lottery.java

Beginning Java 2, SDK 1.4 Edition Exercise Code samples for this book

// Chapter 17 Exercise 5
/*
 The inner class, ControlAction, defines the Action objects for the control buttons.
 The control buttons are stored in instance members of the Lottery class so we can
 refer to them in the actionPErformed() method.
 The .gif files for the buttons are stored in the same directory as the Lottery.class file.
 */

// Applet to generate lottery entries
import javax.swing.JButton;
import javax.swing.JApplet;
import javax.swing.JPanel;
import javax.swing.BorderFactory;
import javax.swing.AbstractAction;
import javax.swing.JToolBar;
import javax.swing.ImageIcon;

import java.awt.GridLayout;
import java.awt.FlowLayout;
import java.awt.Dimension;
import java.awt.Container;
import java.awt.Color;
import java.awt.Cursor;
import java.awt.BorderLayout;
import java.awt.Component;

import java.util.Random;               // For random number generator
import java.util.Arrays;

import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.event.MouseEvent;
import java.awt.event.MouseAdapter;

import java.io.File;

public class Lottery extends JApplet {
  // Generate numberCount random selections from the values array
  static int[] getNumbers() {
    int[] numbers = new int[numberCount];  // Store for the numbers to be returned
    int candidate = 0;                     // Stores a candidate selection
    for(int i = 0; i < numberCount; i++) { // Loop to find the selections

      search:
      // Loop to find a new selection different from any found so far
      for(;;) {
        candidate = values[choice.nextInt(values.length)];
        for(int j = 0 ; j<i ; j++)         // Check against existing selections
          if(candidate==numbers[j])        // If it is the same
            continue search;               // get another random selection

        numbers[i] = candidate;            // Store the selection in numbers array
        break;                             // and go to find the next
      }
    }
    Arrays.sort(numbers);                  // Sort the selections
    return numbers;                        // Return the selections
  }

  // Initialize the applet
  public void init() {
    // Set up the lucky numbers buttons...
    // Set up the selection buttons
    Container content = getContentPane();
 //   content.setLayout(new GridLayout(0,1));  // Set the layout for the applet

    // Set up the panel to hold the lucky number buttons
    JPanel buttonPane = new JPanel();  // Add the pane containing numbers

    // Let's have a fancy panel border
    buttonPane.setBorder(BorderFactory.createTitledBorder(
                         BorderFactory.createEtchedBorder(Color.cyan,
                                                          Color.blue),
                                                          "Every One a Winner!"));

    int[] choices = getNumbers();            // Get initial set of numbers
    SelectionHandler selectionHandler = new SelectionHandler();    // Create the listener
    for(int i = 0; i<numberCount; i++) {
      luckyNumbers[i] = new Selection(choices[i]);
      luckyNumbers[i].addMouseListener(selectionHandler);
      buttonPane.add(luckyNumbers[i]);
    }
    content.add(buttonPane,BorderLayout.CENTER);

    // Add the toolbar to the content pane
    toolBar.setBorder(BorderFactory.createCompoundBorder(       // Toolbar border
                      BorderFactory.createLineBorder(Color.darkGray),
                      BorderFactory.createEmptyBorder(2,2,4,2)));   
    toolBar.setFloatable(false);             // Inhibit toolbar floating
    getContentPane().add(toolBar, BorderLayout.NORTH);

    // Add the three buttons to the toolbar
    newLuckyNumbers = toolBar.add(new ControlAction("numbers"));
    newLuckyNumbers.setBorder(BorderFactory.createRaisedBevelBorder());       

    color = toolBar.add(new ControlAction("color"));                     
    color.setBorder(BorderFactory.createRaisedBevelBorder());                    

    order = toolBar.add(new ControlAction("order"));                   
    order.setBorder(BorderFactory.createRaisedBevelBorder()); 
  }


  // Custom button showing lottery selection
  // Each button listens for its own events
  class Selection extends JButton {
  public Selection(int value) {
    super(Integer.toString(value));    // Call base constructor and set the label
    this.value = value;                // Save the value
    setBackground(startColor);
    setBorder(BorderFactory.createRaisedBevelBorder());    // Add button border
    setPreferredSize(new Dimension(80,20));

