heightfield.java

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

import javax.swing.JTextField;
import java.awt.event.*;
public class HeightField extends JTextField implements ActionListener {
	private Driver driver;

	/**	pre:	d != null  <br>
	 *	post:	driver == d
	 *			and  getX() == x   and   getY() == y
	 *			and   getWidth() == 60   and   getHeight() == 25 
	 */
    public HeightField( int x, int y, Driver d )  {
    	  	super();
			setBounds(x, y, 60, 25);
			addActionListener(this);
        	driver = d;
    }

	/**	pre:	driver != null  <br>
	 *	post:   the displayFall method from driver is performed
	 *			upon the integer value of this.
	 */
	public void actionPerformed( ActionEvent e )   {
        driver.displayFall( (new Integer(getText())).intValue() );
	}
}