Progress Monitor and Swingworker : SwingWorker « Swing « Java Tutorial

1. Java Tutorial
2. Swing
3. SwingWorker

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 *
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 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
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 *   - Redistributions in binary form must reproduce the above copyright
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 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * 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,
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import java.awt.BorderLayout;
import java.awt.Insets;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.Random;

import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.ProgressMonitor;
import javax.swing.SwingWorker;

public class ProgressMonitorDemo extends JPanel implements ActionListener,
    PropertyChangeListener {

  private ProgressMonitor progressMonitor;
  private JButton startButton;
  private JTextArea taskOutput;
  private Task task;

  class Task extends SwingWorker<Void, Void> {
    @Override
    public Void doInBackground() {
      Random random = new Random();
      int progress = 0;
      setProgress(0);
      try {
        Thread.sleep(1000);
        while (progress < 100 && !isCancelled()) {
          // Sleep for up to one second.
          Thread.sleep(random.nextInt(1000));
          // Make random progress.
          progress += random.nextInt(10);
          setProgress(Math.min(progress, 100));
        }
      } catch (InterruptedException ignore) {
      }
      return null;
    }

    @Override
    public void done() {
      Toolkit.getDefaultToolkit().beep();
      startButton.setEnabled(true);
      progressMonitor.setProgress(0);
    }
  }

  public ProgressMonitorDemo() {
    super(new BorderLayout());

    // Create the demo's UI.
    startButton = new JButton("Start");
    startButton.setActionCommand("start");
    startButton.addActionListener(this);

    taskOutput = new JTextArea(5, 20);
    taskOutput.setMargin(new Insets(5, 5, 5, 5));
    taskOutput.setEditable(false);

    add(startButton, BorderLayout.PAGE_START);
    add(new JScrollPane(taskOutput), BorderLayout.CENTER);
    setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20));

  }

  /**
   * Invoked when the user presses the start button.
   */
  public void actionPerformed(ActionEvent evt) {
    progressMonitor = new ProgressMonitor(ProgressMonitorDemo.this,
        "Running a Long Task", "", 0, 100);
    progressMonitor.setProgress(0);
    task = new Task();
    task.addPropertyChangeListener(this);
    task.execute();
    startButton.setEnabled(false);
  }

  /**
   * Invoked when task's progress property changes.
   */
  public void propertyChange(PropertyChangeEvent evt) {
    if ("progress" == evt.getPropertyName()) {
      int progress = (Integer) evt.getNewValue();
      progressMonitor.setProgress(progress);
      String message = String.format("Completed %d%%.\n", progress);
      progressMonitor.setNote(message);
      taskOutput.append(message);
      if (progressMonitor.isCanceled() || task.isDone()) {
        Toolkit.getDefaultToolkit().beep();
        if (progressMonitor.isCanceled()) {
          task.cancel(true);
          taskOutput.append("Task canceled.\n");
        } else {
          taskOutput.append("Task completed.\n");
        }
        startButton.setEnabled(true);
      }
    }

  }

  /**
   * Create the GUI and show it. For thread safety, this method should be
   * invoked from the event-dispatching thread.
   */
  private static void createAndShowGUI() {
    // Create and set up the window.
    JFrame frame = new JFrame("ProgressMonitorDemo");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    // Create and set up the content pane.
    JComponent newContentPane = new ProgressMonitorDemo();
    newContentPane.setOpaque(true); // content panes must be opaque
    frame.setContentPane(newContentPane);

    // Display the window.
    frame.pack();
    frame.setVisible(true);
  }

  public static void main(String[] args) {
    // Schedule a job for the event-dispatching thread:
    // creating and showing this application's GUI.
    javax.swing.SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        createAndShowGUI();
      }
    });
  }
}