📄 lottery.java
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// Applet to generate lottery entries
import javax.swing.JButton;
import javax.swing.JApplet;
import javax.swing.JPanel;
import javax.swing.BorderFactory;
import java.awt.GridLayout;
import java.awt.FlowLayout;
import java.awt.Dimension;
import java.awt.Container;
import java.awt.Color;
import java.util.Random; // For random number generator
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
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
}
}
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
for(int i = 0; i<numberCount; i++)
{
luckyNumbers[i] = new Selection(choices[i]);
buttonPane.add(luckyNumbers[i]);
}
content.add(buttonPane);
// Set up the control buttons...
// Add the pane containing control buttons
JPanel controlPane = new JPanel(new FlowLayout(FlowLayout.CENTER, 5, 10));
// Add the two control buttons
JButton button; // A button variable
Dimension buttonSize = new Dimension(100,20); // Button size
controlPane.add(button = new JButton("Lucky Numbers!"));
button.setBorder(BorderFactory.createRaisedBevelBorder());
button.addActionListener(new HandleControlButton(PICK_LUCKY_NUMBERS));
button.setPreferredSize(buttonSize);
controlPane.add(button = new JButton("Color"));
button.setBorder(BorderFactory.createRaisedBevelBorder());
button.addActionListener(new HandleControlButton(COLOR));
button.setPreferredSize(buttonSize);
content.add(controlPane);
}
// Custom button showing lottery selection
// Each button listens for its own events
class Selection extends JButton implements ActionListener
{
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));
addActionListener(this); // Button listens for itself
}
// Handle selection button event
public void actionPerformed(ActionEvent e)
{
// 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;
}
}
// 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
}
// Class defining a handler for a control button
class HandleControlButton implements ActionListener
{
// Constructor...
private int buttonID;
// Constructor
public HandleControlButton(int buttonID)
{
this.buttonID = buttonID; // Store the button ID
}
// Handle button click
public void actionPerformed(ActionEvent e)
{
switch(buttonID)
{
case PICK_LUCKY_NUMBERS:
int[] numbers = getNumbers(); // Get maxCount random numbers
for(int i = 0; i < numberCount; i++)
luckyNumbers[i].setValue(numbers[i]); // Set the button values
break;
case 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
break;
}
}
}
final static int numberCount = 6; // Number of lucky numbers
final static int minValue = 1; // Minimum in range
final static int maxValue = 33; // 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
// 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
}
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