Harmeet.java

package com.zetcode;

import java.awt.Color;

import java.awt.Dimension;

import java.awt.Font;

import java.awt.FontMetrics;

import java.awt.Graphics;

import java.awt.Image;

import java.awt.Toolkit;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.awt.event.KeyAdapter;

import java.awt.event.KeyEvent;

import javax.swing.ImageIcon;

import javax.swing.JPanel;

import javax.swing.Timer;

public class Board extends JPanel implements ActionListener {

    private final int B_WIDTH = 300;

    private final int B_HEIGHT = 300;

    private final int DOT_SIZE = 10;

    private final int ALL_DOTS = 900;

    private final int RAND_POS = 29;

    private final int DELAY = 140;

    private final int x[] = new int[ALL_DOTS];

    private final int y[] = new int[ALL_DOTS];

    private int dots;

    private int apple_x;

    private int apple_y;

    private boolean leftDirection = false;

    private boolean rightDirection = true;

    private boolean upDirection = false;

    private boolean downDirection = false;

    private boolean inGame = true;

    private Timer timer;

    private Image ball;

    private Image apple;

    private Image head;

    public Board() {

        

        initBoard();

    }

    

    private void initBoard() {

        addKeyListener(new TAdapter());

        setBackground(Color.black);

        setFocusable(true);

        setPreferredSize(new Dimension(B_WIDTH, B_HEIGHT));

        loadImages();

        initGame();

    }

    private void loadImages() {

        ImageIcon iid = new ImageIcon("src/resources/dot.png");

        ball = iid.getImage();

        ImageIcon iia = new ImageIcon("src/resources/apple.png");

        apple = iia.getImage();

        ImageIcon iih = new ImageIcon("src/resources/head.png");

        head = iih.getImage();

    }

    private void initGame() {

        dots = 3;

        for (int z = 0; z < dots; z++) {

            x[z] = 50 - z * 10;

            y[z] = 50;

        }

        

        locateApple();

        timer = new Timer(DELAY, this);

        timer.start();

    }

    @Override

    public void paintComponent(Graphics g) {

        super.paintComponent(g);

        doDrawing(g);

    }

    

    private void doDrawing(Graphics g) {

        

        if (inGame) {

            g.drawImage(apple, apple_x, apple_y, this);

            for (int z = 0; z < dots; z++) {

                if (z == 0) {

                    g.drawImage(head, x[z], y[z], this);

                } else {

                    g.drawImage(ball, x[z], y[z], this);

                }

            }

            Toolkit.getDefaultToolkit().sync();

        } else {

            gameOver(g);

        }        

    }

    private void gameOver(Graphics g) {

        

        String msg = "Game Over";

        Font small = new Font("Helvetica", Font.BOLD, 14);

        FontMetrics metr = getFontMetrics(small);

        g.setColor(Color.white);

        g.setFont(small);

        g.drawString(msg, (B_WIDTH - metr.stringWidth(msg)) / 2, B_HEIGHT / 2);

    }

    private void checkApple() {

        if ((x[0] == apple_x) && (y[0] == apple_y)) {

            dots++;

            locateApple();

        }

    }

    private void move() {

        for (int z = dots; z > 0; z--) {

            x[z] = x[(z - 1)];

            y[z] = y[(z - 1)];

        }

        if (leftDirection) {

            x[0] -= DOT_SIZE;

        }

        if (rightDirection) {

            x[0] += DOT_SIZE;

        }

        if (upDirection) {

            y[0] -= DOT_SIZE;

        }

        if (downDirection) {

            y[0] += DOT_SIZE;

        }

    }

    private void checkCollision() {

        for (int z = dots; z > 0; z--) {

            if ((z > 4) && (x[0] == x[z]) && (y[0] == y[z])) {

                inGame = false;

            }

        }

        if (y[0] >= B_HEIGHT) {

            inGame = false;

        }

        if (y[0] < 0) {

            inGame = false;

        }

        if (x[0] >= B_WIDTH) {

            inGame = false;

        }

        if (x[0] < 0) {

            inGame = false;

        }

        

        if (!inGame) {

            timer.stop();

        }

    }

    private void locateApple() {

        int r = (int) (Math.random() * RAND_POS);

        apple_x = ((r * DOT_SIZE));

        r = (int) (Math.random() * RAND_POS);

        apple_y = ((r * DOT_SIZE));

    }

    @Override

    public void actionPerformed(ActionEvent e) {

        if (inGame) {

            checkApple();

            checkCollision();

            move();

        }

        repaint();

    }

    private class TAdapter extends KeyAdapter {

        @Override

        public void keyPressed(KeyEvent e) {

            int key = e.getKeyCode();

            if ((key == KeyEvent.VK_LEFT) && (!rightDirection)) {

                leftDirection = true;

                upDirection = false;

                downDirection = false;

            }

            if ((key == KeyEvent.VK_RIGHT) && (!leftDirection)) {

                rightDirection = true;

                upDirection = false;

                downDirection = false;

            }

            if ((key == KeyEvent.VK_UP) && (!downDirection)) {

                upDirection = true;

                rightDirection = false;

                leftDirection = false;

            }

            if ((key == KeyEvent.VK_DOWN) && (!upDirection)) {

                downDirection = true;

                rightDirection = false;

                leftDirection = false;

            }

        }

    }

}