Bouncing Coloring Ball Game(V1.0)

package javaapplication4;

import java.awt.*;

////////// BallModel
public class Ball {
    //... Constants
    
    
    final static int DIAMETER = 21;
    public Image buffer;                    // The off-screen image for double-buffering
    public Graphics bufferGraphics;         // A Graphics object for the buffer
    
    
    //... Instance variables
    private int m_x;           // x and y coordinates upper left
    private int m_y;
    private int typeColor;
    
    private int m_velocityX;   // Pixels to move each time move() is called.
    private int m_velocityY;
    
    private int m_rightBound;  // Maximum permissible x, y values.
    private int m_bottomBound;
    
    //======================================================== constructor
    public Ball(int x, int y, int velocityX, int velocityY) {
        m_x = x;
        m_y = y;
        m_velocityX = velocityX;
        m_velocityY = velocityY;
        
    }
    
    //======================================================== setBounds
    public void setBounds(int width, int height) {
        m_rightBound  = width  - DIAMETER;
        m_bottomBound = height - DIAMETER;
    }
    
    //============================================================== move
    public void move() {
        //... Move the ball at the give velocity.
        m_x += m_velocityX;
        m_y += m_velocityY;
        
        //... Bounce the ball off the walls if necessary.
        if (m_x < 0) {                  // If at or beyond left side
            typeColor=1;
            m_x         = 0;            // Place against edge and
            m_velocityX = -m_velocityX; // reverse direction.
            
        } else if (m_x > m_rightBound) { // If at or beyond right side
            m_x         = m_rightBound;    // Place against right edge.
            typeColor=2;
            m_velocityX = -m_velocityX;  // Reverse direction.
        }
        
        if (m_y < 0) {                 // if we're at top
            m_y       = 0;
            typeColor=3;
            m_velocityY = -m_velocityY;
            
        } else if (m_y > m_bottomBound) { // if we're at bottom
            m_y       =  m_bottomBound;
            typeColor=4;
            m_velocityY = -m_velocityY;
        }
    }
    
    //============================================================== draw
    public void draw(Graphics g) {
        if(typeColor==1){
            g.setColor(Color.BLUE);
            g.fillOval(m_x, m_y, DIAMETER, DIAMETER);
        }
        if(typeColor==2){
            g.setColor(Color.GREEN);
            g.fillOval(m_x, m_y, DIAMETER, DIAMETER);
        }
        if(typeColor==3){
            g.setColor(Color.YELLOW);
            g.fillOval(m_x, m_y, DIAMETER, DIAMETER);
        }
        if(typeColor==4){
            g.setColor(Color.RED);
            g.fillOval(m_x, m_y, DIAMETER, DIAMETER);
        }
        
    }
    
    //==== getDiameter, getX, getY
    public int  getDiameter() { return DIAMETER;}
    public int  getX()        { return m_x;}
    public int  getY()        { return m_y;}
    
    //===-======= setPosition
    public void setPosition(int x, int y) {
        m_x = x;
        m_y = y;
    }
}

/*
 * BallInBox.java

 */

package javaapplication4;


import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;

//////BouncingBall
public class BallInBox extends JPanel {
    //============================================== fields
    //... Instance variables representing the ball.
    private Ball m_ball         = new Ball(0, 0, 2, 3);
    private Ball mm_ball = new Ball(200, 80,2,3);
    
    //... Instance variables for the animiation
    private int   m_interval  = 35;  // Milliseconds between updates.
    private Timer m_timer;           // Timer fires to anmimate one step.
    
    //======= constructor
    /** Set panel size and creates timer. */
    public BallInBox() {
        setPreferredSize(new Dimension(200, 80));
        setBorder(BorderFactory.createLineBorder(Color.BLACK));
        m_timer = new Timer(m_interval, new TimerAction());
    }
    
    //========setAnimation
    /** Turn animation on or off.
     *@param turnOnOff Specifies state of animation.
     */
    public void setAnimation(boolean turnOnOff) {
        if (turnOnOff) {
            m_timer.start();  // start animation by starting the timer.
        } else {
            m_timer.stop();   // stop timer
        }
    }
 
    
    //===== paintComponent
    public void paintComponent(Graphics g) {
        super.paintComponent(g);  // Paint background, border
        m_ball.draw(g);  
        mm_ball.draw(g);// Draw the ball.
    }
    
    /////// inner listener class ActionListener
    class TimerAction implements ActionListener {
        //========== actionPerformed
        /** ActionListener of the timer.  Each time this is called,
         *  the ball's position is updated, creating the appearance of
         *  movement.
         *@param e This ActionEvent parameter is unused.
         */
        public void actionPerformed(ActionEvent e) {
            m_ball.setBounds(getWidth(), getHeight());
            m_ball.move();  // Move the ball.
            mm_ball.setBounds(getWidth(),getHeight());
            mm_ball.move();
            repaint();      // Repaint indirectly calls paintComponent.
        }
    }
}//endclass