.util.Date( (System.currentTimeMillis()/SECOND_MILLIS)*SECOND_MILLIS);
    }
    /**
     * Create a new Date. To the last day.
     */
    public static java.sql.Date newDate()
    {
        return new java.sql.Date( (System.currentTimeMillis()/DAY_MILLIS)*DAY_MILLIS);
    }
    
    /**
     * Create a new Time, with no date component. 
     */
    public static java.sql.Time newTime()
    {
        return new java.sql.Time( System.currentTimeMillis()%DAY_MILLIS);
    }
    
    /**
     * Create a new Timestamp. 
     */
    public static java.sql.Timestamp newTimestamp()
    {
        return new java.sql.Timestamp( System.currentTimeMillis() );
    }
    
    /**
     * Get the seconds difference
     */
    public static int secondsDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/SECOND_MILLIS) - (earlierDate.getTime()/SECOND_MILLIS));
    }
    /**
     * Get the minutes difference
     */
    public static int minutesDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/MINUTE_MILLIS) - (earlierDate.getTime()/MINUTE_MILLIS));
    }
    
    /**
     * Get the hours difference
     */
    public static int hoursDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/HOUR_MILLIS) - (earlierDate.getTime()/HOUR_MILLIS));
    }
    
    /**
     * Get the days difference
     */
    public static int daysDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/DAY_MILLIS) - (earlierDate.getTime()/DAY_MILLIS));
    }
    
   /**
    * Roll the java.util.Time forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.sql.Time rollTime( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.sql.Time(gc.getTime().getTime());
    }
    
   /**
    * Roll the java.util.Date forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.util.Date rollDateTime( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.util.Date(gc.getTime().getTime());
    }
    
   /**
    * Roll the java.sql.Date forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.sql.Date rollDate( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.sql.Date(gc.getTime().getTime());
    }
    
   /**
    * Roll the years forward or backward.
    * @param startDate - The start date
    * @param years - Negative to rollbackwards.
    */
    public static java.sql.Date rollYears( java.util.Date startDate, int years )
    {
        return rollDate( startDate, Calendar.YEAR, years );
    }
   /**
    * Roll the days forward or backward.
    * @param startDate - The start date
    * @param months - Negative to rollbackwards.
    */
    public static java.sql.Date rollMonths( java.util.Date startDate, int months )
    {
        return rollDate( startDate, Calendar.MONTH, months );
    }
   /**
    * Roll the days forward or backward.
    * @param startDate - The start date
    * @param days - Negative to rollbackwards.
    */
    public static java.sql.Date rollDays( java.util.Date startDate, int days )
    {
        return rollDate( startDate, Calendar.DATE, days );
    }
    
     /**
      * Checks the day, month and year are equal.
      */
     public static boolean dateEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;
        
        return d1.getDate() == d2.getDate() &&
               d1.getMonth() == d2.getMonth() &&
               d1.getYear() == d2.getYear();
     }
     
     /**
      * Checks the hour, minute and second are equal.
      */
     public static boolean timeEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;
        
        return d1.getHours() == d2.getHours() &&
               d1.getMinutes() == d2.getMinutes() &&
               d1.getSeconds() == d2.getSeconds();
     }

    /**
      * Checks the second, hour, month, day, month and year are equal.
      */
     public static boolean dateTimeEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;               
        
        return d1.getDate() == d2.getDate() &&
               d1.getMonth() == d2.getMonth() &&
               d1.getYear() == d2.getYear() &&
               d1.getHours() == d2.getHours() &&
               d1.getMinutes() == d2.getMinutes() &&
               d1.getSeconds() == d2.getSeconds();
     }
     
     /**
     * Convert an Object of type Classs to an Object.
     */
    public static Object toObject( Class clazz, Object value ) throws ParseException
    {
        if( value == null ) return null;
        if( clazz == null ) return value;
        
        if( java.sql.Date.class.isAssignableFrom( clazz ) ) return toDate( value );
        if( java.sql.Time.class.isAssignableFrom( clazz ) ) return toTime( value );
        if( java.sql.Timestamp.class.isAssignableFrom( clazz ) ) return toTimestamp( value );
        if( java.util.Date.class.isAssignableFrom( clazz ) ) return toDateTime( value );
        
        return value;
    }
    
    /**
     * Convert an Object to a DateTime, without an Exception
     */
    public static java.util.Date getDateTime( Object value )
    {
        try
        {
            return toDateTime( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    
    /**
     * Convert an Object to a DateTime.
     */
    public static java.util.Date toDateTime( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.util.Date ) return (java.util.Date)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return IN_DATETIME_FORMAT.parse( (String)value );
        }
                
        return IN_DATETIME_FORMAT.parse( value.toString() );
    }
    
    /**
     * Convert an Object to a Date, without an Exception
     */
    public static java.sql.Date getDate( Object value )
    {
        try
        {
            return toDate( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    /**
     * Convert an Object to a Date.
     */
    public static java.sql.Date toDate( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Date ) return (java.sql.Date)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Date( IN_DATE_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Date( IN_DATE_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Convert an Object to a Time, without an Exception
     */
    public static java.sql.Time getTime( Object value )
    {
        try
        {
            return toTime( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    
    /**
     * Convert an Object to a Time.
     */
    public static java.sql.Time toTime( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Time ) return (java.sql.Time)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Time( IN_TIME_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Time( IN_TIME_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Convert an Object to a Timestamp, without an Exception
     */
    public static java.sql.Timestamp getTimestamp( Object value )
    {
        try
        {
            return toTimestamp( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    /**
     * Convert an Object to a Timestamp.
     */
    public static java.sql.Timestamp toTimestamp( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Timestamp ) return (java.sql.Timestamp)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Timestamp( IN_TIMESTAMP_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Timestamp( IN_TIMESTAMP_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Tells you if the date part of a datetime is in a certain time range.
     */
    public static boolean isTimeInRange( java.sql.Time start, java.sql.Time end, java.util.Date d )
    {
        d=new java.sql.Time(d.getHours(),d.getMinutes(),d.getSeconds());
        
        if (start==null || end==null)
        {
            return false;
        }
        
        if (start.before(end)&&(!(d.after(start)&&d.before(end))))
        {
            return false;
        }
        
        if (end.before(start)&&(!(d.after(end)||d.before(start))))
        {
            return false;
        }   
        return true;
    }
    public static  int getYear( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.YEAR );
    }
    public static int getMonth( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MONTH );
    }
    public static int getDate( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.DATE );
    }
    public static int getHour( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.HOUR );
    }
    public static int getMinute( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MINUTE );
    }
    public static int getSeconds( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.SECOND );
    }
    public static int getMillisecond( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MILLISECOND );
    }
    
    /**
     * Convert an Object to a String using Dates
     */
    public static String toString( Object date )
    {
        if( date == null ) return null;
        
        if( java.sql.Timestamp.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_TIMESTAMP_FORMAT.format( date );
        }
        if( java.sql.Time.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_TIME_FORMAT.format( date );
        }
        if( java.sql.Date.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_DATE_FORMAT.format( date );
        }
        if( java.util.Date.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_DATETIME_FORMAT.format( date );
        }
        
        throw new IllegalArgumentException( "Unsupported type " + date.getClass() );
    }
}





Make the date go back of the specified amount of days

  
/*
 * Funambol is a mobile platform developed by Funambol, Inc. 
 * Copyright (C) 2003 - 2007 Funambol, Inc.
 * 
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Affero General Public License version 3 as published by
 * the Free Software Foundation with the addition of the following permission 
 * added to Section 15 as permitted in Section 7(a): FOR ANY PART OF THE COVERED
 * WORK IN WHICH THE COPYRIGHT IS OWNED BY FUNAMBOL, FUNAMBOL DISCLAIMS THE 
 * WARRANTY OF NON INFRINGEMENT  OF THIRD PARTY RIGHTS.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU Affero General Public License 
 * along with this program; if not, see http://www.gnu.org/licenses or write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301 USA.
 * 
 * You can contact Funambol, Inc. headquarters at 643 Bair Island Road, Suite 
 * 305, Redwood City, CA 94063, USA, or at email address info@funambol.ru.
 * 
 * The interactive user interfaces in modified source and object code versions
 * of this program must display Appropriate Legal Notices, as required under
 * Section 5 of the GNU Affero General Public License version 3.
 * 
 * In accordance with Section 7(b) of the GNU Affero General Public License
 * version 3, these Appropriate Legal Notices must retain the display of the
 * "Powered by Funambol" logo. If the display of the logo is not reasonably 
 * feasible for technical reasons, the Appropriate Legal Notices must display
 * the words "Powered by Funambol".
 */

import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;

/**
 * Utility class for date manipulation.
 * This class gives a simple interface for common Date, Calendar and Timezone
 * operations.
 * It is possible to apply subsequent transformations to an initial date, and
 * retrieve the changed Date object at any point.
 *
 */
public class DateUtil {
    
    //-------------------------------------------------------------- Attributes
    private Calendar cal;
    
    //------------------------------------------------------------ Constructors
    
    /** Inizialize a new instance with the current date */
    public DateUtil() {
        this(new Date());
    }
    
    /** Inizialize a new instance with the given date */
    public DateUtil(Date d) {
        cal = Calendar.getInstance();
        cal.setTime(d);
    }
    
    //---------------------------------------------------------- Public methods
    
    /** Set a new time */
    public void setTime(Date d) {
        cal.setTime(d);
    }
    
    /** Get the current time */
    public Date getTime() {
        return cal.getTime();
    }
    
    /** Get the current TimeZone */
    public String getTZ() {
        return cal.getTimeZone().getID();
    }
    
    /**
     * Convert the time to the midnight of the currently set date.
     * The internal date is changed after this call.
     *
     * @return a reference to this DateUtil, for concatenation.
     */
    public DateUtil toMidnight() {
        
        cal.set(Calendar.HOUR_OF_DAY, 0);
        cal.set(Calendar.MINUTE, 0);
        cal.set(Calendar.SECOND, 0);
        cal.set(Calendar.MILLISECOND,0);
        
        return this;
    }
    
    /**
     * Make the date go back of the specified amount of days
     * The internal date is changed after this call.
     *
     * @return a reference to this DateUtil, for concatenation.
     */
    public DateUtil removeDays(int days) {
        
        Date d = cal.getTime();
        long time = d.getTime();
        time -= days * 24 * 3600 * 1000;
        d.setTime(time);
        cal.setTime(d);
        
        return this;
    }
    
    /**
     * Make the date go forward of the specified amount of minutes
     * The internal date is changed after this call.
     *
     * @return a reference to this DateUtil, for concatenation.
     */
    public DateUtil addMinutes(int minutes) {
        Date d = cal.getTime();
        long time = d.getTime();
        time += minutes * 60 * 1000;
        d.setTime(time);
        cal.setTime(d);
        
        return this;
    }
    
    /**
     * Convert the date to GMT. The internal date is changed
     *
     * @return a reference to this DateUtil, for concatenation.
     */
    public DateUtil toGMT() {
        return toTZ("GMT");
    }
    
    /**
     * Convert the date to the given timezone. The internal date is changed.
     *
     * @param tz The name of the timezone to set
     *
     * @return a reference to this DateUtil, for concatenation.
     */
    public DateUtil toTZ(String tz) {
        cal.setTimeZone(TimeZone.getTimeZone(tz));
        
        return this;
    }
    
    /**
     * Get the days passed from the specified date up to the date provided 
     * in the constructor
     *
     * @param date The starting date
     *
     * @return number of days within date used in constructor and the provided
     * date
     */
    public int getDaysSince(Date date) {
        long millisecs = date.getTime();
        Date d = cal.getTime();
        long time = d.getTime();
        long daysMillisecs = time - millisecs;
        int days = (int)((((daysMillisecs / 1000)/60)/60)/24);
        return days;
    }
    
    /**
     * Utility method wrapping Calendar.after method
     * Compares the date field parameter with the date provided with the constructor
     * answering the question: date from constructor is after the given param date ?
     *
     * @param date The date to be used for comparison
     *
     * @return true if date from constructor is after given param date
     */
    public boolean isAfter(Date date) {
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date);
        return cal.after(cal2);
    }
}





Make the date go forward of the specified amount of minutes

  
/*
 * Funambol is a mobile platform developed by Funambol, Inc. 
 * Copyright (C) 2003 - 2007 Funambol, Inc.
 * 
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Affero General Public License version 3 as published by
 * the Free Software Foundation with the addition of the following permission 
 * added to Section 15 as permitted in Section 7(a): FOR ANY PART OF THE COVERED
 * WORK IN WHICH THE COPYRIGHT IS OWNED BY FUNAMBOL, FUNAMBOL DISCLAIMS THE 
 * WARRANTY OF NON INFRINGEMENT  OF THIRD PARTY RIGHTS.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU Affero General Public License 
 * along with this program; if not, see http://www.gnu.org/licenses or write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301 USA.
 * 
 * You can contact Funambol, Inc. headquarters at 643 Bair Island Road, Suite 
 * 305, Redwood City, CA 94063, USA, or at email address info@funambol.ru.
 * 
 * The interactive user interfaces in modified source and object code versions
 * of this program must display Appropriate Legal Notices, as required under
 * Section 5 of the GNU Affero General Public License version 3.
 * 
 * In accordance with Section 7(b) of the GNU Affero General Public License
 * version 3, these Appropriate Legal Notices must retain the display of the
 * "Powered by Funambol" logo. If the display of the logo is not reasonably 
 * feasible for technical reasons, the Appropriate Legal Notices must display
 * the words "Powered by Funambol".
 */

import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;

/**
 * Utility class for date manipulation.
 * This class gives a simple interface for common Date, Calendar and Timezone
 * operations.
 * It is possible to apply subsequent transformations to an initial date, and
 * retrieve the changed Date object at any point.
 *
 */
public class DateUtil {
    
    //-------------------------------------------------------------- Attributes
    private Calendar cal;
    
    //------------------------------------------------------------ Constructors
    
    /** Inizialize a new instance with the current date */
    public DateUtil() {
        this(new Date());
    }
    
    /** Inizialize a new instance with the given date */
    public DateUtil(Date d) {
        cal = Calendar.getInstance();
        cal.setTime(d);
    }
    
    //---------------------------------------------------------- Public methods
    
    /** Set a new time */
    public void setTime(Date d) {
        cal.setTime(d);
    }
    
    /** Get the current time */
    public Date getTime() {
        return cal.getTime();
    }
    
    /** Get the current TimeZone */
    public String getTZ() {
        return cal.getTimeZone().getID();
    }
    
    /**
     * Convert the time to the midnight of the currently set date.
     * The internal date is changed after this call.
     *
     * @return a reference to this DateUtil, for concatenation.
     */
    public DateUtil toMidnight() {
        
        cal.set(Calendar.HOUR_OF_DAY, 0);
        cal.set(Calendar.MINUTE, 0);
        cal.set(Calendar.SECOND, 0);
        cal.set(Calendar.MILLISECOND,0);
        
        return this;
    }
    
    /**
     * Make the date go back of the specified amount of days
     * The internal date is changed after this call.
     *
     * @return a reference to this DateUtil, for concatenation.
     */
    public DateUtil removeDays(int days) {
        
        Date d = cal.getTime();
        long time = d.getTime();
        time -= days * 24 * 3600 * 1000;
        d.setTime(time);
        cal.setTime(d);
        
        return this;
    }
    
    /**
     * Make the date go forward of the specified amount of minutes
     * The internal date is changed after this call.
     *
     * @return a reference to this DateUtil, for concatenation.
     */
    public DateUtil addMinutes(int minutes) {
        Date d = cal.getTime();
        long time = d.getTime();
        time += minutes * 60 * 1000;
        d.setTime(time);
        cal.setTime(d);
        
        return this;
    }
    
    /**
     * Convert the date to GMT. The internal date is changed
     *
     * @return a reference to this DateUtil, for concatenation.
     */
    public DateUtil toGMT() {
        return toTZ("GMT");
    }
    
    /**
     * Convert the date to the given timezone. The internal date is changed.
     *
     * @param tz The name of the timezone to set
     *
     * @return a reference to this DateUtil, for concatenation.
     */
    public DateUtil toTZ(String tz) {
        cal.setTimeZone(TimeZone.getTimeZone(tz));
        
        return this;
    }
    
    /**
     * Get the days passed from the specified date up to the date provided 
     * in the constructor
     *
     * @param date The starting date
     *
     * @return number of days within date used in constructor and the provided
     * date
     */
    public int getDaysSince(Date date) {
        long millisecs = date.getTime();
        Date d = cal.getTime();
        long time = d.getTime();
        long daysMillisecs = time - millisecs;
        int days = (int)((((daysMillisecs / 1000)/60)/60)/24);
        return days;
    }
    
    /**
     * Utility method wrapping Calendar.after method
     * Compares the date field parameter with the date provided with the constructor
     * answering the question: date from constructor is after the given param date ?
     *
     * @param date The date to be used for comparison
     *
     * @return true if date from constructor is after given param date
     */
    public boolean isAfter(Date date) {
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date);
        return cal.after(cal2);
    }
}





Returns a Date set just to Noon, to the closest possible millisecond of the day.

  
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  The ASF licenses this file to You
 * under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.  For additional information regarding
 * copyright in this work, please see the NOTICE file in the top level
 * directory of this distribution.
 */
import java.util.Calendar;
import java.util.Date;
public class Utils {
  /**
   * Returns a Date set just to Noon, to the closest possible millisecond
   * of the day. If a null day is passed in, a new Date is created.
   * nnoon (00m 12h 00s)
   */
  public static Date getNoonOfDay(Date day, Calendar cal) {
      if (day == null) day = new Date();
      cal.setTime(day);
      cal.set(Calendar.HOUR_OF_DAY, 12);
      cal.set(Calendar.MINUTE,      cal.getMinimum(Calendar.MINUTE));
      cal.set(Calendar.SECOND,      cal.getMinimum(Calendar.SECOND));
      cal.set(Calendar.MILLISECOND, cal.getMinimum(Calendar.MILLISECOND));
      return cal.getTime();
  }
}





Returns a Date set to the first possible millisecond of the day, just after midnight.

