billspanel.java

含有uml的多个实例及实例的java源码。

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

import banking.Money;

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

/** The GUI panel that allows the operator to enter the number of bills in the
 *  ATM at startup
 */
class BillsPanel extends Panel
{
    /** Constructor
     */
    BillsPanel()
    {
        setLayout(new GridLayout(0, 1, 0, 0));
        setFont(new Font("Monospaced", Font.PLAIN, 14));
        
        add(new Label("A real ATM would have a mechanism to sense",
                      Label.CENTER));
        add(new Label("or allow the operator to enter the number",
                      Label.CENTER));
        add(new Label("of $20 bills in the cash dispenser.",
                      Label.CENTER));
        add(new Label("For purposes of the simulation,",
                      Label.CENTER));
        add(new Label("please enter the number of $20 bills manually.",
                      Label.CENTER));
        add(new Label("Then press RETURN",
                      Label.CENTER));
        
        billsNumberField = new TextField(30);
        billsNumberField.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e)
            {
                synchronized(BillsPanel.this)
                {
                    BillsPanel.this.notify();
                }
            }
        });
        Panel billsNumberPanel = new Panel();
        billsNumberPanel.add(billsNumberField);
        add(billsNumberPanel);  
    }

    /** Ask the operator to enter the number of bills in the cash dispenser
     *
     *  @return the number entered
     */
    synchronized int readBills()
    {
        boolean validNumberRead = false;
        int billsNumber = 0;
        
        billsNumberField.setText("");
        
        while(! validNumberRead)
        {
            billsNumberField.requestFocus();
            try
            {
                wait();
            }
            catch(InterruptedException e)
            { }
                    
            try
            {
                billsNumber = Integer.parseInt(billsNumberField.getText());
                if (billsNumber >= 0)
                    validNumberRead = true;
                else
                    getToolkit().beep();
            }
            catch(NumberFormatException e)
            {
                getToolkit().beep();
            }
            if (! validNumberRead)
            {
                billsNumberField.setText("Must be a valid integer >= 0");
                billsNumberField.selectAll();
            }
        }
        return billsNumber;
    }
    
    /** The field into which the number of bills is to be entered
     */
    private TextField billsNumberField;
}