Java/File Input Output/Text Read Write

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An iterator that breaks text into lines. The result is equal to BufferedReader.readLine().

    
/* 
 * JCommon : a free general purpose class library for the Java(tm) platform
 * 
 *
 * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
 * 
 * Project Info:  http://www.jfree.org/jcommon/index.html
 *
 * This library is free software; you can redistribute it and/or modify it 
 * under the terms of the GNU Lesser General Public License as published by 
 * the Free Software Foundation; either version 2.1 of the License, or 
 * (at your option) any later version.
 *
 * This library 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 Lesser General Public 
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
 * USA.  
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
 * in the United States and other countries.]
 *
 * ----------------------
 * LineBreakIterator.java
 * ----------------------
 * (C)opyright 2003, by Thomas Morgner and Contributors.
 *
 * Original Author:  Thomas Morgner;
 * Contributor(s):   David Gilbert (for Object Refinery Limited);
 *
 * $Id: LineBreakIterator.java,v 1.4 2005/11/03 09:55:26 mungady Exp $
 *
 * Changes
 * -------
 * 13-03-2003 : Initial version
 */
import java.util.Iterator;
/**
 * An iterator that breaks text into lines. The result is equal to
 * BufferedReader.readLine().
 * 
 * @author Thomas Morgner
 */
public class LineBreakIterator implements Iterator {
  /** A useful constant. */
  public static final int DONE = -1;
  /** Storage for the text. */
  private char[] text;
  /** The current position. */
  private int position;
  /**
   * Default constructor.
   */
  public LineBreakIterator() {
    setText("");
  }
  /**
   * Creates a new line break iterator.
   * 
   * @param text
   *          the text to be broken up.
   */
  public LineBreakIterator(final String text) {
    setText(text);
  }
  /**
   * Returns the position of the next break.
   * 
   * @return A position.
   */
  public synchronized int nextPosition() {
    if (this.text == null) {
      return DONE;
    }
    if (this.position == DONE) {
      return DONE;
    }
    // recognize \n, \r, \r\n
    final int nChars = this.text.length;
    int nextChar = this.position;
    for (;;) {
      if (nextChar >= nChars) {
        /* End of text reached */
        this.position = DONE;
        return DONE;
      }
      boolean eol = false;
      char c = 0;
      int i;
      // search the next line break, either \n or \r
      for (i = nextChar; i < nChars; i++) {
        c = this.text[i];
        if ((c == "\n") || (c == "\r")) {
          eol = true;
          break;
        }
      }
      nextChar = i;
      if (eol) {
        nextChar++;
        if (c == "\r") {
          if ((nextChar < nChars) && (this.text[nextChar] == "\n")) {
            nextChar++;
          }
        }
        this.position = nextChar;
        return (this.position);
      }
    }
  }
  /**
   * Same like next(), but returns the End-Of-Text as if there was a linebreak
   * added (Reader.readLine() compatible)
   * 
   * @return The next position.
   */
  public int nextWithEnd() {
    final int pos = this.position;
    if (pos == DONE) {
      return DONE;
    }
    if (pos == this.text.length) {
      this.position = DONE;
      return DONE;
    }
    final int retval = nextPosition();
    if (retval == DONE) {
      return this.text.length;
    }
    return retval;
  }
  /**
   * Returns the text to be broken up.
   * 
   * @return The text.
   */
  public String getText() {
    return new String(this.text);
  }
  /**
   * Sets the text to be broken up.
   * 
   * @param text
   *          the text.
   */
  public void setText(final String text) {
    this.position = 0;
    this.text = text.toCharArray();
  }
  /**
   * Returns <tt>true</tt> if the iteration has more elements. (In other
   * words, returns <tt>true</tt> if <tt>next</tt> would return an element
   * rather than throwing an exception.)
   * 
   * @return <tt>true</tt> if the iterator has more elements.
   */
  public boolean hasNext() {
    return (this.position != DONE);
  }
  /**
   * Returns the next element in the iteration.
   * 
   * @return the next element in the iteration.
   */
  public Object next() {
    if (this.position == DONE) {
      // allready at the end ...
      return null;
    }
    final int lastFound = this.position;
    int pos = nextWithEnd();
    if (pos == DONE) {
      // the end of the text has been reached ...
      return new String(this.text, lastFound, this.text.length - lastFound);
    }
    // step one char back
    if (pos > 0) {
      final int end = lastFound;
      for (; ((pos) > end) && ((this.text[pos - 1] == "\n") || this.text[pos - 1] == "\r"); pos--) {
        // search the end of the current linebreak sequence ..
      }
    }
    // System.out.println ("text: " + new String (text));
    // System.out.println ("pos: " + pos + " lastFound: " + lastFound);
    return new String(this.text, lastFound, pos - lastFound);
  }
  /**
   * 
   * Removes from the underlying collection the last element returned by the
   * iterator (optional operation). This method can be called only once per call
   * to <tt>next</tt>. The behavior of an iterator is unspecified if the
   * underlying collection is modified while the iteration is in progress in any
   * way other than by calling this method.
   * 
   * @exception UnsupportedOperationException
   *              if the <tt>remove</tt> operation is not supported by this
   *              Iterator.
   * @exception IllegalStateException
   *              if the <tt>next</tt> method has not yet been called, or the
   *              <tt>remove</tt> method has already been called after the
   *              last call to the <tt>next</tt> method.
   */
  public void remove() {
    throw new UnsupportedOperationException("This iterator is read-only.");
  }
}





Compare text file line by line

 
/*   
* Copyright 2004 The Apache Software Foundation
*
*   Licensed 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.
*/
//based on Apache technology http://www.apache.org
import java.io.IOException;
import java.io.LineNumberReader;
import java.io.Reader;
import java.util.List;

public class Diff
{
    public static void readersAsText(Reader r1, String name1, Reader r2, String name2,
        List diffs)
        throws IOException
    {
        LineNumberReader reader1 = new LineNumberReader(r1);
        LineNumberReader reader2 = new LineNumberReader(r2);
        String line1 = reader1.readLine();
        String line2 = reader2.readLine();
        while (line1 != null && line2 != null)
        {
            if (!line1.equals(line2))
            {
                diffs.add("File \"" + name1 + "\" and file \"" +
                    name2 + "\" differ at line " + reader1.getLineNumber() +
                    ":" + "\n" + line1 + "\n" + line2);
                break;
            }
            line1 = reader1.readLine();
            line2 = reader2.readLine();
        }
        if (line1 == null && line2 != null)
            diffs.add("File \"" + name2 + "\" has extra lines at line " +
                reader2.getLineNumber() + ":\n" + line2);
        if (line1 != null && line2 == null)
            diffs.add("File \"" + name1 + "\" has extra lines at line " +
                reader1.getLineNumber() + ":\n" + line1);
    }
}





CRLF Print Writer

     

/* -----------------------------------------------------------
 * nntp//rss - a bridge between the RSS world and NNTP clients
 * Copyright (c) 2002, 2003 Jason Brome.  All Rights Reserved.
 *
 * email: nntprss@methodize.org
 * mail:  Methodize Solutions
 *        PO Box 3865
 *        Grand Central Station
 *        New York NY 10163
 * 
 * This file is part of nntp//rss
 * 
 * nntp//rss 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; 
 * either version 2 of the License, or (at your option) any 
 * later version.
 *
 * 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.io.OutputStream;
import java.io.PrintWriter;
import java.io.Writer;
/**
 * 
 * Wrapper class - used for output writer in NNTP communications
 * All lines must end in CR/LF - if println is used in
 * standard PrintWriter implementation, platform specific
 * line termination will be used - e.g. \r\n *or* \n
 * 
 * @author Jason Brome <jason@methodize.org>
 * @version $Id: CRLFPrintWriter.java,v 1.3 2003/01/22 05:11:23 jasonbrome Exp $
 */
public class CRLFPrintWriter extends PrintWriter {
  
  private static final String CRLF = "\r\n";
  
  public CRLFPrintWriter(OutputStream out) {
    super(out);
  }
  
  public CRLFPrintWriter(OutputStream out, boolean autoFlush) {
    super(out, autoFlush);
  }
  public CRLFPrintWriter(Writer out) {
    super(out);
  }
  
  public CRLFPrintWriter(Writer out, boolean autoFlush) {
    super(out, autoFlush);
  }
  
  
  /**
   * @see java.io.PrintWriter#println()
   */
  public void println() {
    super.print(CRLF);
  }
  /**
   * @see java.io.PrintWriter#println(boolean)
   */
  public void println(boolean arg0) {
    super.print(arg0);
    println();
  }
  /**
   * @see java.io.PrintWriter#println(char)
   */
  public void println(char arg0) {
    super.print(arg0);
    println();
  }
  /**
   * @see java.io.PrintWriter#println(char[])
   */
  public void println(char[] arg0) {
    super.print(arg0);
    println();
  }
  /**
   * @see java.io.PrintWriter#println(double)
   */
  public void println(double arg0) {
    super.print(arg0);
    println();
  }
  /**
   * @see java.io.PrintWriter#println(float)
   */
  public void println(float arg0) {
    super.print(arg0);
    println();
  }
  /**
   * @see java.io.PrintWriter#println(int)
   */
  public void println(int arg0) {
    super.print(arg0);
    println();
  }
  /**
   * @see java.io.PrintWriter#println(long)
   */
  public void println(long arg0) {
    super.print(arg0);
    println();
  }
  /**
   * @see java.io.PrintWriter#println(Object)
   */
  public void println(Object arg0) {
    super.print(arg0);
    println();
  }
  /**
   * @see java.io.PrintWriter#println(String)
   */
  public void println(String arg0) {
    super.print(arg0);
    println();
  }
}





