Java/GWT/Progress Bar

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GWT progress bar

   <source lang="java">

/* 

* Copyright 2006 Robert Hanson <iamroberthanson AT gmail.ru>
* 
* 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.
*/

package com.jexp.gwt.client; import com.google.gwt.user.client.*; import com.google.gwt.user.client.ui.*; import com.google.gwt.core.client.*; public class GWTClient implements EntryPoint{ 

 public void onModuleLoad() {
 final ProgressBar progressBar = new ProgressBar(20
            ,ProgressBar.SHOW_TIME_REMAINING
             +ProgressBar.SHOW_TEXT);
 progressBar.setText("Doing something...");
 RootPanel.get().add(progressBar);
 Timer t = new Timer() {
   public void run() {
     int progress = progressBar.getProgress()+4;
     if (progress>100) cancel();
     progressBar.setProgress(progress);
   }
 };
 t.scheduleRepeating(1000);
 }

} /**

*

A simple progress bar that uses table elements to show progress * and with a basic time remaining calculation built in. * * <P>You can optionally display some text above the progress bar * and/or display time remaining underneath the progress bar. To * control the display of those features, set the options in the * constructor as shown in the following usage example: * * 

 *  final ProgressBar progressBar = new ProgressBar(20
 *             ,ProgressBar.SHOW_TIME_REMAINING
 *              +ProgressBar.SHOW_TEXT);
 *  progressBar.setText("Doing something...");
 *  RootPanel.get().add(progressBar);
 *  Timer t = new Timer() {
 *    public void run() {
 *      int progress = progressBar.getProgress()+4;
 *      if (progress>100) cancel();
 *      progressBar.setProgress(progress);
 *    }
 *  };
 *  t.scheduleRepeating(1000);
 * 
*
* <P>How the time remaining is displayed can be controlled by setting the 
* relevant messages using the language of your choice.
* 
* <P>The default setting for the messages are as follows:
*
* 
 *    setSecondsMessage("Time remaining: {0} Seconds");
 *    setMinutesMessage("Time remaining: {0} Minutes");
 *    setHoursMessage("Time remaining: {0} Hours");
 * 
*
* <P>To reset the time remaining/set the start time, simply set the 
* progress to zero.
* 
* <P>Some basic CSS styling is available to control the text, border around the
* progress bar itself and the colour of the progress bar elements.
*
* 
 * .progressbar-text {
 *     font-weight: bold;
 * }
 * 
 * .progressbar-remaining {
 *     font-size: 12px;
 *     font-style: italic;
 * }
 * 
 * .progressbar-outer {
 *     border: 1px solid black;
 * }
 * 
 * .progressbar-inner {
 *     border: 1px solid black;
 *     margin: 1px;
 * }
 * 
 * .progressbar-bar {
 *     width: 5px;
 *     height: 15px;
 *     margin: 1px;
 * }
 * 
 * .progressbar-fullbar {
 *     background: blue;
 * }
 * 
 * .progressbar-blankbar {
 *     background: #eee;
 * }
 *
*
* <P>You can take advantage of the default style by adding the
* following to the head of your HTML page. 
* 
* <P><link rel="stylesheet" type="text/css" href="style/gwl-progressBar.css">
*
* <P>This style sheet also has two additional styles which you can use
* by adding the stye name to the widget.  You can use either one of
* these, or use both combined.
*
* 
 *  ProgressBar progressBar = new ProgressBar(20);
 *  progressBar.addStyleName("progressbar-solid");
 *  progressBar.addStyleName("progressbar-noborder");
 * 
* 
* @author Bjarne Matzen - Bjarne[dot]Matzen[at]gmail[dot]com
*/

class ProgressBar extends VerticalPanel { 

 /**
  * Option to show text label above progress bar
  */
 public static final int SHOW_TEXT = 2;
 
 /**
  * Option to show time remaining
  */
 public static final int SHOW_TIME_REMAINING = 1;
 /**
  * The time the progress bar was started
  */
 private long startTime = System.currentTimeMillis();
 
 /**
  * The number of bar elements to show
  */
 private int elements = 20;
 
 /**
  * Time element text
  */
 private String secondsMessage = "Time remaining: {0} Seconds";
 private String minutesMessage = "Time remaining: {0} Minutes";
 private String hoursMessage = "Time remaining: {0} Hours";
 
 /**
  * Current progress (as a percentage)
  */
 private int progress = 0;
 
 /**
  * This is the frame around the progress bar
  */
 private FlexTable barFrame = new FlexTable();
 
 /**
  * This is the grid used to show the elements
  */
 private Grid elementGrid;
 
 /**
  * This is the current text label below the progress bar
  */
 private Label remainLabel = new Label();
 /**
  * This is the current text label above the progress bar
  */
 private Label textLabel = new Label();
 
 /** 
  * internal flags for options
  */
 private boolean showRemaining = false;
 private boolean showText = false;
 
 /**
  * Base constructor for this widget
  * 
  * @param elements The number of elements (bars) to show on the progress bar
  * @param options The display options for the progress bar
  */
 public ProgressBar (int elements, int options)
   {
       // Read the options and set convenience variables
       if ((options & SHOW_TIME_REMAINING) == SHOW_TIME_REMAINING) showRemaining = true;
       if ((options & SHOW_TEXT) == SHOW_TEXT) showText = true;
   
   // Set element count
   this.elements = elements;
   
   // Styling
   remainLabel.setStyleName("progressbar-remaining");
   textLabel.setStyleName("progressbar-text");
   
