Pong

package pong;

import javax.swing.JFrame;

public class Pong extends JFrame
{
    public static int winWidth=900;
    public static int winHeight=600;

    public Pong()
    {
        add(new Window());

        setSize(winWidth, winHeight);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setVisible(true);
    }

    public static void main(String[] args)
    {
        Pong pong=new Pong();
    }
}

-

package pong;

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

public class Window extends JPanel implements ActionListener, KeyListener {

    Player player=new Player();
    Ball ball=new Ball();
    Computer computer=new Computer(this);

    public Window()
    {
        Timer timer=new Timer(25, this);
        timer.start();

        this.addKeyListener(this);
        this.setFocusable(true);
    }

    private void update()
    {
        player.update();
        ball.update();
        computer.update();

        ball.checkCollisionWith(player);
        ball.checkCollisionWith(computer);
        ball.wallHit();

    }

    public void paint(Graphics graphics)
    {
        graphics.setColor(Color.black);
        graphics.fillRect(0, 0, Pong.winWidth, Pong.winHeight);

        player.color(graphics);
        ball.color(graphics);
        computer.color(graphics);

        graphics.setColor(Color.gray);
        graphics.drawLine(0, 30, Pong.winWidth, 30);
        graphics.drawLine(200, 30, Pong.winWidth, 30);
    }

    public Ball getBall()
    {
        return ball;
    }

    public void actionPerformed(ActionEvent e)
    {
        update();
        repaint();
    }

    public void keyPressed(KeyEvent e)
    {
        if (e.getKeyCode()==KeyEvent.VK_UP)
        {
            player.setYVel(-5);
            if(player.returnY()<30)player.setYVel(0);
        }

        else if(e.getKeyCode()==KeyEvent.VK_DOWN)
        {
            player.setYVel(5);
            if(player.returnY()+40>Pong.winHeight-80)player.setYVel(0);
        }
    }

    public void keyReleased(KeyEvent e)
    {
        if (e.getKeyCode()==KeyEvent.VK_UP||e.getKeyCode()==KeyEvent.VK_DOWN)player.setYVel(0);
    }

    //Unused
    public void keyTyped(KeyEvent e) {
    }
}

-

package pong;

import java.awt.*;

public class Ball
{

    int x=Pong.winWidth/2;
    int y=Pong.winHeight/2;
    int xVel=-5;
    int yVel=5;
    int score=0;
    int compScore=0;

    public void update()
    {
        x+=xVel;
        y+=yVel;
        if (x<=-1)
        {
            xVel=5;
            compScore++;
        }
        else if ((x+20)>Pong.winWidth-6)
        {
            xVel=-5;
            score++;
        }
        if (y<=-1)yVel=5;
        else if ((y+20)>Pong.winHeight-28)yVel=-5;
    }

    private void reverseX()
    {
        xVel=-xVel;
    }

    private void reverseY()
    {
        yVel=-yVel;
    }

    public void checkCollisionWith(Player player)
    {
        if(x>player.returnX()&&x<player.returnX()+20)
        {
            if(y>player.returnY()&&y<player.returnY()+80)reverseX();
        }
    }

    public void checkCollisionWith(Computer computer)
    {
        if(x>computer.returnX()&&x<computer.returnX()+20)
        {
            if(y>computer.returnY()&&y<computer.returnY()+80)reverseX();
        }
    }

    public void wallHit()
    {
        if(y<30)reverseY();
    }

    public void color(Graphics graphics)
    {
        graphics.setColor(Color.white);
        graphics.fillOval(x, y, 20, 20);
        graphics.drawString("Your score: "+score, 5, 20);
        graphics.drawString("Computer's Score: "+compScore, 760, 20);
    }

    public int getX()
    {
        return x;
    }

    public int getY()
    {
        return y;
    }
}

-

package pong;

import java.awt.*;

public class Player
{

    int y=Pong.winHeight/2;
    int yVel=0;

    public void update()
    {
        y+=yVel;
    }

    public void color(Graphics graphics)
    {
        graphics.setColor(Color.red);
        graphics.fillRect(35, y, 20, 80);
    }

    public void setYVel(int speed)
    {
        yVel=speed;
    }

    public int returnX()
    {
        return 35;
    }

    public int returnY()
    {
        return y;
    }
}

-

package pong;

import java.awt.*;

public class Computer
{

    Window window;
    int y=Pong.winHeight/2;
    int yVel=0;

    public Computer(Window window)
    {
        this.window=window;
    }

    public void update()
    {
        if(window.getBall().getY()<y)yVel=-3;
        else if(window.getBall().getY()>y)yVel=3;
        y+=yVel;
    }

    public int returnX()
    {
        return Pong.winWidth-61;
    }

    public int returnY() {
        return y;
    }

    void color(Graphics graphics)
    {
        graphics.setColor(Color.blue);
        graphics.fillRect(Pong.winWidth-55, y, 20, 80);
    }
}