CRLF Terminated Reader

     
/****************************************************************
 * 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.                                           *
 ****************************************************************/

import java.io.InputStream;
import java.io.Reader;
import java.io.UnsupportedEncodingException;
import java.io.IOException;
/**
 * A Reader for use with SMTP or other protocols in which lines
 * must end with CRLF.  Extends Reader and overrides its 
 * readLine() method.  The Reader readLine() method cannot
 * serve for SMTP because it ends lines with either CR or LF alone. 
 */
public class CRLFTerminatedReader extends Reader {
    public class TerminationException extends IOException {
        private int where;
        public TerminationException(int where) {
            super();
            this.where = where;
        }
        public TerminationException(String s, int where) {
            super(s);
            this.where = where;
        }
        public int position() {
            return where;
        }
    }
    public class LineLengthExceededException extends IOException {
        public LineLengthExceededException(String s) {
            super(s);
        }
    }
    /**
     * Constructs this CRLFTerminatedReader.
     * @param in an InputStream
     * @param charsetName the String name of a supported charset.  
     * "ASCII" is common here.
     * @throws UnsupportedEncodingException if the named charset
     * is not supported
     */
    InputStream in;
    public CRLFTerminatedReader(InputStream in) {
    this.in = in;
    }
    public CRLFTerminatedReader(InputStream in, String enc) throws UnsupportedEncodingException {
        this(in);
    }
    private StringBuffer lineBuffer = new StringBuffer();
    private final int
            EOF = -1,
            CR  = 13,
            LF  = 10;
    private int tainted = -1;
    /**
     * Read a line of text which is terminated by CRLF.  The concluding
     * CRLF characters are not returned with the String, but if either CR
     * or LF appears in the text in any other sequence it is returned
     * in the String like any other character.  Some characters at the 
     * end of the stream may be lost if they are in a "line" not
     * terminated by CRLF.
     * 
     * @return either a String containing the contents of a 
     * line which must end with CRLF, or null if the end of the 
     * stream has been reached, possibly discarding some characters 
     * in a line not terminated with CRLF. 
     * @throws IOException if an I/O error occurs.
     */
    public String readLine() throws IOException{
        //start with the StringBuffer empty
        lineBuffer.delete(0, lineBuffer.length());
        /* This boolean tells which state we are in,
         * depending upon whether or not we got a CR
         * in the preceding read().
         */ 
        boolean cr_just_received = false;
        // Until we add support for specifying a maximum line lenth as
        // a Service Extension, limit lines to 2K, which is twice what
        // RFC 2821 4.5.3.1 requires.
        while (lineBuffer.length() <= 2048) {
            int inChar = read();
            if (!cr_just_received){
                //the most common case, somewhere before the end of a line
                switch (inChar){
                    case CR  :  cr_just_received = true;
                                break;
                    case EOF :  return null;   // premature EOF -- discards data(?)
                    case LF  :  //the normal ending of a line
                        if (tainted == -1) tainted = lineBuffer.length();
                        // intentional fall-through
                    default  :  lineBuffer.append((char)inChar);
                }
            }else{
                // CR has been received, we may be at end of line
                switch (inChar){
                    case LF  :  // LF without a preceding CR
                        if (tainted != -1) {
                            int pos = tainted;
                            tainted = -1;
                            throw new TerminationException("\"bare\" CR or LF in data stream", pos);
                        }
                        return lineBuffer.toString();
                    case EOF :  return null;   // premature EOF -- discards data(?)
                    case CR  :  //we got two (or more) CRs in a row
                        if (tainted == -1) tainted = lineBuffer.length();
                        lineBuffer.append((char)CR);
                        break;
                    default  :  //we got some other character following a CR
                        if (tainted == -1) tainted = lineBuffer.length();
                        lineBuffer.append((char)CR);
                        lineBuffer.append((char)inChar);
                        cr_just_received = false;
                }
            }
        }//while
        throw new LineLengthExceededException("Exceeded maximum line length");
    }//method readLine()
    public int read() throws IOException {
    return in.read();
    }
    public boolean ready() throws IOException {
    return in.available() > 0;
    }
    public int read(char cbuf[], int  off, int  len) throws IOException {
    byte [] temp = new byte[len];
    int result = in.read(temp, 0, len);
    for (int i=0;i<result;i++) cbuf[i] = (char) temp[i];
    return result;
    }
    public void close() throws IOException {
    in.close();
    }
}





Data Text Writer

   
//** 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 ***************************************************

/////////////////////////
//$Archive: /JADE/SourceCode/com/salmonllc/util/DataTextWriter.java $
//$Author: Dan $ 
//$Revision: 7 $ 
//$Modtime: 10/30/02 2:59p $ 
/////////////////////////
 
import java.util.*;
import java.io.*;
/**
 * This object allows you to write a flat text file with data elements separated by Separators and such. 
 */
public class DataTextWriter {
  private int NumColumns=0;
  private Vector[] Columns;
  private String LineBreak="\r\n";
  private String Separator=",";
  private boolean Quoted=false;
  private char QuoteCharacter="\0";
  private StringBuffer sbTextBuffer=new StringBuffer();
/**
 * Builds a DataTextWriter with each row containing iNumColumns.
 * @param iNumCols The number of columns in a row of the DataTextWriter.
 */ 
public DataTextWriter(int iNumCols) {
  this(iNumCols,"","","\0",false);
}
/**
 * Builds a DataTextWriter with each row containing iNumCols and each piece of Data separated by sSeparator.
 * @param iNumCols The number of columns in a row of the DataTextWriter.
 * @param sSeparator The separator used to separate data columns in a row.
 */ 
public DataTextWriter(int iNumCols,String sSeparator) {
  this(iNumCols,sSeparator,"","\0",false);
}
/**
 * Builds a DataTextWriter with each row containing iNumCols and each piece of Data separated by sSeparator 
 * and row separated by sLineBreak.
 * @param iNumCols The number of columns in a row of the DataTextWriter.
 * @param sSeparator The separator used to separate data columns in a row.
 * @param sLineBreak The separator used to separate individual rows.
 */ 
 
public DataTextWriter(int iNumCols,String sSeparator,String sLineBreak) {
  this(iNumCols,sSeparator,sLineBreak,"\0",false);
}
/**
 * Builds a DataTextWriter with each row containing iNumColumns and each piece of Data separated by sSeparator 
 * and row separated by sLineBreak and each piece of Data is surrounded by cQuoteChar if bQuoted is true.
 * @param iNumCols The number of columns in a row of the DataTextWriter.
 * @param sSeparator The separator used to separate data columns in a row.
 * @param sLineBreak The separator used to separate individual rows.
 * @param cQuoteChar The character used to quote indivividual data columns.
 * @param bQuoted The flag to indicate if data columns are to be quoted.
 */ 
public DataTextWriter(int iNumCols,String sSeparator,String sLineFeed,char cQuoteChar,boolean bQuoted) {
  NumColumns=iNumCols;
  Separator=sSeparator;
  LineBreak=sLineFeed;
  QuoteCharacter=cQuoteChar;
  Quoted=bQuoted;
  Columns=new Vector[iNumCols];
  for (int i=0;i<iNumCols;i++)
    Columns[i]=new Vector(100,100);
}
/**
 * Adds a piece of data to a specific column in this DataTextWriter. 
 * @param iColumn The column which the specified data belongs to.
 * @param sData The data for the specified column.
 */ 
 
public void addData(int iColumn,String sData) throws Exception {
  if (iColumn<0 || iColumn>=NumColumns)
    throw new Exception("Column Index is out of range. Valid Range is (0-"+(NumColumns-1)+").");
  Columns[iColumn].addElement(sData);
  int iCount=Columns[0].size(); 
  for (int i=1;i<NumColumns;i++)
     if (Columns[i].size()!=iCount)
       return;
  int i=Columns[iColumn].size()-1;
  for (int j=0;j<(NumColumns-1);j++) {
    if (Quoted) 
      sbTextBuffer.append(QuoteCharacter+(String)Columns[j].elementAt(i)+QuoteCharacter+Separator);
    else
    sbTextBuffer.append((String)Columns[j].elementAt(i)+Separator);
   }
  if (Quoted) 
    sbTextBuffer.append(QuoteCharacter+(String)Columns[NumColumns-1].elementAt(i)+QuoteCharacter+LineBreak);
  else
    sbTextBuffer.append((String)Columns[NumColumns-1].elementAt(i)+LineBreak);
}
/**
 * This method returns the Data in DataTextWriter in formatted output string.
 * @return Formatted Output
 */
public String getText() /*throws DataTextWriterException*/ {
//  StringBuffer sb=new StringBuffer();
/*  int iCount=Columns[0].size(); 
  for (int i=1;i<NumColumns;i++)
     if (Columns[i].size()!=iCount)
       throw new DataTextWriterException("There is not an equal number data values in each column.");*/
/*  for (int i=0;i<iCount;i++) {
    for (int j=0;j<NumColumns-1;j++) {
    if (Quoted) 
        sb.append(QuoteCharacter+(String)Columns[j].elementAt(i)+QuoteCharacter+Separator);
    else
      sb.append((String)Columns[j].elementAt(i)+Separator);
     }
    if (Quoted) 
    sb.append(QuoteCharacter+(String)Columns[NumColumns-1].elementAt(i)+QuoteCharacter+LineBreak);
    else
    sb.append((String)Columns[NumColumns-1].elementAt(i)+LineBreak);
   } */
  return sbTextBuffer.toString();
}
/**
 * This method returns the length of the Data in DataTextWriter in formatted output string.
 * @return Formatted Output
 */
public int getTextLength() {
  return sbTextBuffer.length();
}
/**
 * Sets the LineBreak Separator in this DataTextWriter. 
 * @param sLineBreak The separator used to separate individual rows.
 */ 
public void setLineBreak(String sLineBreak) {
  LineBreak=sLineBreak;
}
/**
 * Sets the Character to be used for Quoting Data Columns in this DataTextWriter. 
 * @param cQuoteChar The character used to quote individual data columns.
 */ 
public void setQuoteCharacter(char cQuoteChar) {
  QuoteCharacter=cQuoteChar;
}
/**
 * Sets the Flag to to inicate that Data Columns are to be quoted in this DataTextWriter. 
 * @param bQuoted The flag used to indicate if data columns are quoted.
 */ 
public void setQuoted(boolean bQuoted) {
  Quoted=bQuoted;
}
/**
 * Sets the Separator to be used for separating individual Data Columns in this DataTextWriter. 
 * @param sSeparator The separator used to separate individual data columns.
 */ 
public void setSeparator(String sSeparator) {
  Separator=sSeparator;
}
/**
 * This method creates a flat file containing the data added to this DataTextWriter.
 * @param sFilename The name of flat file to create.
 */
public void writeFile(String sFilename) throws Exception {
  try {
    FileOutputStream fos=new FileOutputStream(sFilename);
    PrintWriter pw=new PrintWriter(fos);
    pw.print(getText());
    pw.close();
    fos.close();
   }
  catch(Exception e) {
    throw new Exception(e.getMessage());
   }            
}
}