  
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  The ASF licenses this file to You
 * under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.  For additional information regarding
 * copyright in this work, please see the NOTICE file in the top level
 * directory of this distribution.
 */
import java.util.Calendar;
import java.util.Date;
public class Utils {
  /**
   * Returns a Date set to the first possible millisecond of the day, just
   * after midnight. If a null day is passed in, a new Date is created.
   * midnight (00m 00h 00s)
   */
  public static Date getStartOfDay(Date day) {
      return getStartOfDay(day, Calendar.getInstance());
  }
  
  
  /**
   * Returns a Date set to the first possible millisecond of the day, just
   * after midnight. If a null day is passed in, a new Date is created.
   * midnight (00m 00h 00s)
   */
  public static Date getStartOfDay(Date day, Calendar cal) {
      if (day == null) day = new Date();
      cal.setTime(day);
      cal.set(Calendar.HOUR_OF_DAY, cal.getMinimum(Calendar.HOUR_OF_DAY));
      cal.set(Calendar.MINUTE,      cal.getMinimum(Calendar.MINUTE));
      cal.set(Calendar.SECOND,      cal.getMinimum(Calendar.SECOND));
      cal.set(Calendar.MILLISECOND, cal.getMinimum(Calendar.MILLISECOND));
      return cal.getTime();
  }
}





Returns a Date set to the first possible millisecond of the month, just after midnight.

  
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  The ASF licenses this file to You
 * under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.  For additional information regarding
 * copyright in this work, please see the NOTICE file in the top level
 * directory of this distribution.
 */
import java.util.Calendar;
import java.util.Date;
public class Utils {
  /**
   * Returns a Date set to the first possible millisecond of the month, just
   * after midnight. If a null day is passed in, a new Date is created.
   * midnight (00m 00h 00s)
   */
  public static Date getStartOfMonth(Date day) {
      return getStartOfMonth(day, Calendar.getInstance());
  }
  
  
  public static Date getStartOfMonth(Date day, Calendar cal) {
      if (day == null) day = new Date();
      cal.setTime(day);
      
      // set time to start of day
      cal.set(Calendar.HOUR_OF_DAY, cal.getMinimum(Calendar.HOUR_OF_DAY));
      cal.set(Calendar.MINUTE,      cal.getMinimum(Calendar.MINUTE));
      cal.set(Calendar.SECOND,      cal.getMinimum(Calendar.SECOND));
      cal.set(Calendar.MILLISECOND, cal.getMinimum(Calendar.MILLISECOND));
      
      // set time to first day of month
      cal.set(Calendar.DAY_OF_MONTH, 1);
      
      return cal.getTime();
  }
}





Returns a Date set to the last possible millisecond of the day, just before midnight.

  
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  The ASF licenses this file to You
 * under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.  For additional information regarding
 * copyright in this work, please see the NOTICE file in the top level
 * directory of this distribution.
 */
import java.util.Calendar;
import java.util.Date;
public class Utils {
  /**
   * Returns a Date set to the last possible millisecond of the day, just
   * before midnight. If a null day is passed in, a new Date is created.
   * midnight (00m 00h 00s)
   */
  public static Date getEndOfDay(Date day) {
      return getEndOfDay(day,Calendar.getInstance());
  }
  
  
  public static Date getEndOfDay(Date day,Calendar cal) {
      if (day == null) day = new Date();
      cal.setTime(day);
      cal.set(Calendar.HOUR_OF_DAY, cal.getMaximum(Calendar.HOUR_OF_DAY));
      cal.set(Calendar.MINUTE,      cal.getMaximum(Calendar.MINUTE));
      cal.set(Calendar.SECOND,      cal.getMaximum(Calendar.SECOND));
      cal.set(Calendar.MILLISECOND, cal.getMaximum(Calendar.MILLISECOND));
      return cal.getTime();
  }

}





Returns a Date set to the last possible millisecond of the minute.

  
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  The ASF licenses this file to You
 * under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.  For additional information regarding
 * copyright in this work, please see the NOTICE file in the top level
 * directory of this distribution.
 */
import java.util.Calendar;
import java.util.Date;
public class Utils {
  /**
   * Returns a Date set to the last possible millisecond of the minute.
   * If a null day is passed in, a new Date is created.
   */
  public static Date getEndOfMinute(Date day) {
      return getEndOfMinute(day, Calendar.getInstance());
  }
  
  
  public static Date getEndOfMinute(Date day, Calendar cal) {
      if (day == null || cal == null) {
          return day;
      }
      
      cal.setTime(day);
      cal.set(Calendar.SECOND,      cal.getMaximum(Calendar.SECOND));
      cal.set(Calendar.MILLISECOND, cal.getMaximum(Calendar.MILLISECOND));
      return cal.getTime();
  }
}





Returns a Date set to the last possible millisecond of the month, just before midnight.

  
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  The ASF licenses this file to You
 * under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.  For additional information regarding
 * copyright in this work, please see the NOTICE file in the top level
 * directory of this distribution.
 */
import java.util.Calendar;
import java.util.Date;
public class Utils {
  /**
   * Returns a Date set to the last possible millisecond of the month, just
   * before midnight. If a null day is passed in, a new Date is created.
   * midnight (00m 00h 00s)
   */
  public static Date getEndOfMonth(Date day) {
      return getEndOfMonth(day, Calendar.getInstance());
  }
  
  
  public static Date getEndOfMonth(Date day,Calendar cal) {
      if (day == null) day = new Date();
      cal.setTime(day);
      
      // set time to end of day
      cal.set(Calendar.HOUR_OF_DAY, cal.getMaximum(Calendar.HOUR_OF_DAY));
      cal.set(Calendar.MINUTE,      cal.getMaximum(Calendar.MINUTE));
      cal.set(Calendar.SECOND,      cal.getMaximum(Calendar.SECOND));
      cal.set(Calendar.MILLISECOND, cal.getMaximum(Calendar.MILLISECOND));
      
      // set time to first day of month
      cal.set(Calendar.DAY_OF_MONTH, 1);
      
      // add one month
      cal.add(Calendar.MONTH, 1);
      
      // back up one day
      cal.add(Calendar.DAY_OF_MONTH, -1);
      
      return cal.getTime();
  }
}





Returns a java.sql.Timestamp equal to the current time

  
public class Utils {
  
  /**
   * Returns a java.sql.Timestamp equal to the current time
   **/
  public static java.sql.Timestamp now() {
      return new java.sql.Timestamp(new java.util.Date().getTime());
  }
}





Returns the maximum of two dates. A null date is treated as being less than any non-null date

  

import java.util.Calendar;
import java.util.Date;
public class DateUtils {
    
    /**
     * <p>Checks if two dates are on the same day ignoring time.</p>
     * @param date1  the first date, not altered, not null
     * @param date2  the second date, not altered, not null
     * @return true if they represent the same day
     * @throws IllegalArgumentException if either date is <code>null</code>
     */
    public static boolean isSameDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isSameDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if two calendars represent the same day ignoring time.</p>
     * @param cal1  the first calendar, not altered, not null
     * @param cal2  the second calendar, not altered, not null
     * @return true if they represent the same day
     * @throws IllegalArgumentException if either calendar is <code>null</code>
     */
    public static boolean isSameDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        return (cal1.get(Calendar.ERA) == cal2.get(Calendar.ERA) &&
                cal1.get(Calendar.YEAR) == cal2.get(Calendar.YEAR) &&
                cal1.get(Calendar.DAY_OF_YEAR) == cal2.get(Calendar.DAY_OF_YEAR));
    }
    
    /**
     * <p>Checks if a date is today.</p>
     * @param date the date, not altered, not null.
     * @return true if the date is today.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isToday(Date date) {
        return isSameDay(date, Calendar.getInstance().getTime());
    }
    
    /**
     * <p>Checks if a calendar date is today.</p>
     * @param cal  the calendar, not altered, not null
     * @return true if cal date is today
     * @throws IllegalArgumentException if the calendar is <code>null</code>
     */
    public static boolean isToday(Calendar cal) {
        return isSameDay(cal, Calendar.getInstance());
    }
    
    /**
     * <p>Checks if the first date is before the second date ignoring time.</p>
     * @param date1 the first date, not altered, not null
     * @param date2 the second date, not altered, not null
     * @return true if the first date day is before the second date day.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isBeforeDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isBeforeDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if the first calendar date is before the second calendar date ignoring time.</p>
     * @param cal1 the first calendar, not altered, not null.
     * @param cal2 the second calendar, not altered, not null.
     * @return true if cal1 date is before cal2 date ignoring time.
     * @throws IllegalArgumentException if either of the calendars are <code>null</code>
     */
    public static boolean isBeforeDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        if (cal1.get(Calendar.ERA) < cal2.get(Calendar.ERA)) return true;
        if (cal1.get(Calendar.ERA) > cal2.get(Calendar.ERA)) return false;
        if (cal1.get(Calendar.YEAR) < cal2.get(Calendar.YEAR)) return true;
        if (cal1.get(Calendar.YEAR) > cal2.get(Calendar.YEAR)) return false;
        return cal1.get(Calendar.DAY_OF_YEAR) < cal2.get(Calendar.DAY_OF_YEAR);
    }
    
    /**
     * <p>Checks if the first date is after the second date ignoring time.</p>
     * @param date1 the first date, not altered, not null
     * @param date2 the second date, not altered, not null
     * @return true if the first date day is after the second date day.
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isAfterDay(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(date1);
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(date2);
        return isAfterDay(cal1, cal2);
    }
    
    /**
     * <p>Checks if the first calendar date is after the second calendar date ignoring time.</p>
     * @param cal1 the first calendar, not altered, not null.
     * @param cal2 the second calendar, not altered, not null.
     * @return true if cal1 date is after cal2 date ignoring time.
     * @throws IllegalArgumentException if either of the calendars are <code>null</code>
     */
    public static boolean isAfterDay(Calendar cal1, Calendar cal2) {
        if (cal1 == null || cal2 == null) {
            throw new IllegalArgumentException("The dates must not be null");
        }
        if (cal1.get(Calendar.ERA) < cal2.get(Calendar.ERA)) return false;
        if (cal1.get(Calendar.ERA) > cal2.get(Calendar.ERA)) return true;
        if (cal1.get(Calendar.YEAR) < cal2.get(Calendar.YEAR)) return false;
        if (cal1.get(Calendar.YEAR) > cal2.get(Calendar.YEAR)) return true;
        return cal1.get(Calendar.DAY_OF_YEAR) > cal2.get(Calendar.DAY_OF_YEAR);
    }
    
    /**
     * <p>Checks if a date is after today and within a number of days in the future.</p>
     * @param date the date to check, not altered, not null.
     * @param days the number of days.
     * @return true if the date day is after today and within days in the future .
     * @throws IllegalArgumentException if the date is <code>null</code>
     */
    public static boolean isWithinDaysFuture(Date date, int days) {
        if (date == null) {
            throw new IllegalArgumentException("The date must not be null");
        }
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        return isWithinDaysFuture(cal, days);
    }
    
    /**
     * <p>Checks if a calendar date is after today and within a number of days in the future.</p>
     * @param cal the calendar, not altered, not null
     * @param days the number of days.
     * @return true if the calendar date day is after today and within days in the future .
     * @throws IllegalArgumentException if the calendar is <code>null</code>
     */
    public static boolean isWithinDaysFuture(Calendar cal, int days) {
        if (cal == null) {
            throw new IllegalArgumentException("The date must not be null");
        }
        Calendar today = Calendar.getInstance();
        Calendar future = Calendar.getInstance();
        future.add(Calendar.DAY_OF_YEAR, days);
        return (isAfterDay(cal, today) && ! isAfterDay(cal, future));
    }
    
    /** Returns the given date with the time set to the start of the day. */
    public static Date getStart(Date date) {
        return clearTime(date);
    }
    
    /** Returns the given date with the time values cleared. */
    public static Date clearTime(Date date) {
        if (date == null) {
            return null;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.set(Calendar.HOUR_OF_DAY, 0);
        c.set(Calendar.MINUTE, 0);
        c.set(Calendar.SECOND, 0);
        c.set(Calendar.MILLISECOND, 0);
        return c.getTime();
    }    
    /** Determines whether or not a date has any time values (hour, minute, 
     * seconds or millisecondsReturns the given date with the time values cleared. */
    /**
     * Determines whether or not a date has any time values.
     * @param date The date.
     * @return true iff the date is not null and any of the date"s hour, minute,
     * seconds or millisecond values are greater than zero.
     */
    public static boolean hasTime(Date date) {
        if (date == null) {
            return false;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        if (c.get(Calendar.HOUR_OF_DAY) > 0) {
            return true;
        }
        if (c.get(Calendar.MINUTE) > 0) {
            return true;
        }
        if (c.get(Calendar.SECOND) > 0) {
            return true;
        }
        if (c.get(Calendar.MILLISECOND) > 0) {
            return true;
        }
        return false;
    }
    /** Returns the given date with time set to the end of the day */
    public static Date getEnd(Date date) {
        if (date == null) {
            return null;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.set(Calendar.HOUR_OF_DAY, 23);
        c.set(Calendar.MINUTE, 59);
        c.set(Calendar.SECOND, 59);
        c.set(Calendar.MILLISECOND, 999);
        return c.getTime();
    }
    /** 
     * Returns the maximum of two dates. A null date is treated as being less
     * than any non-null date. 
     */
    public static Date max(Date d1, Date d2) {
        if (d1 == null && d2 == null) return null;
        if (d1 == null) return d2;
        if (d2 == null) return d1;
        return (d1.after(d2)) ? d1 : d2;
    }
    
    /** 
     * Returns the minimum of two dates. A null date is treated as being greater
     * than any non-null date. 
     */
    public static Date min(Date d1, Date d2) {
        if (d1 == null && d2 == null) return null;
        if (d1 == null) return d2;
        if (d2 == null) return d1;
        return (d1.before(d2)) ? d1 : d2;
    }
    /** The maximum date possible. */
    public static Date MAX_DATE = new Date(Long.MAX_VALUE);
    
}





Returns the number of days within the fragment.

  
import java.util.Calendar;
import java.util.Date;
import java.util.Iterator;
import java.util.TimeZone;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


/**
 * <p>A suite of utilities surrounding the use of the
 * {@link java.util.Calendar} and {@link java.util.Date} object.</p>
 * 
 * <p>DateUtils contains a lot of common methods considering manipulations
 * of Dates or Calendars. Some methods require some extra explanation.
 * The truncate and round methods could be considered the Math.floor(),
 * Math.ceil() or Math.round versions for dates
 * This way date-fields will be ignored in bottom-up order.
 * As a complement to these methods we"ve introduced some fragment-methods.
 * With these methods the Date-fields will be ignored in top-down order.
 * Since a date without a year is not a valid date, you have to decide in what
 * kind of date-field you want your result, for instance milliseconds or days.
 * </p>
 *   
 *   
 *
 * @author 
 * @author Phil Steitz
 * @author Robert Scholte
 * @since 2.0
 * @version $Id: DateUtils.java 634096 2008-03-06 00:58:11Z niallp $
 */
public class Main {
  
  /**
   * The UTC time zone  (often referred to as GMT).
   */
  public static final TimeZone UTC_TIME_ZONE = TimeZone.getTimeZone("GMT");
  /**
   * Number of milliseconds in a standard second.
   * @since 2.1
   */
  public static final long MILLIS_PER_SECOND = 1000;
  /**
   * Number of milliseconds in a standard minute.
   * @since 2.1
   */
  public static final long MILLIS_PER_MINUTE = 60 * MILLIS_PER_SECOND;
  /**
   * Number of milliseconds in a standard hour.
   * @since 2.1
   */
  public static final long MILLIS_PER_HOUR = 60 * MILLIS_PER_MINUTE;
  /**
   * Number of milliseconds in a standard day.
   * @since 2.1
   */
  public static final long MILLIS_PER_DAY = 24 * MILLIS_PER_HOUR;
  /**
   * This is half a month, so this represents whether a date is in the top
   * or bottom half of the month.
   */
  public final static int SEMI_MONTH = 1001;
  private static final int[][] fields = {
          {Calendar.MILLISECOND},
          {Calendar.SECOND},
          {Calendar.MINUTE},
          {Calendar.HOUR_OF_DAY, Calendar.HOUR},
          {Calendar.DATE, Calendar.DAY_OF_MONTH, Calendar.AM_PM 
              /* Calendar.DAY_OF_YEAR, Calendar.DAY_OF_WEEK, Calendar.DAY_OF_WEEK_IN_MONTH */
          },
          {Calendar.MONTH, DateUtils.SEMI_MONTH},
          {Calendar.YEAR},
          {Calendar.ERA}};
  /**
   * A week range, starting on Sunday.
   */
  public final static int RANGE_WEEK_SUNDAY = 1;
  /**
   * A week range, starting on Monday.
   */
  public final static int RANGE_WEEK_MONDAY = 2;
  /**
   * A week range, starting on the day focused.
   */
  public final static int RANGE_WEEK_RELATIVE = 3;
  /**
   * A week range, centered around the day focused.
   */
  public final static int RANGE_WEEK_CENTER = 4;
  /**
   * A month range, the week starting on Sunday.
   */
  public final static int RANGE_MONTH_SUNDAY = 5;
  /**
   * A month range, the week starting on Monday.
   */
  public final static int RANGE_MONTH_MONDAY = 6;
  
