import java.awt.*;
import java.awt.event.*;

import javax.swing.*; 

public class ProgressBarDemo extends JFrame {

    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;

    public ProgressBarDemo() {
        super("ProgressBarDemo");
        newline = System.getProperty("line.separator");

	task = new LongTask();

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

	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);

	JPanel panel = new JPanel();
	panel.add(startButton);
	panel.add(progressBar);

	JPanel contentPane = new JPanel();
	contentPane.setLayout(new BorderLayout());
	contentPane.add(panel, BorderLayout.NORTH);
	contentPane.add(new JScrollPane(taskOutput), BorderLayout.CENTER);
	contentPane.setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20));
	setContentPane(contentPane);

	//create a timer and a task
	timer = new Timer(ONE_SECOND, new TimerListener());
    }

    //the actionPerformed method in this class
    //is called each time the Timer "goes off"
    class TimerListener implements ActionListener {
        public void actionPerformed(ActionEvent evt) {
	    progressBar.setValue(task.getCurrent());
            taskOutput.append(task.getMessage() + newline);
            taskOutput.setCaretPosition(taskOutput.getDocument().getLength());
	    if (task.done()) {
		Toolkit.getDefaultToolkit().beep();
		timer.stop();
		startButton.setEnabled(true);
	        progressBar.setValue(progressBar.getMinimum());
	    }
        }
    }

    //the actionPerformed method in this class
    //when the user presses the start button
    class ButtonListener implements ActionListener {
        public void actionPerformed(ActionEvent evt) {
	    startButton.setEnabled(false);
	    task.go();
	    timer.start();
	}
    }
    
    public static void main(String[] args) {

        JFrame frame = new ProgressBarDemo();

        WindowListener l = new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        };
        frame.addWindowListener(l);

        frame.pack();
        frame.setVisible(true);
    }
}