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  1. JDK
  2. JDK-4484185

ProgressMonitor popup won't back up, revisited

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    • Subcomponent:
    • Resolved In Build:
      b74
    • CPU:
      generic
    • OS:
      generic

      Description

      Name: bsC130419 Date: 07/25/2001


      java version "1.3.1"
      Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.1-b24)
      Java HotSpot(TM) Client VM (build 1.3.1-b24, mixed mode)

        To reproduce this problem, use a ProgressMonitor. Give it a long task so that
      the progress bar pops up. If at some point you call setProgress() with a value
      that is smaller than the largest value that has been set so far, the progress
      bar does not back up to reflect this.

        To demonstrate the problem, run the ProgressMonitorDemo with this code:
      http://java.sun.com/docs/books/tutorial/uiswing/components/example-swing/Progres
      sMonitorDemo.java
      http://java.sun.com/docs/books/tutorial/uiswing/components/example-swing/SwingWo
      rker.java

      but in place of the LongTask code provided in the tutorial example:
      http://java.sun.com/docs/books/tutorial/uiswing/components/example-swing/LongTas
      k.java

      Use this code for LongTask:
      /** Uses a SwingWorker to perform a time-consuming (and utterly fake) task. */

      public class LongTask {
          private int lengthOfTask;
          private int current = 500;
          private String statMessage;

          LongTask() {
              //Compute length of task...
              //In a real program, this would figure out
              //the number of bytes to read or whatever.
              lengthOfTask = 1000;
          }

          /**
           * Called from ProgressBarDemo to start the task.
           */
          void go() {
              current = 0;
              final SwingWorker worker = new SwingWorker() {
                  public Object construct() {
                      return new ActualTask();
                  }
              };
              worker.start();
          }

          /**
           * Called from ProgressBarDemo to find out how much work needs
           * to be done.
           */
          int getLengthOfTask() {
              return lengthOfTask;
          }

          /**
           * Called from ProgressBarDemo to find out how much has been done.
           */
          int getCurrent() {
              return current;
          }

          void stop() {
              current = lengthOfTask;
          }

          /**
           * Called from ProgressBarDemo to find out if the task has completed.
           */
          boolean done() {
              if (current >= lengthOfTask)
                  return true;
              else
                  return false;
          }

          String getMessage() {
              return statMessage;
          }

          /**
           * The actual long running task. This runs in a SwingWorker thread.
           */
          class ActualTask {
              ActualTask () {
                  //Fake a long task,
                  //making a random amount of progress every second.
                  while (current < lengthOfTask) {
                      try {
                          Thread.sleep(1000); //sleep for a second
                          current += Math.random() * 100 - Math.random() * 100; //make
      some progress
                          if (current > lengthOfTask) {
                              current = lengthOfTask;
                          }
                          statMessage = "Completed " + current +
                                        " out of " + lengthOfTask + ".";
                      } catch (InterruptedException e) {}
                  }
              }
          }
      }
      (Review ID: 128800)
      ======================================================================

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              Assignee:
              alexp Alexander Potochkin (Inactive)
              Reporter:
              bstrathesunw Bill Strathearn (Inactive)
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