Dump a String to a text file with encoding.

   

/*
 * 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.
 */
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;

public class Main {

  /**
   * Dump a <code>String</code> to a text file.
   *
   * @param file The output file
   * @param string The string to be dumped
   * @param encoding The encoding for the output file or null for default platform encoding
   * @exception IOException IO Error
   */
  public static void serializeString(File file, String string, String encoding)
  throws IOException {
      final Writer fw =
              (encoding == null)?
              new FileWriter(file):
              new OutputStreamWriter(new FileOutputStream(file), encoding);
      try {
          fw.write(string);
          fw.flush();
      } finally {
          fw.close();
      }
  }
}





Find a pattern within a file

     
/*
 * @(#)Grep.java  1.3 01/12/13
 * Search a list of files for lines that match a given regular-expression
 * pattern.  Demonstrates NIO mapped byte buffers, charsets, and regular
 * expressions.
 *
 * Copyright 2001-2002 Sun Microsystems, Inc. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or 
 * without modification, are permitted provided that the following 
 * conditions are met:
 * 
 * -Redistributions of source code must retain the above copyright  
 * notice, this  list of conditions and the following disclaimer.
 * 
 * -Redistribution in binary form must reproduct the above copyright 
 * notice, this list of conditions and the following disclaimer in 
 * the documentation and/or other materials provided with the 
 * distribution.
 * 
 * Neither the name of Sun Microsystems, Inc. or the names of 
 * contributors may be used to endorse or promote products derived 
 * from this software without specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any 
 * kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND 
 * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY 
 * EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY 
 * DAMAGES OR LIABILITIES  SUFFERED BY LICENSEE AS A RESULT OF  OR 
 * RELATING TO USE, MODIFICATION OR DISTRIBUTION OF THE SOFTWARE OR 
 * ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE 
 * FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, 
 * SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER 
 * CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF 
 * THE USE OF OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN 
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 * 
 * You acknowledge that Software is not designed, licensed or 
 * intended for use in the design, construction, operation or 
 * maintenance of any nuclear facility. 
 */
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.nio.CharBuffer;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;
/**
 * This is a utility class to find a pattern within a file, specifically the
 * sense.idx file.
 * 
 * @author brett
 * 
 */
public class Grep {
  /**
   * Set the character set for the file.
   */
  private static Charset charset = Charset.forName("ISO-8859-15");
  /**
   * The decoder for the file.
   */
  private static CharsetDecoder decoder = charset.newDecoder();
  /**
   * Line parsing pattern.
   */
  private static Pattern linePattern = Pattern.rupile(".*\r?\n");
  /**
   * Input pattern we"re looking for.
   */
  private static Pattern pattern;
  /**
   * The character buffer reference.
   */
  private static CharBuffer indexFile;
  /**
   * Compiles the pattern.
   * 
   * @param pat
   *          regex
   */
  private static void compile(String pat) {
    try {
      pattern = Pattern.rupile(pat);
    } catch (PatternSyntaxException x) {
      System.err.println(x.getMessage());
    }
  }
  /**
   * Use the linePattern to break the given CharBuffer into lines, applying the
   * input pattern to each line to see if we have a match
   */
  private static List grep() {
    List matches = new ArrayList();
    Matcher lm = linePattern.matcher(indexFile); // Line matcher
    Matcher pm = null; // Pattern matcher
    int lines = 0;
    while (lm.find()) {
      lines++;
      CharSequence cs = lm.group(); // The current line
      if (pm == null)
        pm = pattern.matcher(cs);
      else
        pm.reset(cs);
      if (pm.find()) {
        matches.add(cs.toString());
      }
      if (lm.end() == indexFile.limit())
        break;
    }
    return matches;
  }
  public static void setFile(File f) throws IOException {
    FileInputStream fis = new FileInputStream(f);
    FileChannel fc = fis.getChannel();
    // Get the file"s size and then map it into memory
    int sz = (int) fc.size();
    MappedByteBuffer bb = fc.map(FileChannel.MapMode.READ_ONLY, 0, sz);
    // Decode the file into a char buffer
    indexFile = decoder.decode(bb);
    fc.close();
  }
  /**
   * Search for occurrences in the given file of the offset, then find the
   * appropriate lemma.
   * 
   * @param f
   * @param synsetOffset
   * @return
   * @throws IOException
   */
  public static List grep(String synsetOffset) throws IOException {
    compile(synsetOffset);
    // Perform the search
    List matches = grep();
    return matches;
  }
  /**
   * Search for occurrences in the given file of the offset, then find the
   * appropriate lemma.
   * 
   * @param f
   * @param synsetOffset
   * @return
   * @throws IOException
   */
  public static String grep(String synsetOffset, String lemma) throws IOException {
    compile(synsetOffset);
    String m = "";
    // Perform the search
    List matches = grep();
    for (int i = 0; i < matches.size(); i++) {
      String match = (String) matches.get(i);
      if (match.indexOf(lemma) != -1) {
        m = match;
      }
    }
    return m;
  }
}





Gets the content from a File as String Array List

     
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FilenameFilter;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Iterator;
/*
 * IzPack - Copyright 2001-2008 Julien Ponge, All Rights Reserved.
 *
 * http://izpack.org/
 * http://izpack.codehaus.org/
 *
 * Copyright 2005 Marc Eppelmann
 *
 * Licensed 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.
 */

/**
 * Provides general global file utility methods
 *
 * @author marc.eppelmann
 */
class FileUtil
{
    //~ Constructors ***********************************************************************
    /**
     * Creates a new FileUtil object.
     */
    public FileUtil()
    {
    }
    //~ Methods ****************************************************************************
    /**
     * Gets the content from a File as StringArray List.
     *
     * @param fileName A file to read from.
     * @return List of individual line of the specified file. List may be empty but not
     *         null.
     * @throws IOException
     */
    public static ArrayList getFileContent(String fileName)
            throws IOException
    {
        ArrayList result = new ArrayList();
        File aFile = new File(fileName);
        if (!aFile.isFile())
        {
            //throw new IOException( fileName + " is not a regular File" );
            return result; // None
        }
        BufferedReader reader = null;
        try
        {
            reader = new BufferedReader(new FileReader(aFile));
        }
        catch (FileNotFoundException e1)
        {
            // TODO handle Exception
            e1.printStackTrace();
            return result;
        }
        String aLine = null;
        while ((aLine = reader.readLine()) != null)
        {
            result.add(aLine + "\n");
        }
        reader.close();
        return result;
    }
    /**
     * Searches case sensitively, and returns true if the given SearchString occurs in the
     * first File with the given Filename.
     *
     * @param aFileName     A files name
     * @param aSearchString the string search for
     * @return true if found in the file otherwise false
     */
    public static boolean fileContains(String aFileName, String aSearchString)
    {
        return (fileContains(aFileName, aSearchString, false));
    }
    /**
     * Tests if the given File contains the given Search String
     *
     * @param aFileName             A files name
     * @param aSearchString         the String to search for
     * @param caseInSensitiveSearch If false the Search is casesensitive
     * @return true if found in the file otherwise false
     */
    public static boolean fileContains(String aFileName, String aSearchString,
                                       boolean caseInSensitiveSearch)
    {
        boolean result = false;
        String searchString = caseInSensitiveSearch
                ? aSearchString.toLowerCase() : aSearchString;
        ArrayList fileContent = new ArrayList();
        try
        {
            fileContent = getFileContent(aFileName);
        }
        catch (IOException e)
        {
            // TODO handle Exception
            e.printStackTrace();
        }
        Iterator linesIter = fileContent.iterator();
        while (linesIter.hasNext())
        {
            String currentline = (String) linesIter.next();
            if (caseInSensitiveSearch)
            {
                currentline = currentline.toLowerCase();
            }
            if (currentline.indexOf(searchString) > -1)
            {
                result = true;
                break;
            }
        }
        return result;
    }
    /**
     * Gets file date and time.
     *
     * @param url The URL of the file for which date and time will be returned.
     * @return Returns long value which is the date and time of the file. If any error
     *         occures returns -1 (=no file date and time available).
     */
    public static long getFileDateTime(URL url)
    {
        if (url == null)
        {
            return -1;
        }
        String fileName = url.getFile();
        if (fileName.charAt(0) == "/" || fileName.charAt(0) == "\\")
        {
            fileName = fileName.substring(1, fileName.length());
        }
        try
        {
            File file = new File(fileName);
            // File name must be a file or a directory.
            if (!file.isDirectory() && !file.isFile())
            {
                return -1;
            }
            return file.lastModified();
        }
        catch (java.lang.Exception e)
        {   // Trap all Exception based exceptions and return -1.
            return -1;
        }
    }
    public static String[] getFileNames(String dirPath) throws Exception
    {
        return getFileNames(dirPath, null);
    }
    public static String[] getFileNames(String dirPath, FilenameFilter fileNameFilter) throws Exception
    {
        String fileNames[] = null;
        File dir = new File(dirPath);
        if (dir.isDirectory())
        {
            if (fileNameFilter != null)
            {
                fileNames = dir.list(fileNameFilter);
            }
            else
            {
                fileNames = dir.list();
            }
        }
        return fileNames;
    }
    /**
     * Test main
     *
     * @param args
     */
    public static void main(String[] args)
    {
    }
}





