Java Applet: CounterApplet.html

Invoke this with appletviewer CounterApplet.html

<APPLET CODE=CounterApplet.class 
        CODEBASE=./ 
        WIDTH=500 HEIGHT=20>
</APPLET>

Java Applet Skeleton: CounterApplet.java

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

public class CounterApplet extends Applet implements Runnable
{
   int count = 0;
   Thread myThread;
   
   public void init() {...}
   public void start() {...}
   public void stop() {...}
   public void run() {...}
   public void paint(Graphics g) {...}

   private class ClickListener extends MouseAdapter {...}   
}

CounterApplet: overriding init(), start(), ...

   public void init()
   {
      addMouseListener(new ClickListener());
      myThread = null;
      count = 0;
   }
   
   public void start()
   {
      myThread = new Thread(this,"CounterApplet");
      myThread.start();
   }
   
   public void stop()
   {
      myThread.stop();
      myThread = null;
   }

CounterApplet: threading with run()

   public void run()
   {
      while (Thread.currentThread() == myThread)
      {
         count ++;
         repaint();
         try
         {
            myThread.sleep(100);
         }
         catch (InterruptedException e)
         {
            System.err.println("Caught Interrupt.");
            System.exit(-1);
         }
      }
   }

CounterApplet: overriding paint()

   public void paint(Graphics g)
   {
      g.setColor(new Color((count * 10) % 256, 128, 0));
    
      // display counter.
      g.drawString(Integer.toString(count),5,15);
   }

CounterApplet: ClickListener inner class

   // we will toggle start/stop.
   private class ClickListener extends MouseAdapter
   {
      public void mouseClicked(MouseEvent e)
      {
         if (myThread==null)
            start();
         else
            stop();
      }
   }

Java Application Skeleton: CounterFrame.java

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

public class CounterFrame extends Frame implements Runnable
{
   int count = 0;   Thread myThread;
   
   public CounterFrame() {...}
   public void start() {...}
   public void stop() {...}
   public void run() {...}
   public void paint(Graphics g) {...}
   public static void main(String [] args) {...}
   
   private class ClickListener extends MouseAdapter {...}
}

CounterFrame: providing CounterFrame() and main()

   public CounterFrame()
   {
      addMouseListener(new ClickListener());
      myThread = null;
      count = 0;
   }
   
   public static void main(String [] args)
   {
      CounterFrame cf = new CounterFrame();
      
      cf.setSize(400,50);
      
      cf.show();
   }

CounterFrame: threading with start() and stop()

   public void start()
   {
      myThread = new Thread(this,"CounterFrame");
      myThread.start();
   }
   
   public void stop()
   {
      myThread.stop();
      myThread = null;
   }

CounterFrame: threading with run()

   public void run()
   {
      while (Thread.currentThread() == myThread)
      {
         count ++;
         repaint();
         try
         {
            myThread.sleep(100);
         }
         catch (InterruptedException e)
         {
            System.err.println("Caught Interrupt.");
            System.exit(-1);
         }
      }
   }

CounterFrame: overriding paint()

   public void paint(Graphics g)
   {
      g.setColor(new Color((count * 10) % 256, 128, 0));
    
      // display counter.
      g.drawString(Integer.toString(count),10,40);
   }

CounterFrame: ClickListener inner class

   private class ClickListener extends MouseAdapter
   {
      public void mouseClicked(MouseEvent e)
      {
         if (myThread==null)
            start();
         else
            stop();
      }
   }