import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.BorderFactory;
import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.JPanel;

class ArdoiseBoutons extends JPanel {
    static final long serialVersionUID = 1;
    private boolean possedeDisque = true;
    public ArdoiseBoutons() {
	setBackground(Color.YELLOW);
	setPreferredSize(new Dimension(200, 150));
    } 

    public void setPossedeDisque(boolean possedeDisque) {
	this.possedeDisque = possedeDisque;
    }
    
    public void dessiner(Graphics g) {
	g.setColor(Color.RED);	
	g.fillOval(60, 35, 80, 80);
   }
    
    public void paintComponent(Graphics g) {
	super.paintComponent(g);
	if (possedeDisque) dessiner(g);
    }
}

class MesBoutons extends JPanel implements  ActionListener {  
    private JButton trace = new JButton("trace");
    private JButton efface = new JButton("efface");
    private ArdoiseBoutons ardoise = new ArdoiseBoutons();
    
    MesBoutons() {
	setLayout(new BorderLayout(5, 5));
	JPanel lesBoutons = new JPanel();
	lesBoutons.add(trace);
	lesBoutons.add(efface);
	add(lesBoutons, BorderLayout.NORTH);
	add(ardoise, BorderLayout.CENTER);
	trace.addActionListener(this);
	efface.addActionListener(this);
	setBorder(BorderFactory.createLineBorder(Color.BLACK));
    }    
    
    public void actionPerformed(ActionEvent e) {
	if (e.getSource() == trace)  ardoise.setPossedeDisque(true);
	else if (e.getSource() == efface) ardoise.setPossedeDisque(false);
	ardoise.repaint();
    }
}

public class BoutonsA extends JApplet {
    public void init() {
	setLayout(new FlowLayout(FlowLayout.CENTER));
	add(new MesBoutons());
    }
}