  /**
   * <p>Returns the number of days within the 
   * fragment. All datefields greater than the fragment will be ignored.</p> 
   * 
   * <p>Asking the days of any date will only return the number of days
   * of the current month (resulting in a number between 1 and 31). This 
   * method will retrieve the number of days for any fragment. 
   * For example, if you want to calculate the number of days past this year, 
   * your fragment is Calendar.YEAR. The result will be all days of the 
   * past month(s).</p> 
   * 
   * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both 
   * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY, 
   * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND
   * A fragment less than or equal to a DAY field will return 0.</p> 
   * 
   * <p>
   * <ul>
   *  <li>January 28, 2008 with Calendar.MONTH as fragment will return 28
   *   (equivalent to calendar.get(Calendar.DAY_OF_MONTH))</li>
   *  <li>February 28, 2008 with Calendar.MONTH as fragment will return 28
   *   (equivalent to calendar.get(Calendar.DAY_OF_MONTH))</li>
   *  <li>January 28, 2008 with Calendar.YEAR as fragment will return 28
   *   (equivalent to calendar.get(Calendar.DAY_OF_YEAR))</li>
   *  <li>February 28, 2008 with Calendar.YEAR as fragment will return 59
   *   (equivalent to calendar.get(Calendar.DAY_OF_YEAR))</li>
   *  <li>January 28, 2008 with Calendar.MILLISECOND as fragment will return 0
   *   (a millisecond cannot be split in days)</li>
   * </ul>
   * </p>
   * 
   * @param calendar the calendar to work with, not null
   * @param fragment the Calendar field part of calendar to calculate 
   * @return number of days within the fragment of date
   * @throws IllegalArgumentException if the date is <code>null</code> or 
   * fragment is not supported
   * @since 2.4
   */
  public static long getFragmentInDays(Calendar calendar, int fragment) {
      return getFragment(calendar, fragment, Calendar.DAY_OF_YEAR);
  }
  
  
  /**
   * Date-version for fragment-calculation in any unit
   * 
   * @param date the date to work with, not null
   * @param fragment the Calendar field part of date to calculate 
   * @param unit Calendar field defining the unit
   * @return number of units within the fragment of the date
   * @throws IllegalArgumentException if the date is <code>null</code> or 
   * fragment is not supported
   * @since 2.4
   */
  private static long getFragment(Date date, int fragment, int unit) {
      if(date == null) {
          throw  new IllegalArgumentException("The date must not be null");
      }
      Calendar calendar = Calendar.getInstance();
      calendar.setTime(date);
      return getFragment(calendar, fragment, unit);
  }
  /**
   * Calendar-version for fragment-calculation in any unit
   * 
   * @param calendar the calendar to work with, not null
   * @param fragment the Calendar field part of calendar to calculate 
   * @param unit Calendar field defining the unit
   * @return number of units within the fragment of the calendar
   * @throws IllegalArgumentException if the date is <code>null</code> or 
   * fragment is not supported
   * @since 2.4
   */
  private static long getFragment(Calendar calendar, int fragment, int unit) {
      if(calendar == null) {
          throw  new IllegalArgumentException("The date must not be null"); 
      }
      long millisPerUnit = getMillisPerUnit(unit);
      long result = 0;
      
      // Fragments bigger than a day require a breakdown to days
      switch (fragment) {
          case Calendar.YEAR:
              result += (calendar.get(Calendar.DAY_OF_YEAR) * MILLIS_PER_DAY) / millisPerUnit;
              break;
          case Calendar.MONTH:
              result += (calendar.get(Calendar.DAY_OF_MONTH) * MILLIS_PER_DAY) / millisPerUnit;
              break;
      }
      switch (fragment) {
          // Number of days already calculated for these cases
          case Calendar.YEAR:
          case Calendar.MONTH:
          
          // The rest of the valid cases
          case Calendar.DAY_OF_YEAR:
          case Calendar.DATE:
              result += (calendar.get(Calendar.HOUR_OF_DAY) * MILLIS_PER_HOUR) / millisPerUnit;
          case Calendar.HOUR_OF_DAY:
              result += (calendar.get(Calendar.MINUTE) * MILLIS_PER_MINUTE) / millisPerUnit;
          case Calendar.MINUTE:
              result += (calendar.get(Calendar.SECOND) * MILLIS_PER_SECOND) / millisPerUnit;
          case Calendar.SECOND:
              result += (calendar.get(Calendar.MILLISECOND) * 1) / millisPerUnit;
              break;
          case Calendar.MILLISECOND: break;//never useful
              default: throw new IllegalArgumentException("The fragment " + fragment + " is not supported");
      }
      return result;
  }
  /**
   * Returns the number of millis of a datefield, if this is a constant value
   * 
   * @param unit A Calendar field which is a valid unit for a fragment
   * @return number of millis
   * @throws IllegalArgumentException if date can"t be represented in millisenconds
   * @since 2.4 
   */
  private static long getMillisPerUnit(int unit) {
      long result = Long.MAX_VALUE;
      switch (unit) {
          case Calendar.DAY_OF_YEAR:
          case Calendar.DATE:
              result = MILLIS_PER_DAY;
              break;
          case Calendar.HOUR_OF_DAY:
              result = MILLIS_PER_HOUR;
              break;
          case Calendar.MINUTE:
              result = MILLIS_PER_MINUTE;
              break;
          case Calendar.SECOND:
              result = MILLIS_PER_SECOND;
              break;
          case Calendar.MILLISECOND:
              result = 1;
              break;
          default: throw new IllegalArgumentException("The unit " + unit + " cannot be represented is milleseconds");
      }
      return result;
  }
}





Returns the number of hours within the fragment.

  
import java.util.Calendar;
import java.util.Date;
import java.util.Iterator;
import java.util.TimeZone;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


/**
 * <p>A suite of utilities surrounding the use of the
 * {@link java.util.Calendar} and {@link java.util.Date} object.</p>
 * 
 * <p>DateUtils contains a lot of common methods considering manipulations
 * of Dates or Calendars. Some methods require some extra explanation.
 * The truncate and round methods could be considered the Math.floor(),
 * Math.ceil() or Math.round versions for dates
 * This way date-fields will be ignored in bottom-up order.
 * As a complement to these methods we"ve introduced some fragment-methods.
 * With these methods the Date-fields will be ignored in top-down order.
 * Since a date without a year is not a valid date, you have to decide in what
 * kind of date-field you want your result, for instance milliseconds or days.
 * </p>
 *   
 *   
 *
 * @author 
 * @author Phil Steitz
 * @author Robert Scholte
 * @since 2.0
 * @version $Id: DateUtils.java 634096 2008-03-06 00:58:11Z niallp $
 */
public class Main {
  
  /**
   * The UTC time zone  (often referred to as GMT).
   */
  public static final TimeZone UTC_TIME_ZONE = TimeZone.getTimeZone("GMT");
  /**
   * Number of milliseconds in a standard second.
   * @since 2.1
   */
  public static final long MILLIS_PER_SECOND = 1000;
  /**
   * Number of milliseconds in a standard minute.
   * @since 2.1
   */
  public static final long MILLIS_PER_MINUTE = 60 * MILLIS_PER_SECOND;
  /**
   * Number of milliseconds in a standard hour.
   * @since 2.1
   */
  public static final long MILLIS_PER_HOUR = 60 * MILLIS_PER_MINUTE;
  /**
   * Number of milliseconds in a standard day.
   * @since 2.1
   */
  public static final long MILLIS_PER_DAY = 24 * MILLIS_PER_HOUR;
  /**
   * This is half a month, so this represents whether a date is in the top
   * or bottom half of the month.
   */
  public final static int SEMI_MONTH = 1001;
  private static final int[][] fields = {
          {Calendar.MILLISECOND},
          {Calendar.SECOND},
          {Calendar.MINUTE},
          {Calendar.HOUR_OF_DAY, Calendar.HOUR},
          {Calendar.DATE, Calendar.DAY_OF_MONTH, Calendar.AM_PM 
              /* Calendar.DAY_OF_YEAR, Calendar.DAY_OF_WEEK, Calendar.DAY_OF_WEEK_IN_MONTH */
          },
          {Calendar.MONTH, DateUtils.SEMI_MONTH},
          {Calendar.YEAR},
          {Calendar.ERA}};
  /**
   * A week range, starting on Sunday.
   */
  public final static int RANGE_WEEK_SUNDAY = 1;
  /**
   * A week range, starting on Monday.
   */
  public final static int RANGE_WEEK_MONDAY = 2;
  /**
   * A week range, starting on the day focused.
   */
  public final static int RANGE_WEEK_RELATIVE = 3;
  /**
   * A week range, centered around the day focused.
   */
  public final static int RANGE_WEEK_CENTER = 4;
  /**
   * A month range, the week starting on Sunday.
   */
  public final static int RANGE_MONTH_SUNDAY = 5;
  /**
   * A month range, the week starting on Monday.
   */
  public final static int RANGE_MONTH_MONDAY = 6;
  
  
  /**
   * <p>Returns the number of hours within the 
   * fragment. All datefields greater than the fragment will be ignored.</p> 
   * 
   * <p>Asking the hours of any date will only return the number of hours
   * of the current day (resulting in a number between 0 and 23). This 
   * method will retrieve the number of hours for any fragment. 
   * For example, if you want to calculate the number of hours past this month, 
   * your fragment is Calendar.MONTH. The result will be all hours of the 
   * past day(s).</p> 
   * 
   * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both 
   * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY, 
   * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND
   * A fragment less than or equal to a HOUR field will return 0.</p> 
   * 
   * <p>
   * <ul>
   *  <li>January 1, 2008 7:15:10.538 with Calendar.DAY_OF_YEAR as fragment will return 7
   *   (equivalent to deprecated date.getHours())</li>
   *  <li>January 6, 2008 7:15:10.538 with Calendar.DAY_OF_YEAR as fragment will return 7
   *   (equivalent to deprecated date.getHours())</li>
   *  <li>January 1, 2008 7:15:10.538 with Calendar.MONTH as fragment will return 7</li>
   *  <li>January 6, 2008 7:15:10.538 with Calendar.MONTH as fragment will return 127 (5*24 + 7)</li>
   *  <li>January 16, 2008 7:15:10.538 with Calendar.MILLISECOND as fragment will return 0
   *   (a millisecond cannot be split in hours)</li>
   * </ul>
   * </p>
   * 
   * @param date the date to work with, not null
   * @param fragment the Calendar field part of date to calculate 
   * @return number of hours within the fragment of date
   * @throws IllegalArgumentException if the date is <code>null</code> or 
   * fragment is not supported
   * @since 2.4
   */
  public static long getFragmentInHours(Date date, int fragment) {
      return getFragment(date, fragment, Calendar.HOUR_OF_DAY);
  }
  
  
  
  /**
   * Date-version for fragment-calculation in any unit
   * 
   * @param date the date to work with, not null
   * @param fragment the Calendar field part of date to calculate 
   * @param unit Calendar field defining the unit
   * @return number of units within the fragment of the date
   * @throws IllegalArgumentException if the date is <code>null</code> or 
   * fragment is not supported
   * @since 2.4
   */
  private static long getFragment(Date date, int fragment, int unit) {
      if(date == null) {
          throw  new IllegalArgumentException("The date must not be null");
      }
      Calendar calendar = Calendar.getInstance();
      calendar.setTime(date);
      return getFragment(calendar, fragment, unit);
  }
  /**
   * Calendar-version for fragment-calculation in any unit
   * 
   * @param calendar the calendar to work with, not null
   * @param fragment the Calendar field part of calendar to calculate 
   * @param unit Calendar field defining the unit
   * @return number of units within the fragment of the calendar
   * @throws IllegalArgumentException if the date is <code>null</code> or 
   * fragment is not supported
   * @since 2.4
   */
  private static long getFragment(Calendar calendar, int fragment, int unit) {
      if(calendar == null) {
          throw  new IllegalArgumentException("The date must not be null"); 
      }
      long millisPerUnit = getMillisPerUnit(unit);
      long result = 0;
      
      // Fragments bigger than a day require a breakdown to days
      switch (fragment) {
          case Calendar.YEAR:
              result += (calendar.get(Calendar.DAY_OF_YEAR) * MILLIS_PER_DAY) / millisPerUnit;
              break;
          case Calendar.MONTH:
              result += (calendar.get(Calendar.DAY_OF_MONTH) * MILLIS_PER_DAY) / millisPerUnit;
              break;
      }
      switch (fragment) {
          // Number of days already calculated for these cases
          case Calendar.YEAR:
          case Calendar.MONTH:
          
          // The rest of the valid cases
          case Calendar.DAY_OF_YEAR:
          case Calendar.DATE:
              result += (calendar.get(Calendar.HOUR_OF_DAY) * MILLIS_PER_HOUR) / millisPerUnit;
          case Calendar.HOUR_OF_DAY:
              result += (calendar.get(Calendar.MINUTE) * MILLIS_PER_MINUTE) / millisPerUnit;
          case Calendar.MINUTE:
              result += (calendar.get(Calendar.SECOND) * MILLIS_PER_SECOND) / millisPerUnit;
          case Calendar.SECOND:
              result += (calendar.get(Calendar.MILLISECOND) * 1) / millisPerUnit;
              break;
          case Calendar.MILLISECOND: break;//never useful
              default: throw new IllegalArgumentException("The fragment " + fragment + " is not supported");
      }
      return result;
  }
  /**
   * Returns the number of millis of a datefield, if this is a constant value
   * 
   * @param unit A Calendar field which is a valid unit for a fragment
   * @return number of millis
   * @throws IllegalArgumentException if date can"t be represented in millisenconds
   * @since 2.4 
   */
  private static long getMillisPerUnit(int unit) {
      long result = Long.MAX_VALUE;
      switch (unit) {
          case Calendar.DAY_OF_YEAR:
          case Calendar.DATE:
              result = MILLIS_PER_DAY;
              break;
          case Calendar.HOUR_OF_DAY:
              result = MILLIS_PER_HOUR;
              break;
          case Calendar.MINUTE:
              result = MILLIS_PER_MINUTE;
              break;
          case Calendar.SECOND:
              result = MILLIS_PER_SECOND;
              break;
          case Calendar.MILLISECOND:
              result = 1;
              break;
          default: throw new IllegalArgumentException("The unit " + unit + " cannot be represented is milleseconds");
      }
      return result;
  }
}





Returns the number of milliseconds within the fragment.

  
import java.util.Calendar;
import java.util.Date;
import java.util.Iterator;
import java.util.TimeZone;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


/**
 * <p>A suite of utilities surrounding the use of the
 * {@link java.util.Calendar} and {@link java.util.Date} object.</p>
 * 
 * <p>DateUtils contains a lot of common methods considering manipulations
 * of Dates or Calendars. Some methods require some extra explanation.
 * The truncate and round methods could be considered the Math.floor(),
 * Math.ceil() or Math.round versions for dates
 * This way date-fields will be ignored in bottom-up order.
 * As a complement to these methods we"ve introduced some fragment-methods.
 * With these methods the Date-fields will be ignored in top-down order.
 * Since a date without a year is not a valid date, you have to decide in what
 * kind of date-field you want your result, for instance milliseconds or days.
 * </p>
 *   
 *   
 *
 * @author 
 * @author Phil Steitz
 * @author Robert Scholte
 * @since 2.0
 * @version $Id: DateUtils.java 634096 2008-03-06 00:58:11Z niallp $
 */
public class Main {
  
  /**
   * The UTC time zone  (often referred to as GMT).
   */
  public static final TimeZone UTC_TIME_ZONE = TimeZone.getTimeZone("GMT");
  /**
   * Number of milliseconds in a standard second.
   * @since 2.1
   */
  public static final long MILLIS_PER_SECOND = 1000;
  /**
   * Number of milliseconds in a standard minute.
   * @since 2.1
   */
  public static final long MILLIS_PER_MINUTE = 60 * MILLIS_PER_SECOND;
  /**
   * Number of milliseconds in a standard hour.
   * @since 2.1
   */
  public static final long MILLIS_PER_HOUR = 60 * MILLIS_PER_MINUTE;
  /**
   * Number of milliseconds in a standard day.
   * @since 2.1
   */
  public static final long MILLIS_PER_DAY = 24 * MILLIS_PER_HOUR;
  /**
   * This is half a month, so this represents whether a date is in the top
   * or bottom half of the month.
   */
  public final static int SEMI_MONTH = 1001;
  private static final int[][] fields = {
          {Calendar.MILLISECOND},
          {Calendar.SECOND},
          {Calendar.MINUTE},
          {Calendar.HOUR_OF_DAY, Calendar.HOUR},
          {Calendar.DATE, Calendar.DAY_OF_MONTH, Calendar.AM_PM 
              /* Calendar.DAY_OF_YEAR, Calendar.DAY_OF_WEEK, Calendar.DAY_OF_WEEK_IN_MONTH */
          },
          {Calendar.MONTH, DateUtils.SEMI_MONTH},
          {Calendar.YEAR},
          {Calendar.ERA}};
  /**
   * A week range, starting on Sunday.
   */
  public final static int RANGE_WEEK_SUNDAY = 1;
  /**
   * A week range, starting on Monday.
   */
  public final static int RANGE_WEEK_MONDAY = 2;
  /**
   * A week range, starting on the day focused.
   */
  public final static int RANGE_WEEK_RELATIVE = 3;
  /**
   * A week range, centered around the day focused.
   */
  public final static int RANGE_WEEK_CENTER = 4;
  /**
   * A month range, the week starting on Sunday.
   */
  public final static int RANGE_MONTH_SUNDAY = 5;
  /**
   * A month range, the week starting on Monday.
   */
  public final static int RANGE_MONTH_MONDAY = 6;
  