Java File Generator

     
/* Copyright (c) 2008, Paul Cager.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *     * Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.Map;
/**
 * Generates boiler-plate files from templates. Only very basic
 * template processing is supplied - if we need something more
 * sophisticated I suggest we use a third-party library.
 * 
 * @author paulcager
 * @since 4.2
 */
public class JavaFileGenerator {
  /**
   * @param templateName the name of the template. E.g. 
   *        "/templates/Token.template".
   * @param options the processing options in force, such
   *        as "STATIC=yes" 
   */
  public JavaFileGenerator(String templateName, Map options) {
    this.templateName = templateName;
    this.options = options;
  }
  private final String templateName;
  private final Map options; 
  
  private String currentLine;
  /**
   * Generate the output file.
   * @param out
   * @throws IOException
   */
  public void generate(PrintWriter out) throws IOException
  {
    InputStream is = getClass().getResourceAsStream(templateName);
    if (is == null)
      throw new IOException("Invalid template name: " + templateName);
    BufferedReader in = new BufferedReader(new InputStreamReader(is)); 
    process(in, out, false);
  }
  
  private String peekLine(BufferedReader in) throws IOException
  {
    if (currentLine == null)
      currentLine = in.readLine();
    
    return currentLine;
  }
  
  private String getLine(BufferedReader in) throws IOException
  {
    String line = currentLine;
    currentLine = null;
    
    if (line == null)
      in.readLine();
    
    return line;
  }
  
  private boolean evaluate(String condition)
  {
    condition = condition.trim();
    
    Object obj = options.get(condition);
    
    if (obj == null)
    {
      return condition.equalsIgnoreCase("true") || condition.equalsIgnoreCase("yes");
    }
    
    if (obj instanceof Boolean)
    {
      return ((Boolean)obj).booleanValue();
    }
    else if (obj instanceof String)
    {
      String string = ((String)obj).trim();
      return string.length() > 0 && !string.equalsIgnoreCase("false") && !string.equalsIgnoreCase("no");
    }
    
    return false;
  }
  
  private String substitute(String text) throws IOException
  {
    int startPos;
    
    if ( (startPos = text.indexOf("${")) == -1)
    {
      return text;
    }
    
    // Find matching "}".
    int braceDepth = 1;
    int endPos = startPos + 2;
    
    while ( endPos < text.length() && braceDepth > 0)
    {
      if (text.charAt(endPos) == "{")
        braceDepth++;
      else if (text.charAt(endPos) == "}")
        braceDepth--;
      
      endPos++;
    }
    
    if (braceDepth != 0)
      throw new IOException("Mismatched \"{}\" in template string: " + text); 
    
    final String variableExpression = text.substring(startPos + 2, endPos - 1);
    // Find the end of the variable name
    String value = null;
    
    for (int i = 0; i < variableExpression.length(); i++)
    {
      char ch = variableExpression.charAt(i);
      
      if (ch == ":" && i < variableExpression.length() - 1 && variableExpression.charAt(i+1) == "-" )
      {
        value = substituteWithDefault(variableExpression.substring(0, i), variableExpression.substring(i + 2));
        break;
      }
      else if (ch == "?")
      {
        value = substituteWithConditional(variableExpression.substring(0, i), variableExpression.substring(i + 1));
        break;
      }
      else if (ch != "_" && !Character.isJavaIdentifierPart(ch))
      {
        throw new IOException("Invalid variable in " + text);
      }
    }
    
    if (value == null)
    {
      value = substituteWithDefault(variableExpression, "");
    }
    
    return text.substring(0, startPos) + value + text.substring(endPos);
  }
  
  /**
   * @param substring
   * @param defaultValue
   * @return
   * @throws IOException 
   */
  private String substituteWithConditional(String variableName, String values) throws IOException
  {
    // Split values into true and false values.
    
    int pos = values.indexOf(":");
    if (pos == -1)
      throw new IOException("No ":" separator in " + values);
    
    if (evaluate(variableName))
      return substitute(values.substring(0, pos));
    else
      return substitute(values.substring(pos + 1));
  }
  /**
   * @param variableName
   * @param defaultValue
   * @return
   */
  private String substituteWithDefault(String variableName, String defaultValue) throws IOException
  {
    Object obj = options.get(variableName.trim());
    if (obj == null || obj.toString().length() == 0)
      return substitute(defaultValue);
    
    return obj.toString();
  }
  private void write(PrintWriter out, String text) throws IOException
  {
    while ( text.indexOf("${") != -1)
    {
      text = substitute(text);
    }
    
    out.println(text);
  }
  
  private void process(BufferedReader in, PrintWriter out, boolean ignoring)  throws IOException
  {
//    out.println("*** process ignore=" + ignoring + " : " + peekLine(in));
    while ( peekLine(in) != null)
    {
      if (peekLine(in).trim().startsWith("#if"))
      {
        String line = getLine(in).trim();
        final boolean condition = evaluate(line.substring(3).trim());
        
        process(in, out, ignoring || !condition);
        
        if (peekLine(in) != null && peekLine(in).trim().startsWith("#else"))
        {
          getLine(in);   // Discard the #else line
          process(in, out, ignoring || condition);
        }
        
        line = getLine(in);
        
        if (line == null)
          throw new IOException("Missing \"#fi\"");
        
        if (!line.trim().startsWith("#fi"))
          throw new IOException("Expected \"#fi\", got: " + line);
      }
      else if (peekLine(in).trim().startsWith("#")) 
      {
        break;
      }
      else
      {
        String line = getLine(in);
        if (!ignoring) write(out, line);
      }
    }
    
    out.flush();
  }
  
  public static void main(String[] args) throws Exception
  {
    Map map = new HashMap();
    map.put("falseArg", Boolean.FALSE);
    map.put("trueArg", Boolean.TRUE);
    map.put("stringValue", "someString");
    
    new JavaFileGenerator(args[0], map).generate(new PrintWriter(args[1]));
  }
}





Load a text file contents as a String.

   
/*
 * 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.
 */
import java.io.File;
import java.io.FileReader;
import java.io.IOException;

public class Main {

  /**
   * Load a text file contents as a <code>String<code>.
   * This method does not perform enconding conversions
   *
   * @param file The input file
   * @return The file contents as a <code>String</code>
   * @exception IOException IO Error
   */
  public static String deserializeString(File file)
  throws IOException {
      int len;
      char[] chr = new char[4096];
      final StringBuffer buffer = new StringBuffer();
      final FileReader reader = new FileReader(file);
      try {
          while ((len = reader.read(chr)) > 0) {
              buffer.append(chr, 0, len);
          }
      } finally {
          reader.close();
      }
      return buffer.toString();
  }
}





Load File As Text

     
/*
    GNU LESSER GENERAL PUBLIC LICENSE
    Copyright (C) 2006 The Lobo Project
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.
    This library 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
    Lesser General Public License for more details.
    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
    Contact info: lobochief@users.sourceforge.net
*/
/*
 * Created on Mar 19, 2005
 */
import java.io.*;
/**
 * @author J. H. S.
 */
public class IORoutines {
  public static final byte[] LINE_BREAK_BYTES = { (byte) 13, (byte) 10 }; 
  
  public static String loadAsText(InputStream in, String encoding) throws IOException {
    return loadAsText(in, encoding, 4096);
  }
  
  public static String loadAsText(InputStream in, String encoding, int bufferSize) throws IOException {
    InputStreamReader reader = new InputStreamReader(in, encoding);
      char[] buffer = new char[bufferSize];
      int offset = 0;
      for(;;) {
        int remain = buffer.length - offset;
        if(remain <= 0) {
          char[] newBuffer = new char[buffer.length * 2];
          System.arraycopy(buffer, 0, newBuffer, 0, offset);                    
          buffer = newBuffer;
          remain = buffer.length - offset;
        }
          int numRead = reader.read(buffer, offset, remain);
          if(numRead == -1) {
            break;
          }
        offset += numRead;
      }
      return new String(buffer, 0, offset);
  }
  
    public static byte[] load(File file) throws IOException {
        long fileLength = file.length();
        if(fileLength > Integer.MAX_VALUE) {
            throw new IOException("File "" + file.getName() + "" too big");
        }
        InputStream in = new FileInputStream(file);
        try {
          return loadExact(in, (int) fileLength);
        } finally {
            in.close();
        }
    }
    
