ATM Simulation Implementation - the Operator Panel

/*
 * Example ATM simulation - file OperatorPanel.java
 *
 * This file implements the class that manages the ATM's operator panel
 *
 * Copyright (c) 1997 - Russell C. Bjork
 *
 */

package atm.atmparts;
import java.awt.*;
import atm.util.Money;

//

Class OperatorPanel

public class OperatorPanel extends Panel
  { 

    //

    public OperatorPanel()
      { setLayout(new BorderLayout());
        setBackground(new Color(128,128,255));
        add("West", new Label("Operator Panel"));
        _message = new Label("Click ON button to turn ATM on");
        add("Center", _message);
        CheckboxGroup group = new CheckboxGroup();
        _offButton = new Checkbox("OFF", group, true);
        _onButton = new Checkbox("ON", group, false);
        Panel buttonPanel = new Panel();
        buttonPanel.add(_offButton);
        buttonPanel.add(_onButton);
        add("East", buttonPanel);
      }
    
    //

    public synchronized boolean switchOn()
      { // This will blink the "Click ON button ..." message when
        // the ATM is off
        boolean isOn = _onButton.getState();
        if (! isOn)
            if (_message.isShowing())
                _message.hide();
            else
                _message.show();
        else
            _message.hide();
        return isOn;
      }
    
    //

    public Money getInitialCash()
      { 
        int numberBills = -1;
        while (numberBills < 0)
          { QuestionDialog cashDialog = new 
              QuestionDialog("How many $20 bills are in the cash dispenser?", this);
            String answer = cashDialog.answer();
            if (answer != null)
                try
                  { numberBills = Integer.parseInt(answer); }
                catch (NumberFormatException e)
                  { }
           }
        return new Money(20 * numberBills);    
      }
      
    //

    // These fields are needed by the GUI
    
    private Label _message;
    private Checkbox _offButton;
    private Checkbox _onButton;
  }

//