cake.java

Java程序设计(美) David D. Riley著 机械工业出版社 书籍配套 代码

// Figure 9.18

import javax.swing.JComponent;
import java.awt.Graphics;
public abstract class Cake extends JComponent  {
	/**	post:	getX() == x   and   getY() == y
	 *			and  getWidth() == w   and   getHeight() == h 
	 */
	public Cake( int x, int y, int w, int h)  {
    	super();
		setBounds(x, y, w, h);
   }

	/**	post:	a cake is drawn with lines for cutting into eighths  */
	public void paint( Graphics g )   {
		paintCake(g);
		paintEighthCuts(g);
		paintChildren(g);
	}

	/**	post:	the cake is drawn  */
	protected abstract void paintCake( Graphics g );

	/**	post:	the lines are drawn for cutting the cake into eighths */
	protected abstract void paintEighthCuts( Graphics g );
}