    public static byte[] load(InputStream in) throws IOException {
        return load(in, 4096);
    }
    public static byte[] load(InputStream in, int initialBufferSize) throws IOException {
      if(initialBufferSize == 0) {
        initialBufferSize = 1;
      }
      byte[] buffer = new byte[initialBufferSize];
      int offset = 0;
      for(;;) {
        int remain = buffer.length - offset;
        if(remain <= 0) {
          int newSize = buffer.length * 2;
          byte[] newBuffer = new byte[newSize];
          System.arraycopy(buffer, 0, newBuffer, 0, offset);                    
          buffer = newBuffer;
          remain = buffer.length - offset;
        }
          int numRead = in.read(buffer, offset, remain);
          if(numRead == -1) {
            break;
          }
        offset += numRead;
      }
      if(offset < buffer.length) {
        byte[] newBuffer = new byte[offset];
        System.arraycopy(buffer, 0, newBuffer, 0, offset);                    
        buffer = newBuffer;
      }
      return buffer;
    }
    
    public static byte[] loadExact(InputStream in, int length) throws IOException {
      byte[] buffer = new byte[length];
      int offset = 0;
      for(;;) {
        int remain = length - offset;
        if(remain <= 0) {
          break;
        }
        int numRead = in.read(buffer, offset, remain);
        if(numRead == -1) {
          throw new IOException("Reached EOF, read " + offset + " expecting " + length);
        }
      offset += numRead;
      }
      return buffer;
    }
    public static boolean equalContent(File file, byte[] content) throws IOException {
      long length = file.length();
      if(length > Integer.MAX_VALUE) {
        throw new IOException("File "" + file + "" too big");
      }
      InputStream in = new FileInputStream(file);
      try {
        byte[] fileContent = loadExact(in, (int) length);
        return java.util.Arrays.equals(content, fileContent);
      } finally {
        in.close();
      }
    }
    
    public static void save(File file, byte[] content) throws IOException {
      FileOutputStream out = new FileOutputStream(file);
      try {
        out.write(content);
      } finally {
        out.close();
      }
    }
    
    /**
     * Reads line without buffering.
     */
    public static String readLine(InputStream in) throws IOException {
      int b;
      StringBuffer sb = null;
      OUTER:
      while((b = in.read()) != -1) {
        if(sb == null) {
          sb = new StringBuffer();
        }
        switch(b) {
          case (byte) "\n":
            break OUTER;
          case (byte) "\r":
            break;
          default:
            sb.append((char) b);
            break;
        }
      }
      return sb == null ? null : sb.toString();
    }
    
    public static void touch(File file) {
      file.setLastModified(System.currentTimeMillis());
    }
    
    public static void saveStrings(File file, java.util.Collection list) throws IOException {
      BufferedOutputStream bout = new BufferedOutputStream(new FileOutputStream(file));
      try {
        PrintWriter writer = new PrintWriter(bout);
        java.util.Iterator i = list.iterator();
        while(i.hasNext()) {
          String text = (String) i.next();
          writer.println(text);
        }
        writer.flush();
      } finally {
        bout.close();
      }
    }
    
    public static java.util.List loadStrings(File file) throws IOException {
      java.util.List list = new java.util.LinkedList();
      InputStream in = new FileInputStream(file);
      try {
        BufferedReader reader = new BufferedReader(new InputStreamReader(in));
        String line;
        while((line = reader.readLine()) != null) {
          list.add(line);
        }
        return list;
      } finally {
        in.close();
      }
    }
    
}





Load file content to List

     
/*
    GNU LESSER GENERAL PUBLIC LICENSE
    Copyright (C) 2006 The Lobo Project
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.
    This library 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
    Lesser General Public License for more details.
    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
    Contact info: lobochief@users.sourceforge.net
*/
/*
 * Created on Mar 19, 2005
 */
import java.io.*;
/**
 * @author J. H. S.
 */
public class IORoutines {
  public static final byte[] LINE_BREAK_BYTES = { (byte) 13, (byte) 10 }; 
  
  public static String loadAsText(InputStream in, String encoding) throws IOException {
    return loadAsText(in, encoding, 4096);
  }
  
  public static String loadAsText(InputStream in, String encoding, int bufferSize) throws IOException {
    InputStreamReader reader = new InputStreamReader(in, encoding);
      char[] buffer = new char[bufferSize];
      int offset = 0;
      for(;;) {
        int remain = buffer.length - offset;
        if(remain <= 0) {
          char[] newBuffer = new char[buffer.length * 2];
          System.arraycopy(buffer, 0, newBuffer, 0, offset);                    
          buffer = newBuffer;
          remain = buffer.length - offset;
        }
          int numRead = reader.read(buffer, offset, remain);
          if(numRead == -1) {
            break;
          }
        offset += numRead;
      }
      return new String(buffer, 0, offset);
  }
  
    public static byte[] load(File file) throws IOException {
        long fileLength = file.length();
        if(fileLength > Integer.MAX_VALUE) {
            throw new IOException("File "" + file.getName() + "" too big");
        }
        InputStream in = new FileInputStream(file);
        try {
          return loadExact(in, (int) fileLength);
        } finally {
            in.close();
        }
    }
    
    public static byte[] load(InputStream in) throws IOException {
        return load(in, 4096);
    }
    public static byte[] load(InputStream in, int initialBufferSize) throws IOException {
      if(initialBufferSize == 0) {
        initialBufferSize = 1;
      }
      byte[] buffer = new byte[initialBufferSize];
      int offset = 0;
      for(;;) {
        int remain = buffer.length - offset;
        if(remain <= 0) {
          int newSize = buffer.length * 2;
          byte[] newBuffer = new byte[newSize];
          System.arraycopy(buffer, 0, newBuffer, 0, offset);                    
          buffer = newBuffer;
          remain = buffer.length - offset;
        }
          int numRead = in.read(buffer, offset, remain);
          if(numRead == -1) {
            break;
          }
        offset += numRead;
      }
      if(offset < buffer.length) {
        byte[] newBuffer = new byte[offset];
        System.arraycopy(buffer, 0, newBuffer, 0, offset);                    
        buffer = newBuffer;
      }
      return buffer;
    }
    
    public static byte[] loadExact(InputStream in, int length) throws IOException {
      byte[] buffer = new byte[length];
      int offset = 0;
      for(;;) {
        int remain = length - offset;
        if(remain <= 0) {
          break;
        }
        int numRead = in.read(buffer, offset, remain);
        if(numRead == -1) {
          throw new IOException("Reached EOF, read " + offset + " expecting " + length);
        }
      offset += numRead;
      }
      return buffer;
    }
    public static boolean equalContent(File file, byte[] content) throws IOException {
      long length = file.length();
      if(length > Integer.MAX_VALUE) {
        throw new IOException("File "" + file + "" too big");
      }
      InputStream in = new FileInputStream(file);
      try {
        byte[] fileContent = loadExact(in, (int) length);
        return java.util.Arrays.equals(content, fileContent);
      } finally {
        in.close();
      }
    }
    
    public static void save(File file, byte[] content) throws IOException {
      FileOutputStream out = new FileOutputStream(file);
      try {
        out.write(content);
      } finally {
        out.close();
      }
    }
    
    /**
     * Reads line without buffering.
     */
    public static String readLine(InputStream in) throws IOException {
      int b;
      StringBuffer sb = null;
      OUTER:
      while((b = in.read()) != -1) {
        if(sb == null) {
          sb = new StringBuffer();
        }
        switch(b) {
          case (byte) "\n":
            break OUTER;
          case (byte) "\r":
            break;
          default:
            sb.append((char) b);
            break;
        }
      }
      return sb == null ? null : sb.toString();
    }
    
    public static void touch(File file) {
      file.setLastModified(System.currentTimeMillis());
    }
    
    public static void saveStrings(File file, java.util.Collection list) throws IOException {
      BufferedOutputStream bout = new BufferedOutputStream(new FileOutputStream(file));
      try {
        PrintWriter writer = new PrintWriter(bout);
        java.util.Iterator i = list.iterator();
        while(i.hasNext()) {
          String text = (String) i.next();
          writer.println(text);
        }
        writer.flush();
      } finally {
        bout.close();
      }
    }
    
    public static java.util.List loadStrings(File file) throws IOException {
      java.util.List list = new java.util.LinkedList();
      InputStream in = new FileInputStream(file);
      try {
        BufferedReader reader = new BufferedReader(new InputStreamReader(in));
        String line;
        while((line = reader.readLine()) != null) {
          list.add(line);
        }
        return list;
      } finally {
        in.close();
      }
    }
    