  /**
   * <p>Returns the number of milliseconds within the 
   * fragment. All datefields greater than the fragment will be ignored.</p> 
   * 
   * <p>Asking the milliseconds of any date will only return the number of milliseconds
   * of the current second (resulting in a number between 0 and 999). This 
   * method will retrieve the number of milliseconds for any fragment. 
   * For example, if you want to calculate the number of seconds past today, 
   * your fragment is Calendar.DATE or Calendar.DAY_OF_YEAR. The result will
   * be all seconds of the past hour(s), minutes(s) and second(s).</p> 
   * 
   * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both 
   * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY, 
   * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND
   * A fragment less than or equal to a MILLISECOND field will return 0.</p> 
   * 
   * <p>
   * <ul>
   *  <li>January 1, 2008 7:15:10.538 with Calendar.SECOND as fragment will return 538
   *   (equivalent to calendar.get(Calendar.MILLISECOND))</li>
   *  <li>January 6, 2008 7:15:10.538 with Calendar.SECOND as fragment will return 538
   *   (equivalent to calendar.get(Calendar.MILLISECOND))</li>
   *  <li>January 6, 2008 7:15:10.538 with Calendar.MINUTE as fragment will return 10538
   *   (10*1000 + 538)</li>
   *  <li>January 16, 2008 7:15:10.538 with Calendar.MILLISECOND as fragment will return 0
   *   (a millisecond cannot be split in milliseconds)</li>
   * </ul>
   * </p>
   * 
   * @param calendar the calendar to work with, not null
   * @param fragment the Calendar field part of calendar to calculate 
   * @return number of milliseconds within the fragment of date
   * @throws IllegalArgumentException if the date is <code>null</code> or 
   * fragment is not supported
   * @since 2.4
   */
public static long getFragmentInMilliseconds(Calendar calendar, int fragment) {
  return getFragment(calendar, fragment, Calendar.MILLISECOND);
}
  
  /**
   * Date-version for fragment-calculation in any unit
   * 
   * @param date the date to work with, not null
   * @param fragment the Calendar field part of date to calculate 
   * @param unit Calendar field defining the unit
   * @return number of units within the fragment of the date
   * @throws IllegalArgumentException if the date is <code>null</code> or 
   * fragment is not supported
   * @since 2.4
   */
  private static long getFragment(Date date, int fragment, int unit) {
      if(date == null) {
          throw  new IllegalArgumentException("The date must not be null");
      }
      Calendar calendar = Calendar.getInstance();
      calendar.setTime(date);
      return getFragment(calendar, fragment, unit);
  }
  /**
   * Calendar-version for fragment-calculation in any unit
   * 
   * @param calendar the calendar to work with, not null
   * @param fragment the Calendar field part of calendar to calculate 
   * @param unit Calendar field defining the unit
   * @return number of units within the fragment of the calendar
   * @throws IllegalArgumentException if the date is <code>null</code> or 
   * fragment is not supported
   * @since 2.4
   */
  private static long getFragment(Calendar calendar, int fragment, int unit) {
      if(calendar == null) {
          throw  new IllegalArgumentException("The date must not be null"); 
      }
      long millisPerUnit = getMillisPerUnit(unit);
      long result = 0;
      
      // Fragments bigger than a day require a breakdown to days
      switch (fragment) {
          case Calendar.YEAR:
              result += (calendar.get(Calendar.DAY_OF_YEAR) * MILLIS_PER_DAY) / millisPerUnit;
              break;
          case Calendar.MONTH:
              result += (calendar.get(Calendar.DAY_OF_MONTH) * MILLIS_PER_DAY) / millisPerUnit;
              break;
      }
      switch (fragment) {
          // Number of days already calculated for these cases
          case Calendar.YEAR:
          case Calendar.MONTH:
          
          // The rest of the valid cases
          case Calendar.DAY_OF_YEAR:
          case Calendar.DATE:
              result += (calendar.get(Calendar.HOUR_OF_DAY) * MILLIS_PER_HOUR) / millisPerUnit;
          case Calendar.HOUR_OF_DAY:
              result += (calendar.get(Calendar.MINUTE) * MILLIS_PER_MINUTE) / millisPerUnit;
          case Calendar.MINUTE:
              result += (calendar.get(Calendar.SECOND) * MILLIS_PER_SECOND) / millisPerUnit;
          case Calendar.SECOND:
              result += (calendar.get(Calendar.MILLISECOND) * 1) / millisPerUnit;
              break;
          case Calendar.MILLISECOND: break;//never useful
              default: throw new IllegalArgumentException("The fragment " + fragment + " is not supported");
      }
      return result;
  }
  /**
   * Returns the number of millis of a datefield, if this is a constant value
   * 
   * @param unit A Calendar field which is a valid unit for a fragment
   * @return number of millis
   * @throws IllegalArgumentException if date can"t be represented in millisenconds
   * @since 2.4 
   */
  private static long getMillisPerUnit(int unit) {
      long result = Long.MAX_VALUE;
      switch (unit) {
          case Calendar.DAY_OF_YEAR:
          case Calendar.DATE:
              result = MILLIS_PER_DAY;
              break;
          case Calendar.HOUR_OF_DAY:
              result = MILLIS_PER_HOUR;
              break;
          case Calendar.MINUTE:
              result = MILLIS_PER_MINUTE;
              break;
          case Calendar.SECOND:
              result = MILLIS_PER_SECOND;
              break;
          case Calendar.MILLISECOND:
              result = 1;
              break;
          default: throw new IllegalArgumentException("The unit " + unit + " cannot be represented is milleseconds");
      }
      return result;
  }
}





Returns the number of minutes within the fragment.

  
import java.util.Calendar;
import java.util.Date;
import java.util.Iterator;
import java.util.TimeZone;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


/**
 * <p>A suite of utilities surrounding the use of the
 * {@link java.util.Calendar} and {@link java.util.Date} object.</p>
 * 
 * <p>DateUtils contains a lot of common methods considering manipulations
 * of Dates or Calendars. Some methods require some extra explanation.
 * The truncate and round methods could be considered the Math.floor(),
 * Math.ceil() or Math.round versions for dates
 * This way date-fields will be ignored in bottom-up order.
 * As a complement to these methods we"ve introduced some fragment-methods.
 * With these methods the Date-fields will be ignored in top-down order.
 * Since a date without a year is not a valid date, you have to decide in what
 * kind of date-field you want your result, for instance milliseconds or days.
 * </p>
 *   
 *   
 *
 * @author 
 * @author Phil Steitz
 * @author Robert Scholte
 * @since 2.0
 * @version $Id: DateUtils.java 634096 2008-03-06 00:58:11Z niallp $
 */
public class Main {
  
  /**
   * The UTC time zone  (often referred to as GMT).
   */
  public static final TimeZone UTC_TIME_ZONE = TimeZone.getTimeZone("GMT");
  /**
   * Number of milliseconds in a standard second.
   * @since 2.1
   */
  public static final long MILLIS_PER_SECOND = 1000;
  /**
   * Number of milliseconds in a standard minute.
   * @since 2.1
   */
  public static final long MILLIS_PER_MINUTE = 60 * MILLIS_PER_SECOND;
  /**
   * Number of milliseconds in a standard hour.
   * @since 2.1
   */
  public static final long MILLIS_PER_HOUR = 60 * MILLIS_PER_MINUTE;
  /**
   * Number of milliseconds in a standard day.
   * @since 2.1
   */
  public static final long MILLIS_PER_DAY = 24 * MILLIS_PER_HOUR;
  /**
   * This is half a month, so this represents whether a date is in the top
   * or bottom half of the month.
   */
  public final static int SEMI_MONTH = 1001;
  private static final int[][] fields = {
          {Calendar.MILLISECOND},
          {Calendar.SECOND},
          {Calendar.MINUTE},
          {Calendar.HOUR_OF_DAY, Calendar.HOUR},
          {Calendar.DATE, Calendar.DAY_OF_MONTH, Calendar.AM_PM 
              /* Calendar.DAY_OF_YEAR, Calendar.DAY_OF_WEEK, Calendar.DAY_OF_WEEK_IN_MONTH */
          },
          {Calendar.MONTH, DateUtils.SEMI_MONTH},
          {Calendar.YEAR},
          {Calendar.ERA}};
  /**
   * A week range, starting on Sunday.
   */
  public final static int RANGE_WEEK_SUNDAY = 1;
  /**
   * A week range, starting on Monday.
   */
  public final static int RANGE_WEEK_MONDAY = 2;
  /**
   * A week range, starting on the day focused.
   */
  public final static int RANGE_WEEK_RELATIVE = 3;
  /**
   * A week range, centered around the day focused.
   */
  public final static int RANGE_WEEK_CENTER = 4;
  /**
   * A month range, the week starting on Sunday.
   */
  public final static int RANGE_MONTH_SUNDAY = 5;
  /**
   * A month range, the week starting on Monday.
   */
  public final static int RANGE_MONTH_MONDAY = 6;
  
  
  /**
   * <p>Returns the number of minutes within the 
   * fragment. All datefields greater than the fragment will be ignored.</p> 
   * 
   * <p>Asking the minutes of any date will only return the number of minutes
   * of the current hour (resulting in a number between 0 and 59). This 
   * method will retrieve the number of minutes for any fragment. 
   * For example, if you want to calculate the number of minutes past this month, 
   * your fragment is Calendar.MONTH. The result will be all minutes of the 
   * past day(s) and hour(s).</p> 
   * 
   * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both 
   * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY, 
   * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND
   * A fragment less than or equal to a MINUTE field will return 0.</p> 
   * 
   * <p>
   * <ul>
   *  <li>January 1, 2008 7:15:10.538 with Calendar.HOUR_OF_DAY as fragment will return 15
   *   (equivalent to deprecated date.getMinutes())</li>
   *  <li>January 6, 2008 7:15:10.538 with Calendar.HOUR_OF_DAY as fragment will return 15
   *   (equivalent to deprecated date.getMinutes())</li>
   *  <li>January 1, 2008 7:15:10.538 with Calendar.MONTH as fragment will return 15</li>
   *  <li>January 6, 2008 7:15:10.538 with Calendar.MONTH as fragment will return 435 (7*60 + 15)</li>
   *  <li>January 16, 2008 7:15:10.538 with Calendar.MILLISECOND as fragment will return 0
   *   (a millisecond cannot be split in minutes)</li>
   * </ul>
   * </p>
   * 
   * @param date the date to work with, not null
   * @param fragment the Calendar field part of date to calculate 
   * @return number of minutes within the fragment of date
   * @throws IllegalArgumentException if the date is <code>null</code> or 
   * fragment is not supported
   * @since 2.4
   */
  public static long getFragmentInMinutes(Date date, int fragment) {
      return getFragment(date, fragment, Calendar.MINUTE);
  }
  
  
  /**
   * Date-version for fragment-calculation in any unit
   * 
   * @param date the date to work with, not null
   * @param fragment the Calendar field part of date to calculate 
   * @param unit Calendar field defining the unit
   * @return number of units within the fragment of the date
   * @throws IllegalArgumentException if the date is <code>null</code> or 
   * fragment is not supported
   * @since 2.4
   */
  private static long getFragment(Date date, int fragment, int unit) {
      if(date == null) {
          throw  new IllegalArgumentException("The date must not be null");
      }
      Calendar calendar = Calendar.getInstance();
      calendar.setTime(date);
      return getFragment(calendar, fragment, unit);
  }
  /**
   * Calendar-version for fragment-calculation in any unit
   * 
   * @param calendar the calendar to work with, not null
   * @param fragment the Calendar field part of calendar to calculate 
   * @param unit Calendar field defining the unit
   * @return number of units within the fragment of the calendar
   * @throws IllegalArgumentException if the date is <code>null</code> or 
   * fragment is not supported
   * @since 2.4
   */
  private static long getFragment(Calendar calendar, int fragment, int unit) {
      if(calendar == null) {
          throw  new IllegalArgumentException("The date must not be null"); 
      }
      long millisPerUnit = getMillisPerUnit(unit);
      long result = 0;
      
      // Fragments bigger than a day require a breakdown to days
      switch (fragment) {
          case Calendar.YEAR:
              result += (calendar.get(Calendar.DAY_OF_YEAR) * MILLIS_PER_DAY) / millisPerUnit;
              break;
          case Calendar.MONTH:
              result += (calendar.get(Calendar.DAY_OF_MONTH) * MILLIS_PER_DAY) / millisPerUnit;
              break;
      }
      switch (fragment) {
          // Number of days already calculated for these cases
          case Calendar.YEAR:
          case Calendar.MONTH:
          
          // The rest of the valid cases
          case Calendar.DAY_OF_YEAR:
          case Calendar.DATE:
              result += (calendar.get(Calendar.HOUR_OF_DAY) * MILLIS_PER_HOUR) / millisPerUnit;
          case Calendar.HOUR_OF_DAY:
              result += (calendar.get(Calendar.MINUTE) * MILLIS_PER_MINUTE) / millisPerUnit;
          case Calendar.MINUTE:
              result += (calendar.get(Calendar.SECOND) * MILLIS_PER_SECOND) / millisPerUnit;
          case Calendar.SECOND:
              result += (calendar.get(Calendar.MILLISECOND) * 1) / millisPerUnit;
              break;
          case Calendar.MILLISECOND: break;//never useful
              default: throw new IllegalArgumentException("The fragment " + fragment + " is not supported");
      }
      return result;
  }
  /**
   * Returns the number of millis of a datefield, if this is a constant value
   * 
   * @param unit A Calendar field which is a valid unit for a fragment
   * @return number of millis
   * @throws IllegalArgumentException if date can"t be represented in millisenconds
   * @since 2.4 
   */
  private static long getMillisPerUnit(int unit) {
      long result = Long.MAX_VALUE;
      switch (unit) {
          case Calendar.DAY_OF_YEAR:
          case Calendar.DATE:
              result = MILLIS_PER_DAY;
              break;
          case Calendar.HOUR_OF_DAY:
              result = MILLIS_PER_HOUR;
              break;
          case Calendar.MINUTE:
              result = MILLIS_PER_MINUTE;
              break;
          case Calendar.SECOND:
              result = MILLIS_PER_SECOND;
              break;
          case Calendar.MILLISECOND:
              result = 1;
              break;
          default: throw new IllegalArgumentException("The unit " + unit + " cannot be represented is milleseconds");
      }
      return result;
  }
}





Returns the number of seconds within the fragment.

  
import java.util.Calendar;
import java.util.Date;
import java.util.Iterator;
import java.util.TimeZone;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


/**
 * <p>A suite of utilities surrounding the use of the
 * {@link java.util.Calendar} and {@link java.util.Date} object.</p>
 * 
 * <p>DateUtils contains a lot of common methods considering manipulations
 * of Dates or Calendars. Some methods require some extra explanation.
 * The truncate and round methods could be considered the Math.floor(),
 * Math.ceil() or Math.round versions for dates
 * This way date-fields will be ignored in bottom-up order.
 * As a complement to these methods we"ve introduced some fragment-methods.
 * With these methods the Date-fields will be ignored in top-down order.
 * Since a date without a year is not a valid date, you have to decide in what
 * kind of date-field you want your result, for instance milliseconds or days.
 * </p>
 *   
 *   
 *
 * @author 
 * @author Phil Steitz
 * @author Robert Scholte
 * @since 2.0
 * @version $Id: DateUtils.java 634096 2008-03-06 00:58:11Z niallp $
 */
public class Main {
  
  /**
   * The UTC time zone  (often referred to as GMT).
   */
  public static final TimeZone UTC_TIME_ZONE = TimeZone.getTimeZone("GMT");
  /**
   * Number of milliseconds in a standard second.
   * @since 2.1
   */
  public static final long MILLIS_PER_SECOND = 1000;
  /**
   * Number of milliseconds in a standard minute.
   * @since 2.1
   */
  public static final long MILLIS_PER_MINUTE = 60 * MILLIS_PER_SECOND;
  /**
   * Number of milliseconds in a standard hour.
   * @since 2.1
   */
  public static final long MILLIS_PER_HOUR = 60 * MILLIS_PER_MINUTE;
  /**
   * Number of milliseconds in a standard day.
   * @since 2.1
   */
  public static final long MILLIS_PER_DAY = 24 * MILLIS_PER_HOUR;
  /**
   * This is half a month, so this represents whether a date is in the top
   * or bottom half of the month.
   */
  public final static int SEMI_MONTH = 1001;
  private static final int[][] fields = {
          {Calendar.MILLISECOND},
          {Calendar.SECOND},
          {Calendar.MINUTE},
          {Calendar.HOUR_OF_DAY, Calendar.HOUR},
          {Calendar.DATE, Calendar.DAY_OF_MONTH, Calendar.AM_PM 
              /* Calendar.DAY_OF_YEAR, Calendar.DAY_OF_WEEK, Calendar.DAY_OF_WEEK_IN_MONTH */
          },
          {Calendar.MONTH, DateUtils.SEMI_MONTH},
          {Calendar.YEAR},
          {Calendar.ERA}};
  /**
   * A week range, starting on Sunday.
   */
  public final static int RANGE_WEEK_SUNDAY = 1;
  /**
   * A week range, starting on Monday.
   */
  public final static int RANGE_WEEK_MONDAY = 2;
  /**
   * A week range, starting on the day focused.
   */
  public final static int RANGE_WEEK_RELATIVE = 3;
  /**
   * A week range, centered around the day focused.
   */
  public final static int RANGE_WEEK_CENTER = 4;
  /**
   * A month range, the week starting on Sunday.
   */
  public final static int RANGE_MONTH_SUNDAY = 5;
  /**
   * A month range, the week starting on Monday.
   */
  public final static int RANGE_MONTH_MONDAY = 6;
  
  
  
  /**
   * <p>Returns the number of seconds within the 
   * fragment. All datefields greater than the fragment will be ignored.</p> 
   * 
   * <p>Asking the seconds of any date will only return the number of seconds
   * of the current minute (resulting in a number between 0 and 59). This 
   * method will retrieve the number of seconds for any fragment. 
   * For example, if you want to calculate the number of seconds past today, 
   * your fragment is Calendar.DATE or Calendar.DAY_OF_YEAR. The result will
   * be all seconds of the past hour(s) and minutes(s).</p> 
   * 
   * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both 
   * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY, 
   * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND
   * A fragment less than or equal to a SECOND field will return 0.</p> 
   * 
   * <p>
   * <ul>
   *  <li>January 1, 2008 7:15:10.538 with Calendar.MINUTE as fragment will return 10
   *   (equivalent to deprecated date.getSeconds())</li>
   *  <li>January 6, 2008 7:15:10.538 with Calendar.MINUTE as fragment will return 10
   *   (equivalent to deprecated date.getSeconds())</li>
   *  <li>January 6, 2008 7:15:10.538 with Calendar.DAY_OF_YEAR as fragment will return 26110
   *   (7*3600 + 15*60 + 10)</li>
   *  <li>January 16, 2008 7:15:10.538 with Calendar.MILLISECOND as fragment will return 0
   *   (a millisecond cannot be split in seconds)</li>
   * </ul>
   * </p>
   * 
   * @param date the date to work with, not null
   * @param fragment the Calendar field part of date to calculate 
   * @return number of seconds within the fragment of date
   * @throws IllegalArgumentException if the date is <code>null</code> or
   * fragment is not supported
   * @since 2.4
   */
  public static long getFragmentInSeconds(Date date, int fragment) {
      return getFragment(date, fragment, Calendar.SECOND);
  }
  
