SL Mastery Aspects : records, objects, arrays, simple selection, repetition, complex selection.

source code

Revised source code for Biscuit2.java

import java.awt.*;
import java.awt.event.*;
/**
* Example application that stores Biscuit's in an array
*
* @author Mr J
* @version 1.0
*/
public class BiscuitWindow extends Frame implements ActionListener
{
   // GUI objects
   private BiscuitDisplay display = new BiscuitDisplay();
   private Button add = new Button("add");
   private Button del = new Button("delete");
   private Button find = new Button("find");
   private Button next = new Button("next");
   private Button prev = new Button("previous");
   private Label messages = new Label("Any system messages will appear here....");
   // We'll need an array to keep track of our collection
   private static final int MAX = 10;
   private Biscuit2[] biscuits = new Biscuit2[MAX];
   // pointers into the biscuit collection
   int lastBiscuit = -1;
   int current = -1;
   /**
   * Constructor
   */
   public BiscuitWindow()
   {
     // inner class to intercept window events
     addWindowListener ( new WindowAdapter()
     {
       // we are only interested in window closing
       public void windowClosing(WindowEvent e)
       {
         // Exit the system, 0 is a normal exit code
         System.exit(0);
       }
     } );
     // Helper method to set up the display
     makeDisplay();
   }
   /**
   * Helper method to set up the display
   */
   private void makeDisplay()
   {
     // set up the Biscuit display
     setLayout(new FlowLayout());
     add(display.getPanel());
     // Make a Panel for the buttons
     Panel buttonPanel = new Panel();
     buttonPanel.setLayout(new GridLayout(5,1));
     buttonPanel.add(add);
     buttonPanel.add(del);
     buttonPanel.add(find);
     buttonPanel.add(next);
     buttonPanel.add(prev);
     add(buttonPanel);
     // set up the button listeners
     add.addActionListener(this);
     del.addActionListener(this);
     find.addActionListener(this);
     next.addActionListener(this);
     prev.addActionListener(this);
     add(messages);
     setSize(500,200);
     setVisible(true);
   }
   /**
   * main method to call the Constructor
   */
   public static void main(String[] args)
   {
     BiscuitWindow theApp = new BiscuitWindow();
   }
   /**
   * Our old buddy, actionPerformed will detect the button presses
   *
   * @param the object that caused the event to occur
   */
   public void actionPerformed(ActionEvent e)
   {
     if (e.getSource() == add)
     {
       addBiscuit();
     }
     else if (e.getSource() == del)
     {
       messages.setText("My students will try their best");
     }
     else if (e.getSource() == find)
     {
       messages.setText("My brilliant programmers will whizz through this");
     }
     else if (e.getSource() == next)
     {
       messages.setText("My serfs will try to do this");
     }
     else if (e.getSource() == prev)
     {
       messages.setText("My best and brightest will have a go at this");
     }
   }
   public void addBiscuit()
   {
     // Check if the array is full
     if ( lastBiscuit < (MAX-1) )
     {
       lastBiscuit = lastBiscuit + 1;
       Biscuit2 b = display.getBiscuit();
       // check if a valid biscuit was got from display
       if (b != null)
       {
         biscuits[lastBiscuit] = b;
         messages.setText("Biscuit added");
       }
       else
       {
         messages.setText("Could not add the biscuit, check details");
       }
     }
     else
     {
       messages.setText("No more space to add biscuits");
     }
   }
}

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