}





Load file line by line

     
/*
    GNU LESSER GENERAL PUBLIC LICENSE
    Copyright (C) 2006 The Lobo Project
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.
    This library 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
    Lesser General Public License for more details.
    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
    Contact info: lobochief@users.sourceforge.net
*/
/*
 * Created on Mar 19, 2005
 */
import java.io.*;
/**
 * @author J. H. S.
 */
public class IORoutines {
  public static final byte[] LINE_BREAK_BYTES = { (byte) 13, (byte) 10 }; 
  
  public static String loadAsText(InputStream in, String encoding) throws IOException {
    return loadAsText(in, encoding, 4096);
  }
  
  public static String loadAsText(InputStream in, String encoding, int bufferSize) throws IOException {
    InputStreamReader reader = new InputStreamReader(in, encoding);
      char[] buffer = new char[bufferSize];
      int offset = 0;
      for(;;) {
        int remain = buffer.length - offset;
        if(remain <= 0) {
          char[] newBuffer = new char[buffer.length * 2];
          System.arraycopy(buffer, 0, newBuffer, 0, offset);                    
          buffer = newBuffer;
          remain = buffer.length - offset;
        }
          int numRead = reader.read(buffer, offset, remain);
          if(numRead == -1) {
            break;
          }
        offset += numRead;
      }
      return new String(buffer, 0, offset);
  }
  
    public static byte[] load(File file) throws IOException {
        long fileLength = file.length();
        if(fileLength > Integer.MAX_VALUE) {
            throw new IOException("File "" + file.getName() + "" too big");
        }
        InputStream in = new FileInputStream(file);
        try {
          return loadExact(in, (int) fileLength);
        } finally {
            in.close();
        }
    }
    
    public static byte[] load(InputStream in) throws IOException {
        return load(in, 4096);
    }
    public static byte[] load(InputStream in, int initialBufferSize) throws IOException {
      if(initialBufferSize == 0) {
        initialBufferSize = 1;
      }
      byte[] buffer = new byte[initialBufferSize];
      int offset = 0;
      for(;;) {
        int remain = buffer.length - offset;
        if(remain <= 0) {
          int newSize = buffer.length * 2;
          byte[] newBuffer = new byte[newSize];
          System.arraycopy(buffer, 0, newBuffer, 0, offset);                    
          buffer = newBuffer;
          remain = buffer.length - offset;
        }
          int numRead = in.read(buffer, offset, remain);
          if(numRead == -1) {
            break;
          }
        offset += numRead;
      }
      if(offset < buffer.length) {
        byte[] newBuffer = new byte[offset];
        System.arraycopy(buffer, 0, newBuffer, 0, offset);                    
        buffer = newBuffer;
      }
      return buffer;
    }
    
    public static byte[] loadExact(InputStream in, int length) throws IOException {
      byte[] buffer = new byte[length];
      int offset = 0;
      for(;;) {
        int remain = length - offset;
        if(remain <= 0) {
          break;
        }
        int numRead = in.read(buffer, offset, remain);
        if(numRead == -1) {
          throw new IOException("Reached EOF, read " + offset + " expecting " + length);
        }
      offset += numRead;
      }
      return buffer;
    }
    public static boolean equalContent(File file, byte[] content) throws IOException {
      long length = file.length();
      if(length > Integer.MAX_VALUE) {
        throw new IOException("File "" + file + "" too big");
      }
      InputStream in = new FileInputStream(file);
      try {
        byte[] fileContent = loadExact(in, (int) length);
        return java.util.Arrays.equals(content, fileContent);
      } finally {
        in.close();
      }
    }
    
    public static void save(File file, byte[] content) throws IOException {
      FileOutputStream out = new FileOutputStream(file);
      try {
        out.write(content);
      } finally {
        out.close();
      }
    }
    
    /**
     * Reads line without buffering.
     */
    public static String readLine(InputStream in) throws IOException {
      int b;
      StringBuffer sb = null;
      OUTER:
      while((b = in.read()) != -1) {
        if(sb == null) {
          sb = new StringBuffer();
        }
        switch(b) {
          case (byte) "\n":
            break OUTER;
          case (byte) "\r":
            break;
          default:
            sb.append((char) b);
            break;
        }
      }
      return sb == null ? null : sb.toString();
    }
    
    public static void touch(File file) {
      file.setLastModified(System.currentTimeMillis());
    }
    
    public static void saveStrings(File file, java.util.Collection list) throws IOException {
      BufferedOutputStream bout = new BufferedOutputStream(new FileOutputStream(file));
      try {
        PrintWriter writer = new PrintWriter(bout);
        java.util.Iterator i = list.iterator();
        while(i.hasNext()) {
          String text = (String) i.next();
          writer.println(text);
        }
        writer.flush();
      } finally {
        bout.close();
      }
    }
    
    public static java.util.List loadStrings(File file) throws IOException {
      java.util.List list = new java.util.LinkedList();
      InputStream in = new FileInputStream(file);
      try {
        BufferedReader reader = new BufferedReader(new InputStreamReader(in));
        String line;
        while((line = reader.readLine()) != null) {
          list.add(line);
        }
        return list;
      } finally {
        in.close();
      }
    }
    
}





Read and return the entire contents of the supplied File.

 
/*
 * JBoss DNA (http://www.jboss.org/dna)
 * See the COPYRIGHT.txt file distributed with this work for information
 * regarding copyright ownership.  Some portions may be licensed
 * to Red Hat, Inc. under one or more contributor license agreements.
 * See the AUTHORS.txt file in the distribution for a full listing of 
 * individual contributors. 
 *
 * JBoss DNA is free software. Unless otherwise indicated, all code in JBoss DNA
 * is licensed to you under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * JBoss DNA 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.Reader;
/**
 * @author Randall Hauch
 */
public class Main {
  /**
   * Read and return the entire contents of the supplied {@link File}.
   * 
   * @param file the file containing the information to be read; may be null
   * @return the contents, or an empty string if the supplied reader is null
   * @throws IOException if there is an error reading the content
   */
  public static String read( File file ) throws IOException {
      if (file == null) return "";
      StringBuilder sb = new StringBuilder();
      boolean error = false;
      Reader reader = new FileReader(file);
      try {
          int numRead = 0;
          char[] buffer = new char[1024];
          while ((numRead = reader.read(buffer)) > -1) {
              sb.append(buffer, 0, numRead);
          }
      } catch (IOException e) {
          error = true; // this error should be thrown, even if there is an error closing reader
          throw e;
      } catch (RuntimeException e) {
          error = true; // this error should be thrown, even if there is an error closing reader
          throw e;
      } finally {
          try {
              reader.close();
          } catch (IOException e) {
              if (!error) throw e;
          }
      }
      return sb.toString();
  }
}





Searches case sensitively in a file

     
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FilenameFilter;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Iterator;
/*
 * IzPack - Copyright 2001-2008 Julien Ponge, All Rights Reserved.
 *
 * http://izpack.org/
 * http://izpack.codehaus.org/
 *
 * Copyright 2005 Marc Eppelmann
 *
 * Licensed 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.
 */

/**
 * Provides general global file utility methods
 *
 * @author marc.eppelmann
 */
class FileUtil
{
    //~ Constructors ***********************************************************************
    /**
     * Creates a new FileUtil object.
     */
    public FileUtil()
    {
    }
    //~ Methods ****************************************************************************
    /**
     * Gets the content from a File as StringArray List.
     *
     * @param fileName A file to read from.
     * @return List of individual line of the specified file. List may be empty but not
     *         null.
     * @throws IOException
     */
    public static ArrayList getFileContent(String fileName)
            throws IOException
    {
        ArrayList result = new ArrayList();
        File aFile = new File(fileName);
        if (!aFile.isFile())
        {
            //throw new IOException( fileName + " is not a regular File" );
            return result; // None
        }
        BufferedReader reader = null;
        try
        {
            reader = new BufferedReader(new FileReader(aFile));
        }
        catch (FileNotFoundException e1)
        {
            // TODO handle Exception
            e1.printStackTrace();
            return result;
        }
        String aLine = null;
        while ((aLine = reader.readLine()) != null)
        {
            result.add(aLine + "\n");
        }
        reader.close();
        return result;
    }
    /**
     * Searches case sensitively, and returns true if the given SearchString occurs in the
     * first File with the given Filename.
     *
     * @param aFileName     A files name
     * @param aSearchString the string search for
     * @return true if found in the file otherwise false
     */
    public static boolean fileContains(String aFileName, String aSearchString)
    {
        return (fileContains(aFileName, aSearchString, false));
    }
    /**
     * Tests if the given File contains the given Search String
     *
     * @param aFileName             A files name
     * @param aSearchString         the String to search for
     * @param caseInSensitiveSearch If false the Search is casesensitive
     * @return true if found in the file otherwise false
     */
    public static boolean fileContains(String aFileName, String aSearchString,
                                       boolean caseInSensitiveSearch)
    {
        boolean result = false;
        String searchString = caseInSensitiveSearch
                ? aSearchString.toLowerCase() : aSearchString;
        ArrayList fileContent = new ArrayList();
        try
        {
            fileContent = getFileContent(aFileName);
        }
        catch (IOException e)
        {
            // TODO handle Exception
            e.printStackTrace();
        }
        Iterator linesIter = fileContent.iterator();
        while (linesIter.hasNext())
        {
            String currentline = (String) linesIter.next();
            if (caseInSensitiveSearch)
            {
                currentline = currentline.toLowerCase();
            }
            if (currentline.indexOf(searchString) > -1)
            {
                result = true;
                break;
            }
        }
        return result;
    }
    /**
     * Gets file date and time.
     *
     * @param url The URL of the file for which date and time will be returned.
     * @return Returns long value which is the date and time of the file. If any error
     *         occures returns -1 (=no file date and time available).
     */
    public static long getFileDateTime(URL url)
    {
        if (url == null)
        {
            return -1;
        }
        String fileName = url.getFile();
        if (fileName.charAt(0) == "/" || fileName.charAt(0) == "\\")
        {
            fileName = fileName.substring(1, fileName.length());
        }
        try
        {
            File file = new File(fileName);
            // File name must be a file or a directory.
            if (!file.isDirectory() && !file.isFile())
            {
                return -1;
            }
            return file.lastModified();
        }
        catch (java.lang.Exception e)
        {   // Trap all Exception based exceptions and return -1.
            return -1;
        }
    }
    public static String[] getFileNames(String dirPath) throws Exception
    {
        return getFileNames(dirPath, null);
    }
    public static String[] getFileNames(String dirPath, FilenameFilter fileNameFilter) throws Exception
    {
        String fileNames[] = null;
        File dir = new File(dirPath);
        if (dir.isDirectory())
        {
            if (fileNameFilter != null)
            {
                fileNames = dir.list(fileNameFilter);
            }
            else
            {
                fileNames = dir.list();
            }
        }
        return fileNames;
    }
    /**
     * Test main
     *
     * @param args
     */
    public static void main(String[] args)
    {
    }
}