  
  /**
   * Date-version for fragment-calculation in any unit
   * 
   * @param date the date to work with, not null
   * @param fragment the Calendar field part of date to calculate 
   * @param unit Calendar field defining the unit
   * @return number of units within the fragment of the date
   * @throws IllegalArgumentException if the date is <code>null</code> or 
   * fragment is not supported
   * @since 2.4
   */
  private static long getFragment(Date date, int fragment, int unit) {
      if(date == null) {
          throw  new IllegalArgumentException("The date must not be null");
      }
      Calendar calendar = Calendar.getInstance();
      calendar.setTime(date);
      return getFragment(calendar, fragment, unit);
  }
  /**
   * Calendar-version for fragment-calculation in any unit
   * 
   * @param calendar the calendar to work with, not null
   * @param fragment the Calendar field part of calendar to calculate 
   * @param unit Calendar field defining the unit
   * @return number of units within the fragment of the calendar
   * @throws IllegalArgumentException if the date is <code>null</code> or 
   * fragment is not supported
   * @since 2.4
   */
  private static long getFragment(Calendar calendar, int fragment, int unit) {
      if(calendar == null) {
          throw  new IllegalArgumentException("The date must not be null"); 
      }
      long millisPerUnit = getMillisPerUnit(unit);
      long result = 0;
      
      // Fragments bigger than a day require a breakdown to days
      switch (fragment) {
          case Calendar.YEAR:
              result += (calendar.get(Calendar.DAY_OF_YEAR) * MILLIS_PER_DAY) / millisPerUnit;
              break;
          case Calendar.MONTH:
              result += (calendar.get(Calendar.DAY_OF_MONTH) * MILLIS_PER_DAY) / millisPerUnit;
              break;
      }
      switch (fragment) {
          // Number of days already calculated for these cases
          case Calendar.YEAR:
          case Calendar.MONTH:
          
          // The rest of the valid cases
          case Calendar.DAY_OF_YEAR:
          case Calendar.DATE:
              result += (calendar.get(Calendar.HOUR_OF_DAY) * MILLIS_PER_HOUR) / millisPerUnit;
          case Calendar.HOUR_OF_DAY:
              result += (calendar.get(Calendar.MINUTE) * MILLIS_PER_MINUTE) / millisPerUnit;
          case Calendar.MINUTE:
              result += (calendar.get(Calendar.SECOND) * MILLIS_PER_SECOND) / millisPerUnit;
          case Calendar.SECOND:
              result += (calendar.get(Calendar.MILLISECOND) * 1) / millisPerUnit;
              break;
          case Calendar.MILLISECOND: break;//never useful
              default: throw new IllegalArgumentException("The fragment " + fragment + " is not supported");
      }
      return result;
  }
  /**
   * Returns the number of millis of a datefield, if this is a constant value
   * 
   * @param unit A Calendar field which is a valid unit for a fragment
   * @return number of millis
   * @throws IllegalArgumentException if date can"t be represented in millisenconds
   * @since 2.4 
   */
  private static long getMillisPerUnit(int unit) {
      long result = Long.MAX_VALUE;
      switch (unit) {
          case Calendar.DAY_OF_YEAR:
          case Calendar.DATE:
              result = MILLIS_PER_DAY;
              break;
          case Calendar.HOUR_OF_DAY:
              result = MILLIS_PER_HOUR;
              break;
          case Calendar.MINUTE:
              result = MILLIS_PER_MINUTE;
              break;
          case Calendar.SECOND:
              result = MILLIS_PER_SECOND;
              break;
          case Calendar.MILLISECOND:
              result = 1;
              break;
          default: throw new IllegalArgumentException("The unit " + unit + " cannot be represented is milleseconds");
      }
      return result;
  }
}





Returns true if endDate is after startDate or if startDate equals endDate.

  
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  The ASF licenses this file to You
 * under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.  For additional information regarding
 * copyright in this work, please see the NOTICE file in the top level
 * directory of this distribution.
 */
import java.util.Date;
public class Utils {
  /**
   * Returns true if endDate is after startDate or if startDate equals endDate.
   * Returns false if either value is null.  If equalOK, returns true if the
   * dates are equal.
   **/
  public static boolean isValidDateRange(Date startDate, Date endDate, boolean equalOK) {
      // false if either value is null
      if (startDate == null || endDate == null) { return false; }
      
      if (equalOK) {
          // true if they are equal
          if (startDate.equals(endDate)) { return true; }
      }
      
      // true if endDate after startDate
      if (endDate.after(startDate)) { return true; }
      
      return false;
  }
}





Roll the days forward or backward

   
/*
 * Copyright Javelin Software, All rights reserved.
 */

import java.util.*;
import java.text.*;
/**
 * The DateUtil is used as a Utility Class for Dates.
 * 
 * @author Robin Sharp
 */
public class DateUtil 
{
    public final static long SECOND_MILLIS = 1000;
    public final static long MINUTE_MILLIS = SECOND_MILLIS*60;
    public final static long HOUR_MILLIS = MINUTE_MILLIS*60;
    public final static long DAY_MILLIS = HOUR_MILLIS*24;
    public final static long YEAR_MILLIS = DAY_MILLIS*365;
    public static DateFormat OUT_DATE_FORMAT = new SimpleDateFormat("dd/MM/yyyy");
    public static DateFormat OUT_TIME_FORMAT = new SimpleDateFormat("H:mm:ss");
    public static DateFormat OUT_DATETIME_FORMAT = new SimpleDateFormat("d/M/yyyy H:mm:ss");
    public static DateFormat OUT_TIMESTAMP_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss.SSS");
    
    public static DateFormat IN_DATE_FORMAT = new SimpleDateFormat("d/M/yy");
    public static DateFormat IN_TIME_FORMAT = new SimpleDateFormat("H:mm:ss");
    public static DateFormat IN_DATETIME_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss");
    public static DateFormat IN_TIMESTAMP_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss.SSS");
    
    public static DateFormat DATE_TIME_FORMAT= new SimpleDateFormat( "yyyyMMddkkmmss" );  
    public static Calendar calendar = new GregorianCalendar();
    static
    {
        IN_DATE_FORMAT.setLenient(false);
        IN_TIME_FORMAT.setLenient(false);
        IN_DATETIME_FORMAT.setLenient(false);
    }
    /**
     * Create a new DateTime. To the last second. This will not create any 
     * extra-millis-seconds, which may cause bugs when writing to stores such as
     * databases that round milli-seconds up and down. 
     */
    public static java.util.Date newDateTime()
    {
        return new java.util.Date( (System.currentTimeMillis()/SECOND_MILLIS)*SECOND_MILLIS);
    }
    /**
     * Create a new Date. To the last day.
     */
    public static java.sql.Date newDate()
    {
        return new java.sql.Date( (System.currentTimeMillis()/DAY_MILLIS)*DAY_MILLIS);
    }
    
    /**
     * Create a new Time, with no date component. 
     */
    public static java.sql.Time newTime()
    {
        return new java.sql.Time( System.currentTimeMillis()%DAY_MILLIS);
    }
    
    /**
     * Create a new Timestamp. 
     */
    public static java.sql.Timestamp newTimestamp()
    {
        return new java.sql.Timestamp( System.currentTimeMillis() );
    }
    
    /**
     * Get the seconds difference
     */
    public static int secondsDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/SECOND_MILLIS) - (earlierDate.getTime()/SECOND_MILLIS));
    }
    /**
     * Get the minutes difference
     */
    public static int minutesDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/MINUTE_MILLIS) - (earlierDate.getTime()/MINUTE_MILLIS));
    }
    
    /**
     * Get the hours difference
     */
    public static int hoursDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/HOUR_MILLIS) - (earlierDate.getTime()/HOUR_MILLIS));
    }
    
    /**
     * Get the days difference
     */
    public static int daysDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/DAY_MILLIS) - (earlierDate.getTime()/DAY_MILLIS));
    }
    
   /**
    * Roll the java.util.Time forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.sql.Time rollTime( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.sql.Time(gc.getTime().getTime());
    }
    
   /**
    * Roll the java.util.Date forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.util.Date rollDateTime( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.util.Date(gc.getTime().getTime());
    }
    
   /**
    * Roll the java.sql.Date forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.sql.Date rollDate( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.sql.Date(gc.getTime().getTime());
    }
    
   /**
    * Roll the years forward or backward.
    * @param startDate - The start date
    * @param years - Negative to rollbackwards.
    */
    public static java.sql.Date rollYears( java.util.Date startDate, int years )
    {
        return rollDate( startDate, Calendar.YEAR, years );
    }
   /**
    * Roll the days forward or backward.
    * @param startDate - The start date
    * @param months - Negative to rollbackwards.
    */
    public static java.sql.Date rollMonths( java.util.Date startDate, int months )
    {
        return rollDate( startDate, Calendar.MONTH, months );
    }
   /**
    * Roll the days forward or backward.
    * @param startDate - The start date
    * @param days - Negative to rollbackwards.
    */
    public static java.sql.Date rollDays( java.util.Date startDate, int days )
    {
        return rollDate( startDate, Calendar.DATE, days );
    }
    
     /**
      * Checks the day, month and year are equal.
      */
     public static boolean dateEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;
        
        return d1.getDate() == d2.getDate() &&
               d1.getMonth() == d2.getMonth() &&
               d1.getYear() == d2.getYear();
     }
     
     /**
      * Checks the hour, minute and second are equal.
      */
     public static boolean timeEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;
        
        return d1.getHours() == d2.getHours() &&
               d1.getMinutes() == d2.getMinutes() &&
               d1.getSeconds() == d2.getSeconds();
     }

    /**
      * Checks the second, hour, month, day, month and year are equal.
      */
     public static boolean dateTimeEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;               
        
        return d1.getDate() == d2.getDate() &&
               d1.getMonth() == d2.getMonth() &&
               d1.getYear() == d2.getYear() &&
               d1.getHours() == d2.getHours() &&
               d1.getMinutes() == d2.getMinutes() &&
               d1.getSeconds() == d2.getSeconds();
     }
     
     /**
     * Convert an Object of type Classs to an Object.
     */
    public static Object toObject( Class clazz, Object value ) throws ParseException
    {
        if( value == null ) return null;
        if( clazz == null ) return value;
        
        if( java.sql.Date.class.isAssignableFrom( clazz ) ) return toDate( value );
        if( java.sql.Time.class.isAssignableFrom( clazz ) ) return toTime( value );
        if( java.sql.Timestamp.class.isAssignableFrom( clazz ) ) return toTimestamp( value );
        if( java.util.Date.class.isAssignableFrom( clazz ) ) return toDateTime( value );
        
        return value;
    }
    
    /**
     * Convert an Object to a DateTime, without an Exception
     */
    public static java.util.Date getDateTime( Object value )
    {
        try
        {
            return toDateTime( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    
    /**
     * Convert an Object to a DateTime.
     */
    public static java.util.Date toDateTime( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.util.Date ) return (java.util.Date)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return IN_DATETIME_FORMAT.parse( (String)value );
        }
                
        return IN_DATETIME_FORMAT.parse( value.toString() );
    }
    
    /**
     * Convert an Object to a Date, without an Exception
     */
    public static java.sql.Date getDate( Object value )
    {
        try
        {
            return toDate( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    /**
     * Convert an Object to a Date.
     */
    public static java.sql.Date toDate( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Date ) return (java.sql.Date)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Date( IN_DATE_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Date( IN_DATE_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Convert an Object to a Time, without an Exception
     */
    public static java.sql.Time getTime( Object value )
    {
        try
        {
            return toTime( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    
    /**
     * Convert an Object to a Time.
     */
    public static java.sql.Time toTime( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Time ) return (java.sql.Time)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Time( IN_TIME_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Time( IN_TIME_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Convert an Object to a Timestamp, without an Exception
     */
    public static java.sql.Timestamp getTimestamp( Object value )
    {
        try
        {
            return toTimestamp( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    /**
     * Convert an Object to a Timestamp.
     */
    public static java.sql.Timestamp toTimestamp( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Timestamp ) return (java.sql.Timestamp)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Timestamp( IN_TIMESTAMP_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Timestamp( IN_TIMESTAMP_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Tells you if the date part of a datetime is in a certain time range.
     */
    public static boolean isTimeInRange( java.sql.Time start, java.sql.Time end, java.util.Date d )
    {
        d=new java.sql.Time(d.getHours(),d.getMinutes(),d.getSeconds());
        
        if (start==null || end==null)
        {
            return false;
        }
        
        if (start.before(end)&&(!(d.after(start)&&d.before(end))))
        {
            return false;
        }
        
        if (end.before(start)&&(!(d.after(end)||d.before(start))))
        {
            return false;
        }   
        return true;
    }
    public static  int getYear( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.YEAR );
    }
    public static int getMonth( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MONTH );
    }
    public static int getDate( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.DATE );
    }
    public static int getHour( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.HOUR );
    }
    public static int getMinute( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MINUTE );
    }
    public static int getSeconds( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.SECOND );
    }
    public static int getMillisecond( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MILLISECOND );
    }
    
    /**
     * Convert an Object to a String using Dates
     */
    public static String toString( Object date )
    {
        if( date == null ) return null;
        
        if( java.sql.Timestamp.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_TIMESTAMP_FORMAT.format( date );
        }
        if( java.sql.Time.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_TIME_FORMAT.format( date );
        }
        if( java.sql.Date.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_DATE_FORMAT.format( date );
        }
        if( java.util.Date.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_DATETIME_FORMAT.format( date );
        }
        
        throw new IllegalArgumentException( "Unsupported type " + date.getClass() );
    }
}





Roll the java.sql.Date forward or backward

   
/*
 * Copyright Javelin Software, All rights reserved.
 */

import java.util.*;
import java.text.*;
/**
 * The DateUtil is used as a Utility Class for Dates.
 * 
 * @author Robin Sharp
 */
public class DateUtil 
{
    public final static long SECOND_MILLIS = 1000;
    public final static long MINUTE_MILLIS = SECOND_MILLIS*60;
    public final static long HOUR_MILLIS = MINUTE_MILLIS*60;
    public final static long DAY_MILLIS = HOUR_MILLIS*24;
    public final static long YEAR_MILLIS = DAY_MILLIS*365;
    public static DateFormat OUT_DATE_FORMAT = new SimpleDateFormat("dd/MM/yyyy");
    public static DateFormat OUT_TIME_FORMAT = new SimpleDateFormat("H:mm:ss");
    public static DateFormat OUT_DATETIME_FORMAT = new SimpleDateFormat("d/M/yyyy H:mm:ss");
    public static DateFormat OUT_TIMESTAMP_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss.SSS");
    
    public static DateFormat IN_DATE_FORMAT = new SimpleDateFormat("d/M/yy");
    public static DateFormat IN_TIME_FORMAT = new SimpleDateFormat("H:mm:ss");
    public static DateFormat IN_DATETIME_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss");
    public static DateFormat IN_TIMESTAMP_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss.SSS");
    
    public static DateFormat DATE_TIME_FORMAT= new SimpleDateFormat( "yyyyMMddkkmmss" );  
    public static Calendar calendar = new GregorianCalendar();
    static
    {
        IN_DATE_FORMAT.setLenient(false);
        IN_TIME_FORMAT.setLenient(false);
        IN_DATETIME_FORMAT.setLenient(false);
    }
    /**
     * Create a new DateTime. To the last second. This will not create any 
     * extra-millis-seconds, which may cause bugs when writing to stores such as
     * databases that round milli-seconds up and down. 
     */
    public static java.util.Date newDateTime()
    {
        return new java.util.Date( (System.currentTimeMillis()/SECOND_MILLIS)*SECOND_MILLIS);
    }
    /**
     * Create a new Date. To the last day.
     */
    public static java.sql.Date newDate()
    {
        return new java.sql.Date( (System.currentTimeMillis()/DAY_MILLIS)*DAY_MILLIS);
    }
    
    /**
     * Create a new Time, with no date component. 
     */
    public static java.sql.Time newTime()
    {
        return new java.sql.Time( System.currentTimeMillis()%DAY_MILLIS);
    }
    
    /**
     * Create a new Timestamp. 
     */
    public static java.sql.Timestamp newTimestamp()
    {
        return new java.sql.Timestamp( System.currentTimeMillis() );
    }
    
    /**
     * Get the seconds difference
     */
    public static int secondsDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/SECOND_MILLIS) - (earlierDate.getTime()/SECOND_MILLIS));
    }
    /**
     * Get the minutes difference
     */
    public static int minutesDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/MINUTE_MILLIS) - (earlierDate.getTime()/MINUTE_MILLIS));
    }
    
    /**
     * Get the hours difference
     */
    public static int hoursDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/HOUR_MILLIS) - (earlierDate.getTime()/HOUR_MILLIS));
    }
    
    /**
     * Get the days difference
     */
    public static int daysDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/DAY_MILLIS) - (earlierDate.getTime()/DAY_MILLIS));
    }
    
   /**
    * Roll the java.util.Time forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.sql.Time rollTime( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.sql.Time(gc.getTime().getTime());
    }
    
   /**
    * Roll the java.util.Date forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.util.Date rollDateTime( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.util.Date(gc.getTime().getTime());
    }
    
