/** Uses a SwingWorker to perform a time-consuming (and utterly fake) task. *//*  * LongTask.java is used by: *   ProgressBarDemo.java *   ProgressBarDemo2.java *   ProgressMonitorDemo */public class LongTask {    private int lengthOfTask;    private int current = 0;    private boolean done = false;    private boolean canceled = false;    private String statMessage;    public 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.     */    public void go() {        final SwingWorker worker = new SwingWorker() {            public Object construct() {                current = 0;                done = false;                canceled = false;                statMessage = null;                return new ActualTask();            }        };        worker.start();    }    /**     * Called from ProgressBarDemo to find out how much work needs     * to be done.     */    public int getLengthOfTask() {        return lengthOfTask;    }    /**     * Called from ProgressBarDemo to find out how much has been done.     */    public int getCurrent() {        return current;    }    public void stop() {        canceled = true;        statMessage = null;    }    /**     * Called from ProgressBarDemo to find out if the task has completed.     */    public boolean isDone() {        return done;    }    /**     * Returns the most recent status message, or null     * if there is no current status message.     */    public 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 (!canceled && !done) {                try {                    Thread.sleep(1000); //sleep for a second                    current += Math.random() * 100; //make some progress                    if (current >= lengthOfTask) {                        done = true;                        current = lengthOfTask;                    }                    statMessage = "Completed " + current +                                  " out of " + lengthOfTask + ".";                } catch (InterruptedException e) {                    System.out.println("ActualTask interrupted");                }            }        }    }}