    // We no longer need the Selection object as the action listener
    // since the mouse handler deals with changes.
//    addActionListener(this);           // Button listens for itself
  }


  public void newSelection() {
    // Change this selection to a new selection
    int candidate = 0;
    for(;;) {                              // Loop to find a different selection
      candidate = values[choice.nextInt(values.length)];
      if(isCurrentSelection(candidate))    // If it is not different
        continue;                          // find another
      setValue(candidate);                 // We have one so set the button value
      return;
    }
  }

  // Get the value for this selection
  public int getValue() {
    return value;
  }

  // Set the value for the selection
  public void setValue(int value) {
    setText(Integer.toString(value));    // Set value as the button label
    this.value = value;                   // Save the value
  }

  // Check the value for the selection
  boolean hasValue(int possible) {
    return value==possible;               // Return true if equals current value 
  }

  // Check the current choices
  boolean isCurrentSelection(int possible) {
    for(int i = 0; i < numberCount; i++)         // For each button
      if(luckyNumbers[i].hasValue(possible))     // check against possible
        return true;                             // Return true for any =
    return false;                                // Otherwise return false 
  }

  private int value;                       // Value for the selection button
  }


  // Inner class to handle mouse events for the Selection buttons
  class SelectionHandler extends MouseAdapter {
  Cursor handCursor = new Cursor(Cursor.HAND_CURSOR);
  Cursor defaultCursor = new Cursor(Cursor.DEFAULT_CURSOR);

  // Handle mouse entering the selection button
  public void mouseEntered(MouseEvent e) {
    e.getComponent().setCursor(handCursor);    // Switch to hand cursor
  }

  // Handle mouse exiting the selection button
  public void mouseExited(MouseEvent e) {
    e.getComponent().setCursor(defaultCursor); // Change to default cursor
  }
    public void mousePressed(MouseEvent e) {
      ((Lottery.Selection)(e.getComponent())).newSelection();
    }
  }

  // Class defining action objects for control buttons on the toolbar
  class ControlAction extends AbstractAction {    
    // Constructor
    ControlAction(String name) {
      super(name);
      String iconFileName = name + ".gif";
      if(new File(iconFileName).exists())
        putValue(SMALL_ICON, new ImageIcon(iconFileName));
    }

    // Event handler
    public void actionPerformed(ActionEvent e) {
 
      // We can identify the component originating the action by
      // comparing the object return by getSource() method for the event object 
      // with our three ControlAction objects
      Object component = e.getSource();
      if(component == newLuckyNumbers) {
          int[] numbers = getNumbers();            // Get maxCount random numbers
          for(int i = 0; i < numberCount; i++)
            luckyNumbers[i].setValue(numbers[i]);  // Set the button values
      } else if(component == color) {
          Color color = new Color(
                flipColor.getRGB()^luckyNumbers[0].getBackground().getRGB());
          for(int i = 0; i < numberCount; i++)
            luckyNumbers[i].setBackground(color);  // Set the button colors        
      } else if(component == order) {
          int[] numbers = new int[numberCount];
          for(int i = 0; i < numberCount; i++)
            numbers[i] = luckyNumbers[i].getValue();    // Get the button values
          Arrays.sort(numbers);                         // and sort them
          for(int i = 0; i < numberCount; i++)
            luckyNumbers[i].setValue(numbers[i]);
      }
    }
  }

  final static int numberCount = 6;                   // Number of lucky numbers
  final static int minValue = 1;                      // Minimum in range
  final static int maxValue = 49;                     // Maximum in range
  static int[] values = new int[maxValue-minValue+1]; // Array of possible values
  static {                                            // Initialize array
    for(int i = 0 ; i<values.length ; i++)
      values[i] = i + minValue;
  }

  // An array of custom buttons for the selected numbers
  private Selection[] luckyNumbers = new Selection[numberCount]; 

  final public static int PICK_LUCKY_NUMBERS = 1;                // Select button ID
  final public static int COLOR = 2;                             // Color button ID
  final public static int ORDER = 3;                             // Order button ID
  
  // swap colors
  Color flipColor = new Color(Color.yellow.getRGB()^Color.red.getRGB()); 
  
  Color startColor = new Color(Color.yellow.getRGB());           // start color

  private static Random choice = new Random();         // Random number generator

  private JToolBar toolBar = new JToolBar();           // Toolbar for control buttons
  private JButton newLuckyNumbers, color ,order; // Toolbar buttons
}