   /**
    * Roll the java.sql.Date forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.sql.Date rollDate( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.sql.Date(gc.getTime().getTime());
    }
    
   /**
    * Roll the years forward or backward.
    * @param startDate - The start date
    * @param years - Negative to rollbackwards.
    */
    public static java.sql.Date rollYears( java.util.Date startDate, int years )
    {
        return rollDate( startDate, Calendar.YEAR, years );
    }
   /**
    * Roll the days forward or backward.
    * @param startDate - The start date
    * @param months - Negative to rollbackwards.
    */
    public static java.sql.Date rollMonths( java.util.Date startDate, int months )
    {
        return rollDate( startDate, Calendar.MONTH, months );
    }
   /**
    * Roll the days forward or backward.
    * @param startDate - The start date
    * @param days - Negative to rollbackwards.
    */
    public static java.sql.Date rollDays( java.util.Date startDate, int days )
    {
        return rollDate( startDate, Calendar.DATE, days );
    }
    
     /**
      * Checks the day, month and year are equal.
      */
     public static boolean dateEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;
        
        return d1.getDate() == d2.getDate() &&
               d1.getMonth() == d2.getMonth() &&
               d1.getYear() == d2.getYear();
     }
     
     /**
      * Checks the hour, minute and second are equal.
      */
     public static boolean timeEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;
        
        return d1.getHours() == d2.getHours() &&
               d1.getMinutes() == d2.getMinutes() &&
               d1.getSeconds() == d2.getSeconds();
     }

    /**
      * Checks the second, hour, month, day, month and year are equal.
      */
     public static boolean dateTimeEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;               
        
        return d1.getDate() == d2.getDate() &&
               d1.getMonth() == d2.getMonth() &&
               d1.getYear() == d2.getYear() &&
               d1.getHours() == d2.getHours() &&
               d1.getMinutes() == d2.getMinutes() &&
               d1.getSeconds() == d2.getSeconds();
     }
     
     /**
     * Convert an Object of type Classs to an Object.
     */
    public static Object toObject( Class clazz, Object value ) throws ParseException
    {
        if( value == null ) return null;
        if( clazz == null ) return value;
        
        if( java.sql.Date.class.isAssignableFrom( clazz ) ) return toDate( value );
        if( java.sql.Time.class.isAssignableFrom( clazz ) ) return toTime( value );
        if( java.sql.Timestamp.class.isAssignableFrom( clazz ) ) return toTimestamp( value );
        if( java.util.Date.class.isAssignableFrom( clazz ) ) return toDateTime( value );
        
        return value;
    }
    
    /**
     * Convert an Object to a DateTime, without an Exception
     */
    public static java.util.Date getDateTime( Object value )
    {
        try
        {
            return toDateTime( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    
    /**
     * Convert an Object to a DateTime.
     */
    public static java.util.Date toDateTime( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.util.Date ) return (java.util.Date)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return IN_DATETIME_FORMAT.parse( (String)value );
        }
                
        return IN_DATETIME_FORMAT.parse( value.toString() );
    }
    
    /**
     * Convert an Object to a Date, without an Exception
     */
    public static java.sql.Date getDate( Object value )
    {
        try
        {
            return toDate( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    /**
     * Convert an Object to a Date.
     */
    public static java.sql.Date toDate( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Date ) return (java.sql.Date)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Date( IN_DATE_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Date( IN_DATE_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Convert an Object to a Time, without an Exception
     */
    public static java.sql.Time getTime( Object value )
    {
        try
        {
            return toTime( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    
    /**
     * Convert an Object to a Time.
     */
    public static java.sql.Time toTime( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Time ) return (java.sql.Time)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Time( IN_TIME_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Time( IN_TIME_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Convert an Object to a Timestamp, without an Exception
     */
    public static java.sql.Timestamp getTimestamp( Object value )
    {
        try
        {
            return toTimestamp( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    /**
     * Convert an Object to a Timestamp.
     */
    public static java.sql.Timestamp toTimestamp( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Timestamp ) return (java.sql.Timestamp)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Timestamp( IN_TIMESTAMP_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Timestamp( IN_TIMESTAMP_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Tells you if the date part of a datetime is in a certain time range.
     */
    public static boolean isTimeInRange( java.sql.Time start, java.sql.Time end, java.util.Date d )
    {
        d=new java.sql.Time(d.getHours(),d.getMinutes(),d.getSeconds());
        
        if (start==null || end==null)
        {
            return false;
        }
        
        if (start.before(end)&&(!(d.after(start)&&d.before(end))))
        {
            return false;
        }
        
        if (end.before(start)&&(!(d.after(end)||d.before(start))))
        {
            return false;
        }   
        return true;
    }
    public static  int getYear( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.YEAR );
    }
    public static int getMonth( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MONTH );
    }
    public static int getDate( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.DATE );
    }
    public static int getHour( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.HOUR );
    }
    public static int getMinute( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MINUTE );
    }
    public static int getSeconds( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.SECOND );
    }
    public static int getMillisecond( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MILLISECOND );
    }
    
    /**
     * Convert an Object to a String using Dates
     */
    public static String toString( Object date )
    {
        if( date == null ) return null;
        
        if( java.sql.Timestamp.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_TIMESTAMP_FORMAT.format( date );
        }
        if( java.sql.Time.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_TIME_FORMAT.format( date );
        }
        if( java.sql.Date.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_DATE_FORMAT.format( date );
        }
        if( java.util.Date.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_DATETIME_FORMAT.format( date );
        }
        
        throw new IllegalArgumentException( "Unsupported type " + date.getClass() );
    }
}





Roll the java.util.Date forward or backward

   
/*
 * Copyright Javelin Software, All rights reserved.
 */

import java.util.*;
import java.text.*;
/**
 * The DateUtil is used as a Utility Class for Dates.
 * 
 * @author Robin Sharp
 */
public class DateUtil 
{
    public final static long SECOND_MILLIS = 1000;
    public final static long MINUTE_MILLIS = SECOND_MILLIS*60;
    public final static long HOUR_MILLIS = MINUTE_MILLIS*60;
    public final static long DAY_MILLIS = HOUR_MILLIS*24;
    public final static long YEAR_MILLIS = DAY_MILLIS*365;
    public static DateFormat OUT_DATE_FORMAT = new SimpleDateFormat("dd/MM/yyyy");
    public static DateFormat OUT_TIME_FORMAT = new SimpleDateFormat("H:mm:ss");
    public static DateFormat OUT_DATETIME_FORMAT = new SimpleDateFormat("d/M/yyyy H:mm:ss");
    public static DateFormat OUT_TIMESTAMP_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss.SSS");
    
    public static DateFormat IN_DATE_FORMAT = new SimpleDateFormat("d/M/yy");
    public static DateFormat IN_TIME_FORMAT = new SimpleDateFormat("H:mm:ss");
    public static DateFormat IN_DATETIME_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss");
    public static DateFormat IN_TIMESTAMP_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss.SSS");
    
    public static DateFormat DATE_TIME_FORMAT= new SimpleDateFormat( "yyyyMMddkkmmss" );  
    public static Calendar calendar = new GregorianCalendar();
    static
    {
        IN_DATE_FORMAT.setLenient(false);
        IN_TIME_FORMAT.setLenient(false);
        IN_DATETIME_FORMAT.setLenient(false);
    }
    /**
     * Create a new DateTime. To the last second. This will not create any 
     * extra-millis-seconds, which may cause bugs when writing to stores such as
     * databases that round milli-seconds up and down. 
     */
    public static java.util.Date newDateTime()
    {
        return new java.util.Date( (System.currentTimeMillis()/SECOND_MILLIS)*SECOND_MILLIS);
    }
    /**
     * Create a new Date. To the last day.
     */
    public static java.sql.Date newDate()
    {
        return new java.sql.Date( (System.currentTimeMillis()/DAY_MILLIS)*DAY_MILLIS);
    }
    
    /**
     * Create a new Time, with no date component. 
     */
    public static java.sql.Time newTime()
    {
        return new java.sql.Time( System.currentTimeMillis()%DAY_MILLIS);
    }
    
    /**
     * Create a new Timestamp. 
     */
    public static java.sql.Timestamp newTimestamp()
    {
        return new java.sql.Timestamp( System.currentTimeMillis() );
    }
    
    /**
     * Get the seconds difference
     */
    public static int secondsDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/SECOND_MILLIS) - (earlierDate.getTime()/SECOND_MILLIS));
    }
    /**
     * Get the minutes difference
     */
    public static int minutesDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/MINUTE_MILLIS) - (earlierDate.getTime()/MINUTE_MILLIS));
    }
    
    /**
     * Get the hours difference
     */
    public static int hoursDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/HOUR_MILLIS) - (earlierDate.getTime()/HOUR_MILLIS));
    }
    
    /**
     * Get the days difference
     */
    public static int daysDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/DAY_MILLIS) - (earlierDate.getTime()/DAY_MILLIS));
    }
    
   /**
    * Roll the java.util.Time forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.sql.Time rollTime( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.sql.Time(gc.getTime().getTime());
    }
    
   /**
    * Roll the java.util.Date forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.util.Date rollDateTime( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.util.Date(gc.getTime().getTime());
    }
    
   /**
    * Roll the java.sql.Date forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.sql.Date rollDate( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.sql.Date(gc.getTime().getTime());
    }
    
   /**
    * Roll the years forward or backward.
    * @param startDate - The start date
    * @param years - Negative to rollbackwards.
    */
    public static java.sql.Date rollYears( java.util.Date startDate, int years )
    {
        return rollDate( startDate, Calendar.YEAR, years );
    }
   /**
    * Roll the days forward or backward.
    * @param startDate - The start date
    * @param months - Negative to rollbackwards.
    */
    public static java.sql.Date rollMonths( java.util.Date startDate, int months )
    {
        return rollDate( startDate, Calendar.MONTH, months );
    }
   /**
    * Roll the days forward or backward.
    * @param startDate - The start date
    * @param days - Negative to rollbackwards.
    */
    public static java.sql.Date rollDays( java.util.Date startDate, int days )
    {
        return rollDate( startDate, Calendar.DATE, days );
    }
    
     /**
      * Checks the day, month and year are equal.
      */
     public static boolean dateEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;
        
        return d1.getDate() == d2.getDate() &&
               d1.getMonth() == d2.getMonth() &&
               d1.getYear() == d2.getYear();
     }
     
     /**
      * Checks the hour, minute and second are equal.
      */
     public static boolean timeEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;
        
        return d1.getHours() == d2.getHours() &&
               d1.getMinutes() == d2.getMinutes() &&
               d1.getSeconds() == d2.getSeconds();
     }

    /**
      * Checks the second, hour, month, day, month and year are equal.
      */
     public static boolean dateTimeEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;               
        
        return d1.getDate() == d2.getDate() &&
               d1.getMonth() == d2.getMonth() &&
               d1.getYear() == d2.getYear() &&
               d1.getHours() == d2.getHours() &&
               d1.getMinutes() == d2.getMinutes() &&
               d1.getSeconds() == d2.getSeconds();
     }
     
     /**
     * Convert an Object of type Classs to an Object.
     */
    public static Object toObject( Class clazz, Object value ) throws ParseException
    {
        if( value == null ) return null;
        if( clazz == null ) return value;
        
        if( java.sql.Date.class.isAssignableFrom( clazz ) ) return toDate( value );
        if( java.sql.Time.class.isAssignableFrom( clazz ) ) return toTime( value );
        if( java.sql.Timestamp.class.isAssignableFrom( clazz ) ) return toTimestamp( value );
        if( java.util.Date.class.isAssignableFrom( clazz ) ) return toDateTime( value );
        
        return value;
    }
    
    /**
     * Convert an Object to a DateTime, without an Exception
     */
    public static java.util.Date getDateTime( Object value )
    {
        try
        {
            return toDateTime( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    
    /**
     * Convert an Object to a DateTime.
     */
    public static java.util.Date toDateTime( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.util.Date ) return (java.util.Date)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return IN_DATETIME_FORMAT.parse( (String)value );
        }
                
        return IN_DATETIME_FORMAT.parse( value.toString() );
    }
    
    /**
     * Convert an Object to a Date, without an Exception
     */
    public static java.sql.Date getDate( Object value )
    {
        try
        {
            return toDate( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    /**
     * Convert an Object to a Date.
     */
    public static java.sql.Date toDate( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Date ) return (java.sql.Date)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Date( IN_DATE_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Date( IN_DATE_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Convert an Object to a Time, without an Exception
     */
    public static java.sql.Time getTime( Object value )
    {
        try
        {
            return toTime( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    
    /**
     * Convert an Object to a Time.
     */
    public static java.sql.Time toTime( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Time ) return (java.sql.Time)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Time( IN_TIME_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Time( IN_TIME_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Convert an Object to a Timestamp, without an Exception
     */
    public static java.sql.Timestamp getTimestamp( Object value )
    {
        try
        {
            return toTimestamp( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    /**
     * Convert an Object to a Timestamp.
     */
    public static java.sql.Timestamp toTimestamp( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Timestamp ) return (java.sql.Timestamp)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Timestamp( IN_TIMESTAMP_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Timestamp( IN_TIMESTAMP_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Tells you if the date part of a datetime is in a certain time range.
     */
    public static boolean isTimeInRange( java.sql.Time start, java.sql.Time end, java.util.Date d )
    {
        d=new java.sql.Time(d.getHours(),d.getMinutes(),d.getSeconds());
        
        if (start==null || end==null)
        {
            return false;
        }
        
        if (start.before(end)&&(!(d.after(start)&&d.before(end))))
        {
            return false;
        }
        
        if (end.before(start)&&(!(d.after(end)||d.before(start))))
        {
            return false;
        }   
        return true;
    }
    public static  int getYear( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.YEAR );
    }
    public static int getMonth( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MONTH );
    }
    public static int getDate( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.DATE );
    }
    public static int getHour( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.HOUR );
    }
    public static int getMinute( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MINUTE );
    }
    public static int getSeconds( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.SECOND );
    }
    public static int getMillisecond( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MILLISECOND );
    }
    
    /**
     * Convert an Object to a String using Dates
     */
    public static String toString( Object date )
    {
        if( date == null ) return null;
        
        if( java.sql.Timestamp.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_TIMESTAMP_FORMAT.format( date );
        }
        if( java.sql.Time.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_TIME_FORMAT.format( date );
        }
        if( java.sql.Date.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_DATE_FORMAT.format( date );
        }
        if( java.util.Date.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_DATETIME_FORMAT.format( date );
        }
        
        throw new IllegalArgumentException( "Unsupported type " + date.getClass() );
    }
}





Roll the java.util.Time forward or backward

   
/*
 * Copyright Javelin Software, All rights reserved.
 */

import java.util.*;
import java.text.*;
/**
 * The DateUtil is used as a Utility Class for Dates.
 * 
 * @author Robin Sharp
 */
public class DateUtil 
{
    public final static long SECOND_MILLIS = 1000;
    public final static long MINUTE_MILLIS = SECOND_MILLIS*60;
    public final static long HOUR_MILLIS = MINUTE_MILLIS*60;
    public final static long DAY_MILLIS = HOUR_MILLIS*24;
    public final static long YEAR_MILLIS = DAY_MILLIS*365;
    public static DateFormat OUT_DATE_FORMAT = new SimpleDateFormat("dd/MM/yyyy");
    public static DateFormat OUT_TIME_FORMAT = new SimpleDateFormat("H:mm:ss");
    public static DateFormat OUT_DATETIME_FORMAT = new SimpleDateFormat("d/M/yyyy H:mm:ss");
    public static DateFormat OUT_TIMESTAMP_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss.SSS");
    
    public static DateFormat IN_DATE_FORMAT = new SimpleDateFormat("d/M/yy");
    public static DateFormat IN_TIME_FORMAT = new SimpleDateFormat("H:mm:ss");
    public static DateFormat IN_DATETIME_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss");
    public static DateFormat IN_TIMESTAMP_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss.SSS");
    
    public static DateFormat DATE_TIME_FORMAT= new SimpleDateFormat( "yyyyMMddkkmmss" );  
    public static Calendar calendar = new GregorianCalendar();
    static
    {
        IN_DATE_FORMAT.setLenient(false);
        IN_TIME_FORMAT.setLenient(false);
        IN_DATETIME_FORMAT.setLenient(false);
    }
    /**
     * Create a new DateTime. To the last second. This will not create any 
     * extra-millis-seconds, which may cause bugs when writing to stores such as
     * databases that round milli-seconds up and down. 
     */
    public static java.util.Date newDateTime()
    {
        return new java.util.Date( (System.currentTimeMillis()/SECOND_MILLIS)*SECOND_MILLIS);
    }
    /**
     * Create a new Date. To the last day.
     */
    public static java.sql.Date newDate()
    {
        return new java.sql.Date( (System.currentTimeMillis()/DAY_MILLIS)*DAY_MILLIS);
    }
    
    /**
     * Create a new Time, with no date component. 
     */
    public static java.sql.Time newTime()
    {
        return new java.sql.Time( System.currentTimeMillis()%DAY_MILLIS);
    }
    
    /**
     * Create a new Timestamp. 
     */
    public static java.sql.Timestamp newTimestamp()
    {
        return new java.sql.Timestamp( System.currentTimeMillis() );
    }
    
    /**
     * Get the seconds difference
     */
    public static int secondsDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/SECOND_MILLIS) - (earlierDate.getTime()/SECOND_MILLIS));
    }
    /**
     * Get the minutes difference
     */
    public static int minutesDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/MINUTE_MILLIS) - (earlierDate.getTime()/MINUTE_MILLIS));
    }
    
    /**
     * Get the hours difference
     */
    public static int hoursDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/HOUR_MILLIS) - (earlierDate.getTime()/HOUR_MILLIS));
    }
    
    /**
     * Get the days difference
     */
    public static int daysDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/DAY_MILLIS) - (earlierDate.getTime()/DAY_MILLIS));
    }
    
