ATM Simulation Implementation - the Display

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

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

//

Class Display

public class Display extends Panel
  {

    //

    public Display()
      { setLayout(new GridLayout(GUILayout.DISPLAYABLE_LINES, 1));
        setBackground(new Color(0, 96, 0));  // Dark green
        setForeground(Color.white);
        _line = new Label[GUILayout.DISPLAYABLE_LINES];
        for (int i = 0; i < GUILayout.DISPLAYABLE_LINES; i ++)
          { _line[i] = new Label("");
            add(_line[i]);
          }
        _currentLine = 0;
      }
            
    //

    public void requestCard()
      { write("Please insert your card to begin");
      }
    
    //

    public void requestPIN()
      { write(
        "Please enter your Personal Identification Number (PIN)\n" +
        "Press ENTER when finished or CLEAR to start over");
      }
         
    //

    public void displayMenu(String whatToChoose,
                int numItems,
                String items[])
      { write(whatToChoose);
        for (int i = 0; i < numItems; i ++)
            write((i + 1) + ") " + items[i]); 
      }
    
    
    //

    public void requestAmountEntry()
      { write( 
        "Please enter amount.\n" +
        "Press ENTER when finished or CLEAR to start over");
      }
    
    //

    public void requestDepositEnvelope()
      { write(
        "Please deposit an envelope in the slot");
      }
    
    //

    public void reportCardUnreadable()
      { write(
        "Sorry, your card was inserted incorrectly or\n" + 
        "is unreadable.\n" +
        "Please try inserting your card again");
      }
    
    //

    public void reportTransactionFailure(String explanation)
      { write(explanation);
        write("\n" +
             "Do you want to perform another transaction\n" +
             "(1 = Yes, 2 = No)?");
      }
    
    //

    public void requestReEnterPIN()
      { write(
        "Your PIN was entered incorrectly.\n" +
        "Please re-enter it");
      }
    
    //

    public void reportCardRetained()
      { write( 
        "Your PIN was entered incorrectly.\n" +
        "Your card has been retained - please contact the bank");
        try
          { Thread.sleep(10 * 1000); }
        catch (InterruptedException e)
          { }
      }
    
    //

    public void echoInput(String echo)
      { _line[GUILayout.DISPLAYABLE_LINES - 1].setText("          " + echo);
      }
     
    //

    public void clearDisplay()
      { for (int i = 0; i < GUILayout.DISPLAYABLE_LINES; i ++)
            _line[i].setText("");
        _currentLine = 0;
      }
      
    //

    // Private method and instance variables needed for GUI
    
    private void write(String s)
      // Write one or more lines; may contain multiple lines delimited by \n 
      { StringTokenizer t = new StringTokenizer(s, "\n", false);
        while (t.hasMoreTokens())
          { try
              { _line[_currentLine ++].setText(t.nextToken()); }
            catch (Exception e)
              { }
           }
      }
      
    private Label          _line[];
    private int            _currentLine;
 
  }     

//