   // Initialize the progress elements
   elementGrid = new Grid(1, elements);
       elementGrid.setStyleName("progressbar-inner");
       elementGrid.setCellPadding(0);
       elementGrid.setCellSpacing(0);
       
       for (int loop = 0; loop < elements; loop++) {
           Grid elm = new Grid(1, 1);
           //elm.setHTML(0, 0, " ");
           elm.setHTML(0, 0, "");
           elm.setStyleName("progressbar-blankbar");
           elm.addStyleName("progressbar-bar");
           elementGrid.setWidget(0, loop, elm);
   }
   
   // Create the container around the elements
   Grid containerGrid = new Grid(1,1);
       containerGrid.setCellPadding(0);
       containerGrid.setCellSpacing(0);
   containerGrid.setWidget(0, 0, elementGrid);
   containerGrid.setStyleName("progressbar-outer");
     //containerGrid.setBorderWidth(1);
     
     // Set up the surrounding flex table based on the options
     int row = 0;
       if (showText) barFrame.setWidget(row++, 0, textLabel);
       barFrame.setWidget(row++, 0, containerGrid);
       if (showRemaining) barFrame.setWidget(row++, 0, remainLabel);
   barFrame.setWidth("100%");
   
   // Add the frame to the panel
   this.add(barFrame);
   
   // Initialize progress bar
   setProgress(0);
 }
 /**
  * Constructor without options
  * 
  * @param elements The number of elements (bars) to show on the progress bar
  */
 public ProgressBar (int elements)
   {
       this(elements, 0);
   }
 
 /**
  * Set the current progress as a percentage
  * 
  * @param percentage Set current percentage for the progress bar
  */
 public void setProgress (int percentage)
   {
   // Make sure we are error-tolerant
   if (percentage > 100) percentage = 100;
       if (percentage < 0) percentage = 0;
   
   // Set the internal variable
   progress = percentage;
   
   // Update the elements in the progress grid to
       // reflect the status
       int completed = elements * percentage / 100;
       for (int loop = 0; loop < elements; loop++) {
           Grid elm = (Grid) elementGrid.getWidget(0, loop);
           if (loop < completed) {
               elm.setStyleName("progressbar-fullbar");
               elm.addStyleName("progressbar-bar");
           }
           else {
               elm.setStyleName("progressbar-blankbar");
               elm.addStyleName("progressbar-bar");
           }
       }
   
   if (percentage > 0) {
           // Calculate the new time remaining
           long soFar = (System.currentTimeMillis() - startTime) / 1000;
           long remaining = soFar * (100 - percentage) / percentage;
           // Select the best UOM
           String remainText = secondsMessage;
           if (remaining > 120) {
               remaining = remaining / 60;
               remainText = minutesMessage;
               if (remaining > 120) {
                   remaining = remaining / 60;
                   remainText = hoursMessage;
               }
           }
           // Locate the position to insert out time remaining
           int pos = remainText.indexOf("{0}");
           if (pos >= 0) {
               String trail = "";
               if (pos + 3 < remainText.length()) trail = remainText.substring(pos + 3);
               remainText = remainText.substring(0, pos) + remaining + trail;
           }
           // Set the label
           remainLabel.setText(remainText);
       }
       else {
           // If progress is 0, reset the start time
           startTime = System.currentTimeMillis();
       }
 }
 /**
  * Get the current progress as a percentage
  * 
  * @return Current percentage for the progress bar
  */
 public int getProgress ()
   {
       return (progress);
   }
 /**
  * Get the text displayed above the progress bar
  * 
  * @return the text
  */
 public String getText ()
   {
       return this.textLabel.getText();
   }
 /**
  * Set the text displayed above the progress bar
  * 
  * @param text the text to set
  */
 public void setText (String text)
   {
       this.textLabel.setText(text);
   }
 /**
  * Get the message used to format the time remaining text
  * for hours
  * 
  * @return the hours message
  */
 public String getHoursMessage ()
   {
       return hoursMessage;
   }
 /**
  * Set the message used to format the time remaining text
  * below the progress bar. There are 3 messages used for
  * hours, minutes and seconds respectively.
  * 
  * The message must contain a placeholder for the value. The
  * placeholder must be {0}. For example, the following is
  * a valid message:
  * 
  *     "Hours remaining: {0}"
  * 
  * @param hoursMessage the hours message to set
  */
 public void setHoursMessage (String hoursMessage)
   {
       this.hoursMessage = hoursMessage;
   }
 /**
  * Get the message used to format the time remaining text
  * for minutes
  * 
  * @return the minutesMessage
  */
 public String getMinutesMessage ()
   {
       return minutesMessage;
   }
 /**
  * Set the message used to format the time remaining text
  * below the progress bar. There are 3 messages used for
  * hours, minutes and seconds respectively.
  * 
  * The message must contain a placeholder for the value. The
  * placeholder must be {0}. For example, the following is
  * a valid message:
  * 
  *     "Minutes remaining: {0}"
  * 
  * @param minutesMessage the minutes message to set
  */
 public void setMinutesMessage (String minutesMessage)
   {
       this.minutesMessage = minutesMessage;
   }
 /**
  * Get the message used to format the time remaining text
  * for seconds
  * 
  * @return the secondsMessage
  */
 public String getSecondsMessage ()
   {
       return secondsMessage;
   }
 /**
  * Set the message used to format the time remaining text
  * below the progress bar. There are 3 messages used for
  * hours, minutes and seconds respectively.
  * 
  * The message must contain a placeholder for the value. The
  * placeholder must be {0}. For example, the following is
  * a valid message:
  * 
  *     "Seconds remaining: {0}"
  * 
  * @param secondsMessage the secondsMessage to set
  */
 public void setSecondsMessage (String secondsMessage)
   {
       this.secondsMessage = secondsMessage;
   }

} 


      </source>

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