   /**
    * Roll the java.util.Time forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.sql.Time rollTime( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.sql.Time(gc.getTime().getTime());
    }
    
   /**
    * Roll the java.util.Date forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.util.Date rollDateTime( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.util.Date(gc.getTime().getTime());
    }
    
   /**
    * Roll the java.sql.Date forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.sql.Date rollDate( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.sql.Date(gc.getTime().getTime());
    }
    
   /**
    * Roll the years forward or backward.
    * @param startDate - The start date
    * @param years - Negative to rollbackwards.
    */
    public static java.sql.Date rollYears( java.util.Date startDate, int years )
    {
        return rollDate( startDate, Calendar.YEAR, years );
    }
   /**
    * Roll the days forward or backward.
    * @param startDate - The start date
    * @param months - Negative to rollbackwards.
    */
    public static java.sql.Date rollMonths( java.util.Date startDate, int months )
    {
        return rollDate( startDate, Calendar.MONTH, months );
    }
   /**
    * Roll the days forward or backward.
    * @param startDate - The start date
    * @param days - Negative to rollbackwards.
    */
    public static java.sql.Date rollDays( java.util.Date startDate, int days )
    {
        return rollDate( startDate, Calendar.DATE, days );
    }
    
     /**
      * Checks the day, month and year are equal.
      */
     public static boolean dateEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;
        
        return d1.getDate() == d2.getDate() &&
               d1.getMonth() == d2.getMonth() &&
               d1.getYear() == d2.getYear();
     }
     
     /**
      * Checks the hour, minute and second are equal.
      */
     public static boolean timeEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;
        
        return d1.getHours() == d2.getHours() &&
               d1.getMinutes() == d2.getMinutes() &&
               d1.getSeconds() == d2.getSeconds();
     }

    /**
      * Checks the second, hour, month, day, month and year are equal.
      */
     public static boolean dateTimeEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;               
        
        return d1.getDate() == d2.getDate() &&
               d1.getMonth() == d2.getMonth() &&
               d1.getYear() == d2.getYear() &&
               d1.getHours() == d2.getHours() &&
               d1.getMinutes() == d2.getMinutes() &&
               d1.getSeconds() == d2.getSeconds();
     }
     
     /**
     * Convert an Object of type Classs to an Object.
     */
    public static Object toObject( Class clazz, Object value ) throws ParseException
    {
        if( value == null ) return null;
        if( clazz == null ) return value;
        
        if( java.sql.Date.class.isAssignableFrom( clazz ) ) return toDate( value );
        if( java.sql.Time.class.isAssignableFrom( clazz ) ) return toTime( value );
        if( java.sql.Timestamp.class.isAssignableFrom( clazz ) ) return toTimestamp( value );
        if( java.util.Date.class.isAssignableFrom( clazz ) ) return toDateTime( value );
        
        return value;
    }
    
    /**
     * Convert an Object to a DateTime, without an Exception
     */
    public static java.util.Date getDateTime( Object value )
    {
        try
        {
            return toDateTime( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    
    /**
     * Convert an Object to a DateTime.
     */
    public static java.util.Date toDateTime( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.util.Date ) return (java.util.Date)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return IN_DATETIME_FORMAT.parse( (String)value );
        }
                
        return IN_DATETIME_FORMAT.parse( value.toString() );
    }
    
    /**
     * Convert an Object to a Date, without an Exception
     */
    public static java.sql.Date getDate( Object value )
    {
        try
        {
            return toDate( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    /**
     * Convert an Object to a Date.
     */
    public static java.sql.Date toDate( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Date ) return (java.sql.Date)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Date( IN_DATE_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Date( IN_DATE_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Convert an Object to a Time, without an Exception
     */
    public static java.sql.Time getTime( Object value )
    {
        try
        {
            return toTime( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    
    /**
     * Convert an Object to a Time.
     */
    public static java.sql.Time toTime( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Time ) return (java.sql.Time)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Time( IN_TIME_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Time( IN_TIME_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Convert an Object to a Timestamp, without an Exception
     */
    public static java.sql.Timestamp getTimestamp( Object value )
    {
        try
        {
            return toTimestamp( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    /**
     * Convert an Object to a Timestamp.
     */
    public static java.sql.Timestamp toTimestamp( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Timestamp ) return (java.sql.Timestamp)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Timestamp( IN_TIMESTAMP_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Timestamp( IN_TIMESTAMP_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Tells you if the date part of a datetime is in a certain time range.
     */
    public static boolean isTimeInRange( java.sql.Time start, java.sql.Time end, java.util.Date d )
    {
        d=new java.sql.Time(d.getHours(),d.getMinutes(),d.getSeconds());
        
        if (start==null || end==null)
        {
            return false;
        }
        
        if (start.before(end)&&(!(d.after(start)&&d.before(end))))
        {
            return false;
        }
        
        if (end.before(start)&&(!(d.after(end)||d.before(start))))
        {
            return false;
        }   
        return true;
    }
    public static  int getYear( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.YEAR );
    }
    public static int getMonth( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MONTH );
    }
    public static int getDate( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.DATE );
    }
    public static int getHour( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.HOUR );
    }
    public static int getMinute( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MINUTE );
    }
    public static int getSeconds( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.SECOND );
    }
    public static int getMillisecond( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MILLISECOND );
    }
    
    /**
     * Convert an Object to a String using Dates
     */
    public static String toString( Object date )
    {
        if( date == null ) return null;
        
        if( java.sql.Timestamp.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_TIMESTAMP_FORMAT.format( date );
        }
        if( java.sql.Time.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_TIME_FORMAT.format( date );
        }
        if( java.sql.Date.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_DATE_FORMAT.format( date );
        }
        if( java.util.Date.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_DATETIME_FORMAT.format( date );
        }
        
        throw new IllegalArgumentException( "Unsupported type " + date.getClass() );
    }
}





Roll the years forward or backward

   
/*
 * Copyright Javelin Software, All rights reserved.
 */

import java.util.*;
import java.text.*;
/**
 * The DateUtil is used as a Utility Class for Dates.
 * 
 * @author Robin Sharp
 */
public class DateUtil 
{
    public final static long SECOND_MILLIS = 1000;
    public final static long MINUTE_MILLIS = SECOND_MILLIS*60;
    public final static long HOUR_MILLIS = MINUTE_MILLIS*60;
    public final static long DAY_MILLIS = HOUR_MILLIS*24;
    public final static long YEAR_MILLIS = DAY_MILLIS*365;
    public static DateFormat OUT_DATE_FORMAT = new SimpleDateFormat("dd/MM/yyyy");
    public static DateFormat OUT_TIME_FORMAT = new SimpleDateFormat("H:mm:ss");
    public static DateFormat OUT_DATETIME_FORMAT = new SimpleDateFormat("d/M/yyyy H:mm:ss");
    public static DateFormat OUT_TIMESTAMP_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss.SSS");
    
    public static DateFormat IN_DATE_FORMAT = new SimpleDateFormat("d/M/yy");
    public static DateFormat IN_TIME_FORMAT = new SimpleDateFormat("H:mm:ss");
    public static DateFormat IN_DATETIME_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss");
    public static DateFormat IN_TIMESTAMP_FORMAT = new SimpleDateFormat("d/M/yy H:mm:ss.SSS");
    
    public static DateFormat DATE_TIME_FORMAT= new SimpleDateFormat( "yyyyMMddkkmmss" );  
    public static Calendar calendar = new GregorianCalendar();
    static
    {
        IN_DATE_FORMAT.setLenient(false);
        IN_TIME_FORMAT.setLenient(false);
        IN_DATETIME_FORMAT.setLenient(false);
    }
    /**
     * Create a new DateTime. To the last second. This will not create any 
     * extra-millis-seconds, which may cause bugs when writing to stores such as
     * databases that round milli-seconds up and down. 
     */
    public static java.util.Date newDateTime()
    {
        return new java.util.Date( (System.currentTimeMillis()/SECOND_MILLIS)*SECOND_MILLIS);
    }
    /**
     * Create a new Date. To the last day.
     */
    public static java.sql.Date newDate()
    {
        return new java.sql.Date( (System.currentTimeMillis()/DAY_MILLIS)*DAY_MILLIS);
    }
    
    /**
     * Create a new Time, with no date component. 
     */
    public static java.sql.Time newTime()
    {
        return new java.sql.Time( System.currentTimeMillis()%DAY_MILLIS);
    }
    
    /**
     * Create a new Timestamp. 
     */
    public static java.sql.Timestamp newTimestamp()
    {
        return new java.sql.Timestamp( System.currentTimeMillis() );
    }
    
    /**
     * Get the seconds difference
     */
    public static int secondsDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/SECOND_MILLIS) - (earlierDate.getTime()/SECOND_MILLIS));
    }
    /**
     * Get the minutes difference
     */
    public static int minutesDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/MINUTE_MILLIS) - (earlierDate.getTime()/MINUTE_MILLIS));
    }
    
    /**
     * Get the hours difference
     */
    public static int hoursDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/HOUR_MILLIS) - (earlierDate.getTime()/HOUR_MILLIS));
    }
    
    /**
     * Get the days difference
     */
    public static int daysDiff( Date earlierDate, Date laterDate )
    {
        if( earlierDate == null || laterDate == null ) return 0;
        
        return (int)((laterDate.getTime()/DAY_MILLIS) - (earlierDate.getTime()/DAY_MILLIS));
    }
    
   /**
    * Roll the java.util.Time forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.sql.Time rollTime( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.sql.Time(gc.getTime().getTime());
    }
    
   /**
    * Roll the java.util.Date forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.util.Date rollDateTime( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.util.Date(gc.getTime().getTime());
    }
    
   /**
    * Roll the java.sql.Date forward or backward.
    * @param startDate - The start date
    * @period Calendar.YEAR etc
    * @param amount - Negative to rollbackwards.
    */
    public static java.sql.Date rollDate( java.util.Date startDate, int period, int amount )
    {
        GregorianCalendar gc = new GregorianCalendar();
        gc.setTime(startDate);
        gc.add(period, amount);
        return new java.sql.Date(gc.getTime().getTime());
    }
    
   /**
    * Roll the years forward or backward.
    * @param startDate - The start date
    * @param years - Negative to rollbackwards.
    */
    public static java.sql.Date rollYears( java.util.Date startDate, int years )
    {
        return rollDate( startDate, Calendar.YEAR, years );
    }
   /**
    * Roll the days forward or backward.
    * @param startDate - The start date
    * @param months - Negative to rollbackwards.
    */
    public static java.sql.Date rollMonths( java.util.Date startDate, int months )
    {
        return rollDate( startDate, Calendar.MONTH, months );
    }
   /**
    * Roll the days forward or backward.
    * @param startDate - The start date
    * @param days - Negative to rollbackwards.
    */
    public static java.sql.Date rollDays( java.util.Date startDate, int days )
    {
        return rollDate( startDate, Calendar.DATE, days );
    }
    
     /**
      * Checks the day, month and year are equal.
      */
     public static boolean dateEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;
        
        return d1.getDate() == d2.getDate() &&
               d1.getMonth() == d2.getMonth() &&
               d1.getYear() == d2.getYear();
     }
     
     /**
      * Checks the hour, minute and second are equal.
      */
     public static boolean timeEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;
        
        return d1.getHours() == d2.getHours() &&
               d1.getMinutes() == d2.getMinutes() &&
               d1.getSeconds() == d2.getSeconds();
     }

    /**
      * Checks the second, hour, month, day, month and year are equal.
      */
     public static boolean dateTimeEquals( java.util.Date d1, java.util.Date d2 )
     {
        if( d1 == null || d2 == null ) return false;               
        
        return d1.getDate() == d2.getDate() &&
               d1.getMonth() == d2.getMonth() &&
               d1.getYear() == d2.getYear() &&
               d1.getHours() == d2.getHours() &&
               d1.getMinutes() == d2.getMinutes() &&
               d1.getSeconds() == d2.getSeconds();
     }
     
     /**
     * Convert an Object of type Classs to an Object.
     */
    public static Object toObject( Class clazz, Object value ) throws ParseException
    {
        if( value == null ) return null;
        if( clazz == null ) return value;
        
        if( java.sql.Date.class.isAssignableFrom( clazz ) ) return toDate( value );
        if( java.sql.Time.class.isAssignableFrom( clazz ) ) return toTime( value );
        if( java.sql.Timestamp.class.isAssignableFrom( clazz ) ) return toTimestamp( value );
        if( java.util.Date.class.isAssignableFrom( clazz ) ) return toDateTime( value );
        
        return value;
    }
    
    /**
     * Convert an Object to a DateTime, without an Exception
     */
    public static java.util.Date getDateTime( Object value )
    {
        try
        {
            return toDateTime( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    
    /**
     * Convert an Object to a DateTime.
     */
    public static java.util.Date toDateTime( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.util.Date ) return (java.util.Date)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return IN_DATETIME_FORMAT.parse( (String)value );
        }
                
        return IN_DATETIME_FORMAT.parse( value.toString() );
    }
    
    /**
     * Convert an Object to a Date, without an Exception
     */
    public static java.sql.Date getDate( Object value )
    {
        try
        {
            return toDate( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    /**
     * Convert an Object to a Date.
     */
    public static java.sql.Date toDate( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Date ) return (java.sql.Date)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Date( IN_DATE_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Date( IN_DATE_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Convert an Object to a Time, without an Exception
     */
    public static java.sql.Time getTime( Object value )
    {
        try
        {
            return toTime( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    
    /**
     * Convert an Object to a Time.
     */
    public static java.sql.Time toTime( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Time ) return (java.sql.Time)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Time( IN_TIME_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Time( IN_TIME_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Convert an Object to a Timestamp, without an Exception
     */
    public static java.sql.Timestamp getTimestamp( Object value )
    {
        try
        {
            return toTimestamp( value );
        }
        catch( ParseException pe )
        {
            pe.printStackTrace();
            return null;
        }
    }
    /**
     * Convert an Object to a Timestamp.
     */
    public static java.sql.Timestamp toTimestamp( Object value ) throws ParseException
    {
        if( value == null ) return null;        
        if( value instanceof java.sql.Timestamp ) return (java.sql.Timestamp)value;
        if( value instanceof String )
        {
            if( "".equals( (String)value ) ) return null;
            return new java.sql.Timestamp( IN_TIMESTAMP_FORMAT.parse( (String)value ).getTime() );
        }
                
        return new java.sql.Timestamp( IN_TIMESTAMP_FORMAT.parse( value.toString() ).getTime() );
    }
    
    /**
     * Tells you if the date part of a datetime is in a certain time range.
     */
    public static boolean isTimeInRange( java.sql.Time start, java.sql.Time end, java.util.Date d )
    {
        d=new java.sql.Time(d.getHours(),d.getMinutes(),d.getSeconds());
        
        if (start==null || end==null)
        {
            return false;
        }
        
        if (start.before(end)&&(!(d.after(start)&&d.before(end))))
        {
            return false;
        }
        
        if (end.before(start)&&(!(d.after(end)||d.before(start))))
        {
            return false;
        }   
        return true;
    }
    public static  int getYear( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.YEAR );
    }
    public static int getMonth( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MONTH );
    }
    public static int getDate( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.DATE );
    }
    public static int getHour( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.HOUR );
    }
    public static int getMinute( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MINUTE );
    }
    public static int getSeconds( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.SECOND );
    }
    public static int getMillisecond( Date date )
    {
        calendar.setTime( date );
        return calendar.get( Calendar.MILLISECOND );
    }
    
    /**
     * Convert an Object to a String using Dates
     */
    public static String toString( Object date )
    {
        if( date == null ) return null;
        
        if( java.sql.Timestamp.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_TIMESTAMP_FORMAT.format( date );
        }
        if( java.sql.Time.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_TIME_FORMAT.format( date );
        }
        if( java.sql.Date.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_DATE_FORMAT.format( date );
        }
        if( java.util.Date.class.isAssignableFrom( date.getClass() ) )
        {
            return OUT_DATETIME_FORMAT.format( date );
        }
        
        throw new IllegalArgumentException( "Unsupported type " + date.getClass() );
    }
}





Round this date, leaving the field specified as the most significant field.

  
import java.util.Calendar;
import java.util.Date;
/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


