Class SwingWorker

This class was adapted from the SwingWorker written by Hans Muller and presented in "Using a Swing Worker Thread" in the Swing Connection - http://java.sun.com/products/jfc/tsc/articles/threads/threads2.html

A closely related version of this class is described in "The Last Word in Swing Threads" in the Swing Connection - http://java.sun.com/products/jfc/tsc/articles/threads/threads3.html

This SwingWorker is a ThreadFactoryUser and implements Runnable. The default thread factory creates low-priority worker threads. A special constructor is provided for enabling a timeout. When the timeout expires, the worker thread is interrupted.

Note: Using a timeout of Long.MAX_VALUE will not impose a timeout but will create an additional thread of control that will respond to an interrupt even if the construct implementation ignores them.

Sample Usage

 import EDU.oswego.cs.dl.util.concurrent.TimeoutException;
 import EDU.oswego.cs.dl.util.concurrent.misc.SwingWorker;

 public class SwingWorkerDemo extends javax.swing.JApplet {

   private static final int TIMEOUT = 5000; // 5 seconds
   private javax.swing.JLabel status;
   private javax.swing.JButton start;
   private SwingWorker worker;

   public SwingWorkerDemo() {
     status = new javax.swing.JLabel("Ready");
     status.setHorizontalAlignment(javax.swing.SwingConstants.CENTER);
     getContentPane().add(status, java.awt.BorderLayout.CENTER);
     start = new javax.swing.JButton("Start");
     getContentPane().add(start, java.awt.BorderLayout.SOUTH);

     start.addActionListener(new java.awt.event.ActionListener() {
       public void actionPerformed(java.awt.event.ActionEvent evt) {
         if (start.getText().equals("Start")) {
           start.setText("Stop");
           status.setText("Working...");
           worker = new DemoSwingWorker(TIMEOUT);
           worker.start();
         } else {
           worker.interrupt();
         }
       }
     });
   }

   private class DemoSwingWorker extends SwingWorker {
     private static final java.util.Random RAND = new java.util.Random();
     public DemoSwingWorker(long msecs) {
       super(msecs);
     }
     protected Object construct() throws InterruptedException {
       // Take a random nap. If we oversleep, the worker times out.
       Thread.sleep(RAND.nextInt(2*TIMEOUT));
       return "Success";
     }
     protected void finished() {
       start.setText("Start");
       try {
         Object result = get();
         status.setText((String) result);
       }
       catch (java.lang.reflect.InvocationTargetException e) {
         Throwable ex = e.getTargetException();
         if (ex instanceof TimeoutException) {
           status.setText("Timed out.");
         } else if (ex instanceof InterruptedException) {
           status.setText("Interrupted.");
         } else {
           status.setText("Exception: " + ex);
         }
       }
       catch (InterruptedException ex) {
         // event-dispatch thread won't be interrupted 
         throw new IllegalStateException(ex+"");
       }
     }
   }
 }
 

Version: 3.0

[ Introduction to this package. ]

Author: Joseph Bowbeer Hans Muller