import java.awt.*;import java.awt.event.*;import javax.swing.*;/* * ProgressBarDemo.java is a 1.4 application that requires these files: *   LongTask.java *   SwingWorker.java */public class ProgressBarDemo extends JPanel                             implements ActionListener {    public final static int ONE_SECOND = 1000;    private JProgressBar progressBar;    private Timer timer;    private JButton startButton;    private LongTask task;    private JTextArea taskOutput;    private String newline = "\n";    public ProgressBarDemo() {        super(new BorderLayout());        task = new LongTask();        //Create the demo's UI.        startButton = new JButton("Start");        startButton.setActionCommand("start");        startButton.addActionListener(this);        progressBar = new JProgressBar(0, task.getLengthOfTask());        progressBar.setValue(0);        progressBar.setStringPainted(true);        taskOutput = new JTextArea(5, 20);        taskOutput.setMargin(new Insets(5,5,5,5));        taskOutput.setEditable(false);        taskOutput.setCursor(null); //inherit the panel's cursor                                    //see bug 4851758        JPanel panel = new JPanel();        panel.add(startButton);        panel.add(progressBar);        add(panel, BorderLayout.PAGE_START);        add(new JScrollPane(taskOutput), BorderLayout.CENTER);        setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20));        //Create a timer.        timer = new Timer(ONE_SECOND, new ActionListener() {            public void actionPerformed(ActionEvent evt) {                progressBar.setValue(task.getCurrent());                String s = task.getMessage();                if (s != null) {                    taskOutput.append(s + newline);                    taskOutput.setCaretPosition(                            taskOutput.getDocument().getLength());                }                if (task.isDone()) {                    Toolkit.getDefaultToolkit().beep();                    timer.stop();                    startButton.setEnabled(true);                    setCursor(null); //turn off the wait cursor                    progressBar.setValue(progressBar.getMinimum());                }            }        });    }    /**     * Called when the user presses the start button.     */    public void actionPerformed(ActionEvent evt) {        startButton.setEnabled(false);        setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR));        task.go();        timer.start();    }    /**     * Create the GUI and show it.  For thread safety,     * this method should be invoked from the     * event-dispatching thread.     */    private static void createAndShowGUI() {        //Make sure we have nice window decorations.        JFrame.setDefaultLookAndFeelDecorated(true);        //Create and set up the window.        JFrame frame = new JFrame("ProgressBarDemo");        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        //Create and set up the content pane.        JComponent newContentPane = new ProgressBarDemo();        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();            }        });    }}