/**
 * <p>A suite of utilities surrounding the use of the
 * {@link java.util.Calendar} and {@link java.util.Date} object.</p>
 * 
 * <p>DateUtils contains a lot of common methods considering manipulations
 * of Dates or Calendars. Some methods require some extra explanation.
 * The truncate and round methods could be considered the Math.floor(),
 * Math.ceil() or Math.round versions for dates
 * This way date-fields will be ignored in bottom-up order.
 * As a complement to these methods we"ve introduced some fragment-methods.
 * With these methods the Date-fields will be ignored in top-down order.
 * Since a date without a year is not a valid date, you have to decide in what
 * kind of date-field you want your result, for instance milliseconds or days.
 * </p>
 *   
 *   
 *
 * @author 
 * @author Phil Steitz
 * @author Robert Scholte
 * @since 2.0
 * @version $Id: DateUtils.java 634096 2008-03-06 00:58:11Z niallp $
 */
public class Main {
  private static final int[][] fields = {
    {Calendar.MILLISECOND},
    {Calendar.SECOND},
    {Calendar.MINUTE},
    {Calendar.HOUR_OF_DAY, Calendar.HOUR},
    {Calendar.DATE, Calendar.DAY_OF_MONTH, Calendar.AM_PM 
        /* Calendar.DAY_OF_YEAR, Calendar.DAY_OF_WEEK, Calendar.DAY_OF_WEEK_IN_MONTH */
    },
    {Calendar.MONTH, DateUtils.SEMI_MONTH},
    {Calendar.YEAR},
    {Calendar.ERA}};
  /**
   * <p>Round this date, leaving the field specified as the most
   * significant field.</p>
   *
   * <p>For example, if you had the datetime of 28 Mar 2002
   * 13:45:01.231, if this was passed with HOUR, it would return
   * 28 Mar 2002 14:00:00.000. If this was passed with MONTH, it
   * would return 1 April 2002 0:00:00.000.</p>
   * 
   * <p>For a date in a timezone that handles the change to daylight
   * saving time, rounding to Calendar.HOUR_OF_DAY will behave as follows.
   * Suppose daylight saving time begins at 02:00 on March 30. Rounding a 
   * date that crosses this time would produce the following values:
   * <ul>
   * <li>March 30, 2003 01:10 rounds to March 30, 2003 01:00</li>
   * <li>March 30, 2003 01:40 rounds to March 30, 2003 03:00</li>
   * <li>March 30, 2003 02:10 rounds to March 30, 2003 03:00</li>
   * <li>March 30, 2003 02:40 rounds to March 30, 2003 04:00</li>
   * </ul>
   * </p>
   * 
   * @param date  the date to work with
   * @param field  the field from <code>Calendar</code>
   *  or <code>SEMI_MONTH</code>
   * @return the rounded date (a different object)
   * @throws IllegalArgumentException if the date is <code>null</code>
   * @throws ArithmeticException if the year is over 280 million
   */
  public static Calendar round(Calendar date, int field) {
      if (date == null) {
          throw new IllegalArgumentException("The date must not be null");
      }
      Calendar rounded = (Calendar) date.clone();
      modify(rounded, field, true);
      return rounded;
  }
  //-----------------------------------------------------------------------
  /**
   * <p>Internal calculation method.</p>
   * 
   * @param val  the calendar
   * @param field  the field constant
   * @param round  true to round, false to truncate
   * @throws ArithmeticException if the year is over 280 million
   */
  private static void modify(Calendar val, int field, boolean round) {
      if (val.get(Calendar.YEAR) > 280000000) {
          throw new ArithmeticException("Calendar value too large for accurate calculations");
      }
      
      if (field == Calendar.MILLISECOND) {
          return;
      }
      // ----------------- Fix for LANG-59 ---------------------- START ---------------
      // see http://issues.apache.org/jira/browse/LANG-59
      //
      // Manually truncate milliseconds, seconds and minutes, rather than using
      // Calendar methods.
      Date date = val.getTime();
      long time = date.getTime();
      boolean done = false;
      // truncate milliseconds
      int millisecs = val.get(Calendar.MILLISECOND);
      if (!round || millisecs < 500) {
          time = time - millisecs;
      }
      if (field == Calendar.SECOND) {
          done = true;
      }
      // truncate seconds
      int seconds = val.get(Calendar.SECOND);
      if (!done && (!round || seconds < 30)) {
          time = time - (seconds * 1000L);
      }
      if (field == Calendar.MINUTE) {
          done = true;
      }
      // truncate minutes
      int minutes = val.get(Calendar.MINUTE);
      if (!done && (!round || minutes < 30)) {
          time = time - (minutes * 60000L);
      }
      // reset time
      if (date.getTime() != time) {
          date.setTime(time);
          val.setTime(date);
      }
      // ----------------- Fix for LANG-59 ----------------------- END ----------------
      boolean roundUp = false;
      for (int i = 0; i < fields.length; i++) {
          for (int j = 0; j < fields[i].length; j++) {
              if (fields[i][j] == field) {
                  //This is our field... we stop looping
                  if (round && roundUp) {
                      if (field == DateUtils.SEMI_MONTH) {
                          //This is a special case that"s hard to generalize
                          //If the date is 1, we round up to 16, otherwise
                          //  we subtract 15 days and add 1 month
                          if (val.get(Calendar.DATE) == 1) {
                              val.add(Calendar.DATE, 15);
                          } else {
                              val.add(Calendar.DATE, -15);
                              val.add(Calendar.MONTH, 1);
                          }
                      } else {
                          //We need at add one to this field since the
                          //  last number causes us to round up
                          val.add(fields[i][0], 1);
                      }
                  }
                  return;
              }
          }
          //We have various fields that are not easy roundings
          int offset = 0;
          boolean offsetSet = false;
          //These are special types of fields that require different rounding rules
          switch (field) {
              case DateUtils.SEMI_MONTH:
                  if (fields[i][0] == Calendar.DATE) {
                      //If we"re going to drop the DATE field"s value,
                      //  we want to do this our own way.
                      //We need to subtrace 1 since the date has a minimum of 1
                      offset = val.get(Calendar.DATE) - 1;
                      //If we"re above 15 days adjustment, that means we"re in the
                      //  bottom half of the month and should stay accordingly.
                      if (offset >= 15) {
                          offset -= 15;
                      }
                      //Record whether we"re in the top or bottom half of that range
                      roundUp = offset > 7;
                      offsetSet = true;
                  }
                  break;
              case Calendar.AM_PM:
                  if (fields[i][0] == Calendar.HOUR_OF_DAY) {
                      //If we"re going to drop the HOUR field"s value,
                      //  we want to do this our own way.
                      offset = val.get(Calendar.HOUR_OF_DAY);
                      if (offset >= 12) {
                          offset -= 12;
                      }
                      roundUp = offset > 6;
                      offsetSet = true;
                  }
                  break;
          }
          if (!offsetSet) {
              int min = val.getActualMinimum(fields[i][0]);
              int max = val.getActualMaximum(fields[i][0]);
              //Calculate the offset from the minimum allowed value
              offset = val.get(fields[i][0]) - min;
              //Set roundUp if this is more than half way between the minimum and maximum
              roundUp = offset > ((max - min) / 2);
          }
          //We need to remove this field
          if (offset != 0) {
              val.set(fields[i][0], val.get(fields[i][0]) - offset);
          }
      }
      throw new IllegalArgumentException("The field " + field + " is not supported");
  }
}





Utilities to working with dates java.util.Date

  

import java.text.DateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Locale;


/**
 * Utilities to working with dates (<tt>java.util.Date</tt>). <p>  
 * 
 * @author Javier Paniza
 * @author Peter Smith
 */
public class Dates {
  
  /**
   * With hour to 0.
   * If day, month and year are 0 return null.
   */ 
  public static Date create(int day, int month, int year) {
    return create(day, month, year, 0, 0, 0);
  }
  
  /**
   * If day, month and year are 0 return null.
   */ 
  public static Date create(int day, int month, int year, int hourofday, int minute, int second) {
    if (day == 0 && month == 0 && year == 0) return null;
    Calendar cal = Calendar.getInstance();
    cal.set(year, month - 1, day, hourofday, minute, second);
    cal.set(Calendar.MILLISECOND, 0);
    return cal.getTime();     
  }
    
  /**
   * Current date without time. 
   */
  public static Date createCurrent() {
    return removeTime(new java.util.Date());
  }
  
  /**
   * Returns the day of date. <p>
   * 
   * If date is null return 0.
   */
  public static int getDay(Date date) {
    if (date == null) return 0;
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    return cal.get(Calendar.DAY_OF_MONTH);
  }
  
  /**
   * Returns the year (4 digits) of date. <o> 
   * 
   * If date is null returns 0.
   */
  public static int getYear(Date date) {
    if (date == null) return 0;
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    return cal.get(Calendar.YEAR);
  }
  
  /**
   * Returns the month (1 to 12) of date. <p>
   * 
   * If date is null returns 0.
   */
  public static int getMonth(Date date) {
    if (date == null) return 0;
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    return cal.get(Calendar.MONTH) + 1;
  } 
  
  /**
   * Put the day to the date. <p>
   * 
   * If date is null it has no effect (but no exception is thrown)
   */
  public static void setDay(Date date, int day) {
    if (date == null) return;
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    cal.set(Calendar.DAY_OF_MONTH, day);
  }
  
  /**
   * Put the month (1 to 12) to the date. <p>
   * 
   * If date is null it has no effect (but no exception is thrown)
   */
  public static void setMonth(Date date, int month) {
    if (date == null) return;
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    cal.set(Calendar.MONTH, month - 1);
  }
  
  /**
   * Put the year to the date. <p>
   * 
   * If date is null it has no effect (but no exception is thrown)
   */
  public static void setYear(Date date, int year) {
    if (date == null) return;
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    cal.set(Calendar.YEAR, year);
  }
  
  
  /**
   * Puts hours, minutes, seconds and milliseconds to zero. <p>
   * 
   * @return The same date sent as argument (a new date is not created). If null
   *      if sent a null is returned.
   */
  public static Date removeTime(Date date) {
    if (date == null) return null;
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    cal.set(Calendar.HOUR_OF_DAY, 0); 
    cal.set(Calendar.MINUTE, 0);    
    cal.set(Calendar.SECOND, 0);
    cal.set(Calendar.MILLISECOND, 0);
    date.setTime(cal.getTime().getTime());
    return date;
  }
  
  /**
   * Returns a clone but without hours, minutes, seconds and milliseconds. <p>
   * 
   * @return If null if sent a null is returned.
   */
  public static Date cloneWithoutTime(Date date) { 
    if (date == null) return null;
    Date result = (Date) date.clone();
    removeTime(result);
    return result;
  }
  
  /**
   * Returns a clone but with 23:59:59:999 for hours, minutes, seconds and milliseconds. <p>
   * 
   * @return The same date sent as argument (a new date is not created). If null
   *      if sent a null is returned.
   */
  public static Date cloneWith2359(Date date) { 
    if (date == null) return null;
    Date result = (Date) date.clone();    
    Calendar cal = Calendar.getInstance();
    cal.setTime(result);
    cal.set(Calendar.HOUR_OF_DAY, 23); 
    cal.set(Calendar.MINUTE, 59);   
    cal.set(Calendar.SECOND, 59);
    cal.set(Calendar.MILLISECOND, 999);
    result.setTime(cal.getTime().getTime());
    return result;
  }
  
    
  /**
   * Creates a java.sql.Date from a java.util.Date. <p>
   * 
   * @param date If null returns null
   */
  public static java.sql.Date toSQL(java.util.Date date) {
    if (date == null) return null;
    return new java.sql.Date(date.getTime());   
  }
  
  
  /**
   * Creates a date with day, month and year of original,
   * but with current time. <p>
   *  
   * @param date  It is not changed
   * @return If arguments is null then is null
   */
  public static java.util.Date withTime(java.util.Date date) {
    if (date == null) return null;
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    int year = cal.get(Calendar.YEAR);
    int month = cal.get(Calendar.MONTH);
    int day = cal.get(Calendar.DAY_OF_MONTH);
    cal.setTime(new java.util.Date());
    cal.set(Calendar.YEAR, year);
    cal.set(Calendar.MONTH, month);
    cal.set(Calendar.DAY_OF_MONTH, day);
    return cal.getTime();
  }
  
  /**
   * Compares if 2 dates are equals at day, month and year
   * level, ignoring time in comparing. 
   * 
   * @param f1 Can be null
   * @param f2 Can be null
   */
  public static boolean isDifferentDay(java.util.Date f1, java.util.Date f2) {
    if (f1 == null && f2 == null) return false;
    if (f1 == null || f2 == null) return true;
    Calendar cal = Calendar.getInstance();
    cal.setTime(f1);
    int dd1 = cal.get(Calendar.DAY_OF_MONTH);
    int mm1 = cal.get(Calendar.MONTH);
    int aa1 = cal.get(Calendar.YEAR);
    cal.setTime(f2);
    int dd2 = cal.get(Calendar.DAY_OF_MONTH);
    int mm2 = cal.get(Calendar.MONTH);
    int aa2 = cal.get(Calendar.YEAR);
    return !(aa1==aa2 && mm1==mm2 && dd1==dd2);
  }
  
  /**
   * Difference of 2 dates in years, months and days. <p>  
   *  
   * @param f1  If null returns null
   * @param f2  If null returns null 
   */ 
  public static DateDistance dateDistance(java.util.Date f1, java.util.Date f2, boolean includeStartDate ) {
    DateDistance df = new DateDistance();
    if (null == f1 || null == f2)
      return null;
    Calendar fmax = Calendar.getInstance(), fmin = Calendar.getInstance();
    f1 = Dates.removeTime(f1);
    f2 = Dates.removeTime(f2);
    if (f1.after(f2)) {
      fmax.setTime(f1);
      fmin.setTime(f2);
    } 
    else {
      fmin.setTime(f1);
      fmax.setTime(f2);
    }
        
    int initDay = fmin.get(Calendar.DATE);
    int initMonth = fmin.get(Calendar.MONTH);
    int initYear = fmin.get(Calendar.YEAR);
    int endMonth = fmax.get(Calendar.MONTH);
    int endYear = fmax.get(Calendar.YEAR);
    int finalLimit = fmax.getActualMaximum(Calendar.DATE);
    int initPeak = 0;
    int finalPeak = 0;
        
    if (initMonth == endMonth && initYear == endYear) {
      while ( fmin.getTime().before(fmax.getTime()) ) {
        fmin.add(Calendar.DATE, 1);
        df.days++;
      }
      if (includeStartDate) {
        df.days++;
      }
      if (df.days >= finalLimit) {
        df.months++;
        df.days = 0;
      }
      return df;
    }
        
    if (initDay != 1) {
      while (fmin.get(Calendar.DATE) != 1) {
        fmin.add(Calendar.DATE, 1);
        initPeak++;
      }
    }
        
    while (fmin.get(Calendar.MONTH) != endMonth
        || fmin.get(Calendar.YEAR) != endYear) {
      fmin.add(Calendar.MONTH, 1);
      df.months++;
      if (df.months == 12) {
        df.years++;
        df.months = 0;
      }
    }
        
    while ( fmin.getTime().before(fmax.getTime()) ) {
      fmin.add(Calendar.DATE, 1);
      finalPeak++;
    }
        
    int peak = initPeak + finalPeak;
    if (includeStartDate) {
      peak++;
    }
        
    if (peak >= finalLimit) {
      peak = peak - finalLimit;
      df.months++;
      if (df.months == 12) {
        df.years++;
        df.months = 0;
      }
    }
    df.days = peak;
    return df;        
  }
  /**
   * Difference of 2 dates in years, months and days. <p>  
   *  
   * @param f1  If null returns null
   * @param f2  If null returns null 
   */ 
  public static DateDistance dateDistance(java.util.Date f1, java.util.Date f2) {
    return dateDistance(f1, f2, false);   
  }
    
  public static DateDistance addDateDistances(DateDistance dis1, DateDistance dis2) {
    DateDistance df=new DateDistance();
    if ( null == dis1 || null == dis2 ) return null;
        
    int years, months, days;
    days = dis1.days + dis2.days;
    months = days / 30;
    days = days % 30;
    
    months = months + dis1.months + dis2.months ;
    years =  months / 12 ;
    months = months % 12;   
        
    years = years + ( dis1.years + dis2.years );
    df.years = years;
    df.months=months;
    df.days=days;
        
    return df;
  }
  
  
  public static DateDistance subtractDateDistances(DateDistance dis1, DateDistance dis2) {
    DateDistance df = new DateDistance();
    if ( null == dis1 || null == dis2 ) return null;
        
    int years=0;
    int months=0;
    int days=0;
    days = dis1.days - dis2.days;
    months = dis1.months - dis2.months;
    years =dis1.years - dis2.years;
      
    if (days<0) {
      days=days+30;
      months=months-1;
    }
    if (months<0){
      months=months+12;
      years=years-1;
    }
      
    df.years = years;
    df.months = months;
    df.days = days;
        
    return df;
  }
  
  public static String dateFormatForJSCalendar(Locale locale) {   
    DateFormat df = DateFormat.getDateInstance(DateFormat.SHORT, locale);
    String date = df.format(create(1, 2, 1971)); // d, m, y
    boolean always4InYear= "es".equals(locale.getLanguage()) || "pl".equals(locale.getLanguage());
    String result = date.
      replaceAll("01", "%d").
      replaceAll("02", "%m").
      replaceAll("1971", "%Y").
      replaceAll("71", always4InYear?"%Y":"%y").      
      replaceAll("1", "%d").
      replaceAll("2", "%m");
    return result;
  } 
  
  public static String dateTimeFormatForJSCalendar(Locale locale) {   
    DateFormat df = DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.SHORT, locale);
    String datetime = df.format(create(1, 2, 1971, 15, 59, 0)); // d, m, y, hr, min, sec 
    boolean always4InYear= "es".equals(locale.getLanguage()) || "pl".equals(locale.getLanguage());
    String result = datetime.
    
      // time part
      replaceAll("15", "%H"). // 24hr format 
      replaceAll("03", "%I"). // 12hr format - double digit 
      replaceAll("3", "%l").  // 12hr format - single digit
      replaceAll("59","%M").  // minute
      replaceAll("PM", "%p"). // AM/PM - uppercase
      replaceAll("pm", "%P"). // am/pm - lowercase
      // date part
      replaceAll("01", "%d"). // day - double digit
      replaceAll("02", "%m"). // month - double digit
      replaceAll("1971", "%Y"). // year - 4 digit
      replaceAll("71", always4InYear?"%Y":"%y").  // year - 2 digit     
      replaceAll("1", "%e").  // day - single digit
      replaceAll("2", "%m") // month - ??? seems only double digit is supported by calendar
      ;
          
    return result;
  } 
  
  /** 
   * Returns number of days between startDate and endDate<p> 
   *  
   * @param java.util.Date startDate
   * @param java.util.Date endDate
   * @param boolean includeStartDate<p>
   *  
   */ 
    public static int daysInterval (Date startDate, Date endDate,
        boolean includeStartDate ) {
    
    startDate = Dates.removeTime(startDate);
    Calendar start = Calendar.getInstance();
    start.setTime(startDate);   
    endDate = Dates.removeTime(endDate);    
    Calendar end = Calendar.getInstance();
    end.setTime(endDate);
    
    if (includeStartDate) {
      start.add(Calendar.DATE, -1);
    }
    
    int days = 0;
    while (start.before(end)) {
      days++;
      start.add(Calendar.DATE,1);
    }
    return days;
  }
    
    
   
  
  public static class DateDistance {
    public  int days;
    public  int months;
    public  int years;
  }
  
}