To Hex String and char

     
/* jcifs smb client library in Java
 * Copyright (C) 2000  "Michael B. Allen" <jcifs at samba dot org>
 *                     "Christopher R. Hertel" <jcifs at samba dot org>
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

import java.io.OutputStream;
import java.io.PrintStream;
/**
 */
public class Hexdump {
    private static final String NL = System.getProperty( "line.separator" );
    private static final int NL_LENGTH = NL.length();
    private static final char[] SPACE_CHARS = {
        " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ",
        " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ",
        " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " "
    };
    public static final char[] HEX_DIGITS = { 
        "0", "1", "2", "3", "4", "5",
        "6", "7", "8", "9", "A", "B",
        "C", "D", "E", "F"
    };
/** 
 * Generate "hexdump" output of the buffer at src like the following:
 *
 * <p><blockquote><pre>
 * 00000: 04 d2 29 00 00 01 00 00 00 00 00 01 20 45 47 46  |..)......... EGF|
 * 00010: 43 45 46 45 45 43 41 43 41 43 41 43 41 43 41 43  |CEFEECACACACACAC|
 * 00020: 41 43 41 43 41 43 41 43 41 43 41 41 44 00 00 20  |ACACACACACAAD.. |
 * 00030: 00 01 c0 0c 00 20 00 01 00 00 00 00 00 06 20 00  |..... ........ .|
 * 00040: ac 22 22 e1                                      |."".            |
 * </blockquote></pre>
 */
    public static void hexdump( PrintStream ps, byte[] src, int srcIndex, int length ) {
        if( length == 0 ) {
            return;
        }
        int s = length % 16;
        int r = ( s == 0 ) ? length / 16 : length / 16 + 1;
        char[] c = new char[r * (74 + NL_LENGTH)];
        char[] d = new char[16];
        int i;
        int si = 0;
        int ci = 0;
        do {
            toHexChars( si, c, ci, 5 );
            ci += 5;
            c[ci++] = ":";
            do {
                if( si == length ) {
                    int n = 16 - s;
                    System.arraycopy( SPACE_CHARS, 0, c, ci, n * 3 );
                    ci += n * 3;
                    System.arraycopy( SPACE_CHARS, 0, d, s, n );
                    break;
                }
                c[ci++] = " ";
                i = src[srcIndex + si] & 0xFF;
                toHexChars( i, c, ci, 2 );
                ci += 2; 
                if( i < 0 || Character.isISOControl( (char)i )) {
                    d[si % 16] = ".";
                } else {
                    d[si % 16] = (char)i;
                }
            } while(( ++si % 16 ) != 0 );
            c[ci++] = " ";
            c[ci++] = " ";
            c[ci++] = "|";
            System.arraycopy( d, 0, c, ci, 16 );
            ci += 16;
            c[ci++] = "|";
            NL.getChars( 0, NL_LENGTH, c, ci );
            ci += NL_LENGTH;
        } while( si < length );
        ps.println( c );
    }
/** 
 * This is an alternative to the <code>java.lang.Integer.toHexString</cod>
 * method. It is an efficient relative that also will pad the left side so
 * that the result is <code>size</code> digits.
 */ 
    public static String toHexString( int val, int size ) {
        char[] c = new char[size];
        toHexChars( val, c, 0, size );
        return new String( c );
    }
    public static String toHexString( long val, int size ) {
        char[] c = new char[size];
        toHexChars( val, c, 0, size );
        return new String( c );
    }
    public static String toHexString( byte[] src, int srcIndex, int size ) {
        char[] c = new char[size];
        size = ( size % 2 == 0 ) ? size / 2 : size / 2 + 1;
        for( int i = 0, j = 0; i < size; i++ ) {
            c[j++] = HEX_DIGITS[(src[i] >> 4 ) & 0x0F];
            if( j == c.length ) {
                break;
            }
            c[j++] = HEX_DIGITS[src[i] & 0x0F];
        }
        return new String( c );
    }
/** 
 * This is the same as {@link jcifs.util.Hexdump#toHexString(int val, int
 * size)} but provides a more practical form when trying to avoid {@link
 * java.lang.String} concatenation and {@link java.lang.StringBuffer}.
 */ 
    public static void toHexChars( int val, char dst[], int dstIndex, int size ) {
        while( size > 0 ) {
            int i = dstIndex + size - 1;
            if( i < dst.length ) {
                dst[i] = HEX_DIGITS[val & 0x000F];
            }
            if( val != 0 ) {
                val >>>= 4;
            }
            size--;
        }
    }
    public static void toHexChars( long val, char dst[], int dstIndex, int size ) {
        while( size > 0 ) {
            dst[dstIndex + size - 1] = HEX_DIGITS[(int)( val & 0x000FL )];
            if( val != 0 ) {
                val >>>= 4;
            }
            size--;
        }
    }
}





