//------------
// Introduction to Programming Using Java: An Object-Oriented Approach
//	Arnow/Weiss
//------------
import java.awt.*;
import java.awt.event.*;
import java.applet.*;

public class RedGreen2 extends Applet implements ActionListener{
	public void init() {
		setLayout(new BorderLayout(2,2));
		b = new Button("start");
		b.addActionListener(this);
		c = new Canvas();
		add("West",b);
		add("East",c);
		c.setSize(100,50);
	}

	public void actionPerformed(ActionEvent ae) {
		String s = ae.getActionCommand();
		if (s.equals("start"))
			handleStart();
		else if (s.equals("resume"))
			handleResume();
		else if (s.equals("stop"))
			handleStop();
	}

	private void handleStart() {
		b.setLabel("stop");
		rgt = new RedGreenThread(c);
		rgt.start();
	}

	private void handleResume() {
		b.setLabel("stop");
		rgt.myResume();
	}

	private void handleStop() {
		b.setLabel("resume");
		rgt.mySuspend();
	}

	Button          b;
	Canvas          c;
	RedGreenThread  rgt=null;
}

class RedGreenThread extends Thread {
	RedGreenThread(Canvas c) {
		this.c = c;
	}

	public void run() {
		Graphics gc = c.getGraphics();
		amRunning = true;
		while (true)
			if (amRunning) {
				gc.setColor(new Color(200,50,50));
				gc.fillRect(5,5,90,40);
				try {
					sleep(50);
				} catch(Exception e) {}
				gc.setColor(new Color(50,200,50));
				gc.fillRect(5,5,90,40);
				try {
					sleep(50);
				} catch(Exception e) {}
			}
	}

	public void mySuspend() {
		amRunning=false;
	}

	public void myResume() {
		amRunning=true;
	}

	Canvas c;
	boolean amRunning=false;
}