/**
 * @version 1.20 1999-04-25
 * @author Cay Horstmann
 */

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class BounceExpress
{  public static void main(String[] args)
   {  JFrame frame = new BounceExpressFrame();
      frame.show();
   }
}

class BounceExpressFrame extends JFrame
{  public BounceExpressFrame()
   {  setSize(300, 200);
      setTitle("Bounce");

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

      Container	contentPane = getContentPane();
      canvas = new JPanel();
      contentPane.add(canvas, "Center");
      JPanel p = new JPanel();
      addButton(p, "Start",
	 new ActionListener()
	 {  public void	actionPerformed(ActionEvent evt)
	    {  for (int	i = 0; i < 5; i++)
	       {  Ball b = new Ball(canvas, Color.black);
		  b.setPriority(Thread.NORM_PRIORITY);
		  b.start();
	       }
	    }
	 });

      addButton(p, "Express",
	 new ActionListener()
	 {  public void	actionPerformed(ActionEvent evt)
	    {  for (int	i = 0; i < 5; i++)
	       {  Ball b = new Ball(canvas, Color.red);
		  b.setPriority(Thread.NORM_PRIORITY + 2);
		  b.start();
	       }
	    }
	 });

      addButton(p, "Close",
	 new ActionListener()
	 {  public void	actionPerformed(ActionEvent evt)
	    {  canvas.setVisible(false);
	       System.exit(0);
	    }
	 });
      contentPane.add(p, "South");
   }

   public void addButton(Container c, String title,
      ActionListener a)
   {  JButton b	= new JButton(title);
      c.add(b);
      b.addActionListener(a);
   }

   private JPanel canvas;
}

class Ball extends Thread
{  public Ball(JPanel b, Color c) { box	= b; color = c;	}

   public void draw()
   {  Graphics g = box.getGraphics();
      g.setColor(color);
      g.fillOval(x, y, XSIZE, YSIZE);
      g.dispose();
   }

   public void move()
   {  if (!box.isVisible()) return;
      Graphics g = box.getGraphics();
      g.setXORMode(box.getBackground());
      g.setColor(color);
      g.fillOval(x, y, XSIZE, YSIZE);
      x	+= dx;
      y	+= dy;
      Dimension	d = box.getSize();
      if (x < 0)
      {	x = 0; dx = -dx; }
      if (x + XSIZE >= d.width)
      {	x = d.width - XSIZE; dx	= -dx; }
      if (y < 0)
      {	y = 0; dy = -dy; }
      if (y + YSIZE >= d.height)
      {	y = d.height - YSIZE; dy = -dy;	}
      g.fillOval(x, y, XSIZE, YSIZE);
      g.dispose();
   }

   public void run()
   {  try
      {	 draw();
	 for (int i = 1; i <= 1000; i++)
	 {  move();
	    sleep(5);
	 }
      }
      catch(InterruptedException e) {}
   }

   private JPanel box;
   private static final	int XSIZE = 10;
   private static final	int YSIZE = 10;
   private int x = 0;
   private int y = 0;
   private int dx = 2;
   private int dy = 2;
   private Color color;
}