/*
 * Gary Cornell and Cay S. Horstmann, Core Java (Book/CD-ROM)
 * Published By SunSoft Press/Prentice-Hall
 * Copyright (C) 1996 Sun Microsystems Inc.
 * All Rights Reserved. ISBN 0-13-565755-5
 *
 * Permission to use, copy, modify, and distribute this 
 * software and its documentation for NON-COMMERCIAL purposes
 * and without fee is hereby granted provided that this 
 * copyright notice appears in all copies. 
 * 
 * THE AUTHORS AND PUBLISHER MAKE NO REPRESENTATIONS OR 
 * WARRANTIES ABOUT THE SUITABILITY OF THE SOFTWARE, EITHER 
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE 
 * IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A 
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. THE AUTHORS
 * AND PUBLISHER SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED 
 * BY LICENSEE AS A RESULT OF USING, MODIFYING OR DISTRIBUTING 
 * THIS SOFTWARE OR ITS DERIVATIVES.
 */
 
/**
 * @version 1.00 07 Feb 1996 
 * @author Cay Horstmann
 */

import java.awt.*;

public class BounceThread extends Frame
{  public BounceThread()
   {  setTitle("BounceThread");
      canvas = new Canvas();
      add("Center", canvas);
      Panel p = new Panel();
      p.add(new Button("Start"));
      p.add(new Button("Close"));
      add("South", p);
   }
   
   public boolean handleEvent(Event evt)
   {  if (evt.id == Event.WINDOW_DESTROY) System.exit(0);
      return super.handleEvent(evt);
   }
   
   public boolean action(Event evt, Object arg)
   {  if (arg.equals("Start"))
      {  Ball b = new Ball(canvas);
         b.start();
      }
      else if (arg.equals("Close"))
         System.exit(0);
      else return super.action(evt, arg);
      return true;
   }
 
   public static void main(String[] args)
   {  Frame f = new BounceThread();
      f.resize(300, 200);
      f.show();  
   }
   
   private Canvas canvas;
}

class Ball extends Thread
{  public Ball(Canvas c) { box = c; }

   public void draw()
   {  Graphics g = box.getGraphics();
      g.fillOval(x, y, XSIZE, YSIZE);
      g.dispose();
   }
   
   public void move()
   {  Graphics g = box.getGraphics();
      g.setXORMode(box.getBackground());
      g.fillOval(x, y, XSIZE, YSIZE);
      x += dx;
      y += dy;
      Dimension d = box.size();
      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()
   {  draw();
      for (int i = 1; i <= 1000; i++)
      {  move();
         try { Thread.sleep(5); } catch(InterruptedException e) {}
      }
   }
   
   private Canvas 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;   
}