Writing delimited text data to a file or a stream

     
/*
 * Java CSV is a stream based library for reading and writing
 * CSV and other delimited data.
 *   
 * Copyright (C) Bruce Dunwiddie bruce@csvreader.ru
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 */
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.Writer;
import java.nio.charset.Charset;
/**
 * A stream based writer for writing delimited text data to a file or a stream.
 */
public class CsvWriter {
  private PrintWriter outputStream = null;
  private String fileName = null;
  private boolean firstColumn = true;
  private boolean useCustomRecordDelimiter = false;
  private Charset charset = null;
  // this holds all the values for switches that the user is allowed to set
  private UserSettings userSettings = new UserSettings();
  private boolean initialized = false;
  private boolean closed = false;
  /**
   * Double up the text qualifier to represent an occurance of the text
   * qualifier.
   */
  public static final int ESCAPE_MODE_DOUBLED = 1;
  /**
   * Use a backslash character before the text qualifier to represent an
   * occurance of the text qualifier.
   */
  public static final int ESCAPE_MODE_BACKSLASH = 2;
  /**
   * Creates a {@link com.csvreader.CsvWriter CsvWriter} object using a file
   * as the data destination.
   * 
   * @param fileName
   *            The path to the file to output the data.
   * @param delimiter
   *            The character to use as the column delimiter.
   * @param charset
   *            The {@link java.nio.charset.Charset Charset} to use while
   *            writing the data.
   */
  public CsvWriter(String fileName, char delimiter, Charset charset) {
    if (fileName == null) {
      throw new IllegalArgumentException("Parameter fileName can not be null.");
    }
    if (charset == null) {
      throw new IllegalArgumentException("Parameter charset can not be null.");
    }
    this.fileName = fileName;
    userSettings.Delimiter = delimiter;
    this.charset = charset;
  }
  /**
   * Creates a {@link com.csvreader.CsvWriter CsvWriter} object using a file
   * as the data destination.&nbsp;Uses a comma as the column delimiter and
   * ISO-8859-1 as the {@link java.nio.charset.Charset Charset}.
   * 
   * @param fileName
   *            The path to the file to output the data.
   */
  public CsvWriter(String fileName) {
    this(fileName, Letters.ruMA, Charset.forName("ISO-8859-1"));
  }
  /**
   * Creates a {@link com.csvreader.CsvWriter CsvWriter} object using a Writer
   * to write data to.
   * 
   * @param outputStream
   *            The stream to write the column delimited data to.
   * @param delimiter
   *            The character to use as the column delimiter.
   */
  public CsvWriter(Writer outputStream, char delimiter) {
    if (outputStream == null) {
      throw new IllegalArgumentException("Parameter outputStream can not be null.");
    }
    this.outputStream = new PrintWriter(outputStream);
    userSettings.Delimiter = delimiter;
    initialized = true;
  }
  /**
   * Creates a {@link com.csvreader.CsvWriter CsvWriter} object using an
   * OutputStream to write data to.
   * 
   * @param outputStream
   *            The stream to write the column delimited data to.
   * @param delimiter
   *            The character to use as the column delimiter.
   * @param charset
   *            The {@link java.nio.charset.Charset Charset} to use while
   *            writing the data.
   */
  public CsvWriter(OutputStream outputStream, char delimiter, Charset charset) {
    this(new OutputStreamWriter(outputStream, charset), delimiter);
  }
  /**
   * Gets the character being used as the column delimiter.
   * 
   * @return The character being used as the column delimiter.
   */
  public char getDelimiter() {
    return userSettings.Delimiter;
  }
  /**
   * Sets the character to use as the column delimiter.
   * 
   * @param delimiter
   *            The character to use as the column delimiter.
   */
  public void setDelimiter(char delimiter) {
    userSettings.Delimiter = delimiter;
  }
  public char getRecordDelimiter() {
    return userSettings.RecordDelimiter;
  }
  /**
   * Sets the character to use as the record delimiter.
   * 
   * @param recordDelimiter
   *            The character to use as the record delimiter. Default is
   *            combination of standard end of line characters for Windows,
   *            Unix, or Mac.
   */
  public void setRecordDelimiter(char recordDelimiter) {
    useCustomRecordDelimiter = true;
    userSettings.RecordDelimiter = recordDelimiter;
  }
  /**
   * Gets the character to use as a text qualifier in the data.
   * 
   * @return The character to use as a text qualifier in the data.
   */
  public char getTextQualifier() {
    return userSettings.TextQualifier;
  }
  /**
   * Sets the character to use as a text qualifier in the data.
   * 
   * @param textQualifier
   *            The character to use as a text qualifier in the data.
   */
  public void setTextQualifier(char textQualifier) {
    userSettings.TextQualifier = textQualifier;
  }
  /**
   * Whether text qualifiers will be used while writing data or not.
   * 
   * @return Whether text qualifiers will be used while writing data or not.
   */
  public boolean getUseTextQualifier() {
    return userSettings.UseTextQualifier;
  }
  /**
   * Sets whether text qualifiers will be used while writing data or not.
   * 
   * @param useTextQualifier
   *            Whether to use a text qualifier while writing data or not.
   */
  public void setUseTextQualifier(boolean useTextQualifier) {
    userSettings.UseTextQualifier = useTextQualifier;
  }
  public int getEscapeMode() {
    return userSettings.EscapeMode;
  }
  public void setEscapeMode(int escapeMode) {
    userSettings.EscapeMode = escapeMode;
  }
  public void setComment(char comment) {
    userSettings.rument = comment;
  }
  public char getComment() {
    return userSettings.rument;
  }
  /**
   * Whether fields will be surrounded by the text qualifier even if the
   * qualifier is not necessarily needed to escape this field.
   * 
   * @return Whether fields will be forced to be qualified or not.
   */
  public boolean getForceQualifier() {
    return userSettings.ForceQualifier;
  }
  /**
   * Use this to force all fields to be surrounded by the text qualifier even
   * if the qualifier is not necessarily needed to escape this field. Default
   * is false.
   * 
   * @param forceQualifier
   *            Whether to force the fields to be qualified or not.
   */
  public void setForceQualifier(boolean forceQualifier) {
    userSettings.ForceQualifier = forceQualifier;
  }
  /**
   * Writes another column of data to this record.
   * 
   * @param content
   *            The data for the new column.
   * @param preserveSpaces
   *            Whether to preserve leading and trailing whitespace in this
   *            column of data.
   * @exception IOException
   *                Thrown if an error occurs while writing data to the
   *                destination stream.
   */
  public void write(String content, boolean preserveSpaces)
      throws IOException {
    checkClosed();
    checkInit();
    if (content == null) {
      content = "";
    }
    if (!firstColumn) {
      outputStream.write(userSettings.Delimiter);
    }
    boolean textQualify = userSettings.ForceQualifier;
    if (!preserveSpaces && content.length() > 0) {
      content = content.trim();
    }
    if (!textQualify
        && userSettings.UseTextQualifier
        && (content.indexOf(userSettings.TextQualifier) > -1
            || content.indexOf(userSettings.Delimiter) > -1
            || (!useCustomRecordDelimiter && (content
                .indexOf(Letters.LF) > -1 || content
                .indexOf(Letters.CR) > -1))
            || (useCustomRecordDelimiter && content
                .indexOf(userSettings.RecordDelimiter) > -1)
            || (firstColumn && content.length() > 0 && content
                .charAt(0) == userSettings.rument) ||
        // check for empty first column, which if on its own line must
        // be qualified or the line will be skipped
        (firstColumn && content.length() == 0))) {
      textQualify = true;
    }
    if (userSettings.UseTextQualifier && !textQualify
        && content.length() > 0 && preserveSpaces) {
      char firstLetter = content.charAt(0);
      if (firstLetter == Letters.SPACE || firstLetter == Letters.TAB) {
        textQualify = true;
      }
      if (!textQualify && content.length() > 1) {
        char lastLetter = content.charAt(content.length() - 1);
        if (lastLetter == Letters.SPACE || lastLetter == Letters.TAB) {
          textQualify = true;
        }
      }
    }
    if (textQualify) {
      outputStream.write(userSettings.TextQualifier);
      if (userSettings.EscapeMode == ESCAPE_MODE_BACKSLASH) {
        content = replace(content, "" + Letters.BACKSLASH, ""
            + Letters.BACKSLASH + Letters.BACKSLASH);
        content = replace(content, "" + userSettings.TextQualifier, ""
            + Letters.BACKSLASH + userSettings.TextQualifier);
      } else {
        content = replace(content, "" + userSettings.TextQualifier, ""
            + userSettings.TextQualifier
            + userSettings.TextQualifier);
      }
    } else if (userSettings.EscapeMode == ESCAPE_MODE_BACKSLASH) {
      content = replace(content, "" + Letters.BACKSLASH, ""
          + Letters.BACKSLASH + Letters.BACKSLASH);
      content = replace(content, "" + userSettings.Delimiter, ""
          + Letters.BACKSLASH + userSettings.Delimiter);
      if (useCustomRecordDelimiter) {
        content = replace(content, "" + userSettings.RecordDelimiter,
            "" + Letters.BACKSLASH + userSettings.RecordDelimiter);
      } else {
        content = replace(content, "" + Letters.CR, ""
            + Letters.BACKSLASH + Letters.CR);
        content = replace(content, "" + Letters.LF, ""
            + Letters.BACKSLASH + Letters.LF);
      }
      if (firstColumn && content.length() > 0
          && content.charAt(0) == userSettings.rument) {
        if (content.length() > 1) {
          content = "" + Letters.BACKSLASH + userSettings.rument
              + content.substring(1);
        } else {
          content = "" + Letters.BACKSLASH + userSettings.rument;
        }
      }
    }
    outputStream.write(content);
    if (textQualify) {
      outputStream.write(userSettings.TextQualifier);
    }
    firstColumn = false;
  }
  /**
   * Writes another column of data to this record.&nbsp;Does not preserve
   * leading and trailing whitespace in this column of data.
   * 
   * @param content
   *            The data for the new column.
   * @exception IOException
   *                Thrown if an error occurs while writing data to the
   *                destination stream.
   */
  public void write(String content) throws IOException {
    write(content, false);
  }
  public void writeComment(String commentText) throws IOException {
    checkClosed();
    checkInit();
    outputStream.write(userSettings.rument);
    outputStream.write(commentText);
    if (useCustomRecordDelimiter) {
      outputStream.write(userSettings.RecordDelimiter);
    } else {
      outputStream.println();
    }
    firstColumn = true;
  }
  /**
   * Writes a new record using the passed in array of values.
   * 
   * @param values
   *            Values to be written.
   * 
   * @param preserveSpaces
   *            Whether to preserver leading and trailing spaces in columns
   *            while writing out to the record or not.
   * 
   * @throws IOException
   *             Thrown if an error occurs while writing data to the
   *             destination stream.
   */
  public void writeRecord(String[] values, boolean preserveSpaces)
      throws IOException {
    if (values != null && values.length > 0) {
      for (int i = 0; i < values.length; i++) {
        write(values[i], preserveSpaces);
      }
      endRecord();
    }
  }
  /**
   * Writes a new record using the passed in array of values.
   * 
   * @param values
   *            Values to be written.
   * 
   * @throws IOException
   *             Thrown if an error occurs while writing data to the
   *             destination stream.
   */
  public void writeRecord(String[] values) throws IOException {
    writeRecord(values, false);
  }
  /**
   * Ends the current record by sending the record delimiter.
   * 
   * @exception IOException
   *                Thrown if an error occurs while writing data to the
   *                destination stream.
   */
  public void endRecord() throws IOException {
    checkClosed();
    checkInit();
    if (useCustomRecordDelimiter) {
      outputStream.write(userSettings.RecordDelimiter);
    } else {
      outputStream.println();
    }
    firstColumn = true;
  }
  /**
   * 
   */
  private void checkInit() throws IOException {
    if (!initialized) {
      if (fileName != null) {
        outputStream = new PrintWriter(new OutputStreamWriter(
            new FileOutputStream(fileName), charset));
      }
      initialized = true;
    }
  }
  /**
   * Clears all buffers for the current writer and causes any buffered data to
   * be written to the underlying device.
   */
  public void flush() {
    outputStream.flush();
  }
  /**
   * Closes and releases all related resources.
   */
  public void close() {
    if (!closed) {
      close(true);
      closed = true;
    }
  }
  /**
   * 
   */
  private void close(boolean closing) {
    if (!closed) {
      if (closing) {
        charset = null;
      }
      try {
        if (initialized) {
          outputStream.close();
        }
      } catch (Exception e) {
        // just eat the exception
      }
      outputStream = null;
      closed = true;
    }
  }
  /**
   * 
   */
  private void checkClosed() throws IOException {
    if (closed) {
      throw new IOException(
      "This instance of the CsvWriter class has already been closed.");
    }
  }
  /**
   * 
   */
  protected void finalize() {
    close(false);
  }
  private class Letters {
    public static final char LF = "\n";
    public static final char CR = "\r";
    public static final char QUOTE = """;
    public static final char COMMA = ",";
    public static final char SPACE = " ";
    public static final char TAB = "\t";
    public static final char POUND = "#";
    public static final char BACKSLASH = "\\";
    public static final char NULL = "\0";
  }
  private class UserSettings {
    // having these as publicly accessible members will prevent
    // the overhead of the method call that exists on properties
    public char TextQualifier;
    public boolean UseTextQualifier;
    public char Delimiter;
    public char RecordDelimiter;
    public char Comment;
    public int EscapeMode;
    public boolean ForceQualifier;
    public UserSettings() {
      TextQualifier = Letters.QUOTE;
      UseTextQualifier = true;
      Delimiter = Letters.ruMA;
      RecordDelimiter = Letters.NULL;
      Comment = Letters.POUND;
      EscapeMode = ESCAPE_MODE_DOUBLED;
      ForceQualifier = false;
    }
  }
  public static String replace(String original, String pattern, String replace) {
    final int len = pattern.length();
    int found = original.indexOf(pattern);
    if (found > -1) {
      StringBuffer sb = new StringBuffer();
      int start = 0;
      while (found != -1) {
        sb.append(original.substring(start, found));
        sb.append(replace);
        start = found + len;
        found = original.indexOf(pattern, start);
      }
      sb.append(original.substring(start));
      return sb.toString();
    } else {
      return original;
    }
  }
}