import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.beans.*;
import java.util.Random;

class JProgressBarSample extends JPanel
   implements ActionListener, PropertyChangeListener {

   private JProgressBar progressBar;
   private JButton startButton;
   private JTextArea taskOutput;
   private Task task;

   class Task extends SwingWorker<Void, Void> {
      public Void doInBackground() {
         Random random = new Random();
         int progress = 0;
         setProgress(0);
         while (progress < 100) {
            try {
               Thread.sleep(random.nextInt(1000));
            } catch (InterruptedException ignore) {}
            progress += random.nextInt(10);
            setProgress(Math.min(progress, 100));
         }
         return null;
      }
      public void done() {
         Toolkit.getDefaultToolkit().beep();
         startButton.setEnabled(true);
         taskOutput.append("処理終了\n");
      }
   }
   public JProgressBarSample() {
      super(new BorderLayout());

      startButton = new JButton("処理開始");
      startButton.setActionCommand("start");
      startButton.addActionListener(this);

      progressBar = new JProgressBar(0, 100);
      progressBar.setValue(0);
      progressBar.setStringPainted(true);
      progressBar.setPreferredSize(new Dimension(380,25));

      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);

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

   }
   public void actionPerformed(ActionEvent evt) {
      startButton.setEnabled(false);
      setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR));
      task = new Task();
      task.addPropertyChangeListener(this);
      task.execute();
   }
   public void propertyChange(PropertyChangeEvent evt) {
      if ("progress" == evt.getPropertyName()) {
         int progress = (Integer) evt.getNewValue();
         progressBar.setValue(progress);
         taskOutput.append(String.format(
            "Completed %d%% of task.\n", task.getProgress()));
      } 
   }
   private static void createAndShowGUI() {
      JFrame frame = new JFrame(
                   "JProgressBarを使ってプログレスバーを表示");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

      JComponent newContentPane = new JProgressBarSample();
      newContentPane.setOpaque(true);
      frame.setContentPane(newContentPane);

      frame.pack();
      frame.setVisible(true);
   }
   public static void main(String[] args) {
     SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            createAndShowGUI();
         }
      });
   }
}