14

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
class J {
	public static void main(String[] arg) {
		JFrame frame = new JFrame();
		J14 component = new J14();
		frame.setBounds(0,0,400,300);
		frame.add(component);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setVisible(true);
	}
}

class J14light extends JComponent {
	boolean flg;
	Color color;
	J14light(Color color) {
		flg = false;
		this.color = color;
	}
	public void setFlg(boolean flg) {
		this.flg = flg;
	}
	public void paintComponent(Graphics g) {
		if(flg)
			g.setColor(color);
		else
			g.setColor(Color.GRAY);
		g.fillOval(0,0,getWidth(), getHeight());
	}
}

class J14 extends JComponent {
	J14light light;
	J14() {
		light = new J14light(Color.RED);
		light.setBounds(150,70,60,60);
		light.setFlg(true);
		add(light);
	}
	public void paintComponent(Graphics g) {
		g.setColor(Color.BLUE);
		g.fillRect(0,0,getWidth(),getHeight());
		g.setColor(Color.WHITE);
		g.fillRect(50,50,260,100);
	}
}
/*

演習問題

赤色の●を、黄色に変更してください。

*/