driver.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 java.awt.Label;
import java.awt.event.*;
import javax.swing.*;

/** Text Message Permutation (Figure 12.6)
 *  Author: David Riley
 *  Date: January, 2005
 */
public class Driver implements ActionListener  {
	JFrame window;
	JTextField inField;
	Label inLabel, outLabel;
	JButton button;

	/** post:	window is instantiated to contain inField, inLabel
	 *					outLabel and button
	 *			and outLabel.getText() == 矣
	 *			and button誷 events are delagated to this
	 */
	public Driver()  {
		window = new JFrame("Word Scramble");
		window.setBounds(20, 20, 300, 200);
		window.setLayout(null);
		window.setVisible(true);

		inLabel = new Label("Type your message below.");
		inLabel.setBounds(10, 10, 200, 20);
		window.add(inLabel, 0);
		inField = new JTextField();
		inField.setBounds(30, 40, 250, 25);
		window.add(inField, 0);

		button = new JButton("Click here to scramble");
		button.setBounds(20, 90, 260, 25);
		button.addActionListener(this);
		window.add(button, 0);
		outLabel = new Label("");
		outLabel.setBounds(30, 130, 200, 20);
		window.add(outLabel, 0);
		window.repaint();
	}

	/**	post:	outLabel is updated to be a randomly chosen
	 *			permutation of inField.getText()
	 */
	public void actionPerformed(ActionEvent e)   {
		String inStr = inField.getText();
		String outStr;
		char[] message = new char[ inStr.length() ];
		int rnd1, rnd2;
		char temp;
		for  (int j=0; j!=message.length; j++ )   {
			message[j] = inStr.charAt(j);
		}
        
		for (int r=1; r != inStr.length()*2+1; r++) {
			rnd1 = (int)( Math.random()*message.length );
			rnd2 = (int)( Math.random()*message.length );
			temp = message[rnd1];
			message[rnd1] = message[rnd2];
			message[rnd2] = temp;
		}
        
		outStr = "";
		for (char c : message)  {
			outStr = outStr + c;
		}
		outLabel.setText(outStr);
		window.repaint();
	}
}