
Composing an Applet of a Class Which Implements Runnable:

This example is a little complicated, so here's an overview. It has three
classes:

1. class click implements Runnable

2. class TOG implements ActionListener

3. class ccc extends Applet

The applet class is composed of five instances of the click class and
five instances of the TOG class. Inspect the click class. In particular,
pay close attention to its run() method and its think() method. Notice the
use of suspend(), resume(), and sleep().




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

class click implements Runnable {
  int count;
  ccc target;
  Thread t;
  boolean runflag=true;

  click(ccc x) {
    target = x;
    t = new Thread(this);
  }

  public void think() {
   if(runflag) t.suspend();
   else t.resume();

   runflag = ! runflag;
  }        

  public void run() {
     int inc = 10;
     while(true) {
      count+=inc;
      if(count>400 || count<5) inc*=-1;
      target.repaint();
      try{
        t.sleep(100);
      } catch(InterruptedException e) { }
    }

  }
}

class TOG implements ActionListener {
  click c;
  TOG(click x) {
    c=x;
  }
  public void actionPerformed(ActionEvent e) {
    if(!c.t.isAlive()) c.t.start();
    else  c.think();
  }
}
    

public class ccc2 extends Applet {
  click [] cl;
  Button [] b;
  
  public void init() {
    setBackground(Color.yellow);
    cl= new click[5];
    b=new Button[5];
    for(int i=0; i<cl.length; i++){
      cl[i]=new click(this);
      b[i]=new Button("TOGGLE "+(i+1));
    }
    for(int i=0; i<b.length; i++) {
      b[i].addActionListener(new TOG(cl[i]));
      add(b[i]);
    }
  }

  public void paint(Graphics g) {
    g.setColor(Color.red);
    g.fillRect(cl[0].count,50,10,10);
    g.setColor(Color.blue);
    g.fillRect(cl[1].count,70,10,10);
    g.setColor(Color.black);
    g.fillRect(cl[2].count,90,10,10);
    g.setColor(Color.magenta);
    g.fillRect(cl[3].count,110,10,10);
    g.setColor(Color.cyan);
    g.fillRect(cl[4].count,130,10,10);
  }
}