ATM Simulation Implementation

// ATM Simulation Implementation - the Keyboard

ATM Simulation Implementation - the Keyboard


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

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

//

Class Keyboard


public class Keyboard extends Panel
  {

    //


    public Keyboard()
      { super();
        setLayout(new GridLayout(4,3));
        _numberKey = new Button[10];
        for (int i = 1; i < 10; i ++)
          { _numberKey[i] = new Button("" + i);
            add(_numberKey[i]);
          }
        _enterKey = new Button("Enter");
        _enterKey.setForeground(Color.black);
        _enterKey.setBackground(new Color(128, 128, 255));
        add(_enterKey);
        _numberKey[0] = new Button("0");
        add(_numberKey[0]);
        _clearKey = new Button("Clear");
        _clearKey.setForeground(Color.black);
        _clearKey.setBackground(new Color(255, 128, 128));
        add(_clearKey);
      }
               
    //


    public int readPIN(Display echoOn)
      { StringBuffer result = new StringBuffer("");
        StringBuffer echo = new StringBuffer("");
        int keyClicked;
        do
          { keyClicked = inKey();
            switch (keyClicked)
              { case ENTER:
                    // If a legitimate integer has been entered, return it;
                    // otherwise fall through to clear case and make user
                    // start over
                    try
                      { return Integer.parseInt(result.toString()); }
                    catch (NumberFormatException e)
                      { }
                case CLEAR:
                    result.setLength(0);
                    echo.setLength(0);
                    break;
                default:
                    result.append(keyClicked);
                    echo.append('*');
              }
            echoOn.echoInput(echo.toString());
          }
        while (true);
      }
   
    //


    public int readMenuChoice(int numItems)
      {
        int key;
        do
          { key = inKey();
          }
        while (key < 1 || key > numItems);
        return key;
      }
    
    //


    public Money readAmountEntry(Display echoOn)
      { StringBuffer cents = new StringBuffer("  "),
                     dollars = new StringBuffer("");
        echoOn.echoInput(".  ");
        int keyClicked;
        do
          { keyClicked = inKey();
            switch (keyClicked)
              { case ENTER:
                    // If a legitimate amout has been entered, return it;
                    // otherwise fall through to clear case and make user
                    // start over
                    try
                      { if (dollars.length() == 0) dollars.append('0');
                        if (cents.charAt(0) == ' ') cents.setCharAt(0, '0');
                        return new Money(Integer.parseInt(dollars.toString()),
                                         Integer.parseInt(cents.toString()));
                      }
                    catch (NumberFormatException e)
                      { }
                case CLEAR:
                    cents.setLength(0);
                    cents.append("  ");
                    dollars.setLength(0);
                    break;
                default:
                    if (cents.charAt(0) != ' ')
                        dollars.append(cents.charAt(0));
                    cents.setCharAt(0, cents.charAt(1));
                    cents.setCharAt(1, Character.forDigit(keyClicked, 10));
              }
            echoOn.echoInput(dollars.toString() + "." + cents.toString());
          }
        while (true);
      }

    //


    // Methods and private data needed for GUI
    
    private synchronized int inKey()
      { _buttonClicked = NONE;
        requestFocus();
        do
          { try
              { wait(); }
            catch (InterruptedException e)
              { }
          }
        while (_buttonClicked == NONE);
        return _buttonClicked;
      }
              
    public synchronized boolean action(Event e, Object arg)
      { for (int i = 0; i < 10; i ++)
            if (e.target == _numberKey[i])
                _buttonClicked = i;
        if (e.target == _enterKey)
            _buttonClicked = ENTER;
        if (e.target == _clearKey)
            _buttonClicked = CLEAR;
        if (_buttonClicked != NONE)
          { notify();
            return true;
          }
        else
            return false;
      }
                  
    // Each individual key is represented by a button
    
    private Button _numberKey[];  // _numberKey[i] represents digit i
    private Button _enterKey;
    private Button _clearKey;
    
    // Record the button clicked
    
    private int _buttonClicked;
    private static final int NONE = -1;
    private static final int ENTER = 10;
    private static final int CLEAR = 11; 
  }
  
//