cardpanel.java

来自「含有uml的多个实例及实例的java源码。」· Java 代码 · 共 92 行

/*
 * ATM Example system - file BillsPanel.java    
 *
 * copyright (c) 2001 - Russell C. Bjork
 *
 */
 
package simulation;

import java.awt.*;
import java.awt.event.*;

/** The GUI panel that simulates the reading of the ATM card's magnetic stripe
 *  by asking the user to enter the number
 */
class CardPanel extends Panel
{
    /** Constructor
     */
    CardPanel()
    {
        setLayout(new GridLayout(0, 1, 0, 0));
        setFont(new Font("Monospaced", Font.PLAIN, 14));
        
        add(new Label("A real ATM would have a magnetic",
                      Label.CENTER));
        add(new Label("stripe reader to read the card",
                      Label.CENTER));
        add(new Label("For purposes of the simulation,",
                      Label.CENTER));
        add(new Label("please enter the card number manually.",
                      Label.CENTER));
        add(new Label("Then press RETURN",
                      Label.CENTER));
        add(new Label("(An invalid integer or an integer not",
                      Label.CENTER));
        add(new Label("greater than zero will be treated as",
                      Label.CENTER));
        add(new Label("an unreadable card)",
                      Label.CENTER));
        
        cardNumberField = new TextField(30);
        cardNumberField.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e)
            {
                synchronized(CardPanel.this)
                {
                    CardPanel.this.notify();
                }
            }
        });
        Panel cardNumberPanel = new Panel();
        cardNumberPanel.add(cardNumberField);
        add(cardNumberPanel);
    }
    
    /** Ask the customer to enter the number on the card
     *
     *  @return the number entered
     */
    synchronized int readCardNumber()
    {
        cardNumberField.setText("");
        
        cardNumberField.requestFocus();
        try
        {
            wait();
        }
        catch(InterruptedException e)
        { }
                
        int cardNumber;
        try
        {
            cardNumber = Integer.parseInt(cardNumberField.getText());
            if (cardNumber <= 0)
                cardNumber = -1;
        }
        catch(NumberFormatException e)
        {
            cardNumber = -1;
        }
        
        return cardNumber;
    }

    /** The field into which the card number is to be entered
     */
    private TextField cardNumberField;
}