import java.awt.*;

import java.applet.*;

import java.awt.event.*;

/*<applet code = TrafficSignal width = 500 height = 500></applet>*/

public class TrafficSignal extends Applet implements ItemListener

{

String msg = " ";

Checkbox red,green,yellow;

CheckboxGroup grp;

public void init()

{

grp = new CheckboxGroup();

red = new Checkbox("Red",grp,false);

green = new Checkbox("Green",grp,false);

yellow = new Checkbox("Yellow",grp,false);

add(red);

add(green);

add(yellow);

red.addItemListener(this);

green.addItemListener(this);

yellow.addItemListener(this);

}

public void itemStateChanged(ItemEvent e)

{

repaint();

}

public void paint(Graphics g)

{

msg = grp.getSelectedCheckbox().getLabel();

setBackground(Color.white);

g.drawOval(50, 50, 52, 52);

g.drawOval(50, 103, 52, 52);

g.drawOval(50, 156, 52, 52);

if(msg.equalsIgnoreCase("Green"))

{

g.setColor(Color.green);

g.fillOval(50, 156, 52, 52);

g.drawString("Go",110,190);

}

else if(msg.equalsIgnoreCase("yellow"))

{

g.setColor(Color.yellow);

g.fillOval(50, 103, 52, 52);

g.drawString("Ready",110,135);

}

else if(msg.equalsIgnoreCase("red"))

{

g.setColor(Color.red);

g.fillOval(50, 50, 52, 52);

g.drawString("Stop!",110,85);

}

}