package com;

import java.awt.*;

import java.awt.event.*;

public class DemoThreadGroup extends Frame implements Runnable,ActionListener {

int x1,x2,x3;

Button b1,b2;

Thread t1,t2,t3;

ThreadGroup tg;

public DemoThreadGroup() {

setLayout(new FlowLayout());

x1=50;

x2=50;

x3=50;

tg=new ThreadGroup("tg");

t1=new Thread(tg,this);

t2=new Thread(tg,this);

t3=new Thread(tg,this);

b1=new Button("Start");

b2=new Button("Stop");

add(b1);

add(b2);

t1.start();

t2.start();

t3.start();

b1.addActionListener(this);

b2.addActionListener(this);

setSize(500,500);

setVisible(true);

addWindowListener(new WindowAdapter() {

public void windowClosing(WindowEvent we)

{

dispose();

}

});

}

public static void main(String[] args) {

new DemoThreadGroup();

}

public void run() {

while(true)

{

if(Thread.currentThread().equals(t1))

{

x1=x1+2;

try {

Thread.sleep(500);

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

if(Thread.currentThread().equals(t2))

{

x2=x2+10;

try {

Thread.sleep(500);

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

if(Thread.currentThread().equals(t3))

{

x3=x3+5;

try {

Thread.sleep(500);

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

repaint();

}

}

public void paint(Graphics g)

{

g.setColor(Color.red);

g.fillOval(x1, 150, 50, 50);

g.setColor(Color.green);

g.fillOval(x2, 350, 50, 50);

g.setColor(Color.blue);

g.fillOval(x3, 250 , 50, 50);

}

public void actionPerformed(ActionEvent e) {

if(e.getSource().equals(b1))

{

tg.resume();

}

if(e.getSource().equals(b2))

{

tg.suspend();

}

}

}