// Program to desmonstrate action triggered by pushing a button

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

public class TrafficLight extends java.applet.Applet implements ActionListener
{
    TextField m1, m2;
    Button b1, b2, b3;

    public void init ()
    {    
        m1 = new TextField(80);
        m1.setText("What are you going to do when the light is:");
        b1 = new Button("GREEN");
        b2 = new Button("YELLOW");
        b3 = new Button("RED");
        m2 = new TextField(80);
        add(m1) ;
        add(b1) ;
        add(b2) ;
        add(b3) ;
        add(m2) ;
        b1.addActionListener(this);
        b2.addActionListener(this);
        b3.addActionListener(this);
    }
    
    public void actionPerformed(ActionEvent event)
    {
        Object cause = event.getSource();

        if (cause == b1)
        {
            m2.setText("Keep on rolling.");
        }
        if (cause == b2)
        {
            m2.setText("Stop if you can!");
        }
        if (cause == b3)
        {
            m2.setText("You must stop.");
        }
    }
}