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GloomcallerGloomcaller
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1 more chapter to go...
I was expecting this book to be just a "hey this is how you make things in Java so here you go" but it was quite interesting and it challenged me a few times. What started as me wanting to have something to go over when I have time has resulted in me finding programming more fun and rewarding.
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‎Chapter 16 - Reusing Classes/src/chapter16exercises/Automaton.java‎

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package chapter16exercises;
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import javax.swing.JFrame;
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public abstract class Automaton {
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protected GridCanvas grid;
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public abstract void update();
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private void mainloop(int rate) {
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while (true) {
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this.update();
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grid.repaint();
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try {
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Thread.sleep(1000 / rate);
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} catch (InterruptedException e) {
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}
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}
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}
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public void run(String title, int rate) {
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JFrame frame = new JFrame(title);
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frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
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frame.setResizable(false);
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frame.add(this.grid);
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frame.pack();
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frame.setVisible(true);
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this.mainloop(rate);
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}
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}

‎Chapter 16 - Reusing Classes/src/chapter16exercises/BriansBrain.java‎

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package chapter16exercises;
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public class BriansBrain extends Automaton {
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public BriansBrain(int rows, int cols, int cellSize) {
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grid = new GridCanvas(rows, cols, cellSize);
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}
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@Override
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public void update() {
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int rows = grid.numRows();
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int cols = grid.numCols();
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int[][] newStates = new int[rows][cols];
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for (int r = 0; r < rows; r++) {
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for (int c = 0; c < cols; c++) {
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Cell cell = grid.getCell(r, c);
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int neighbors = countAliveNeighbors(r, c);
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if (cell.isOn()) {
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newStates[r][c] = 2;
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} else if (cell.isOff() && neighbors == 2) {
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newStates[r][c] = 1;
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} else if (cell.isDying()) {
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newStates[r][c] = 0;
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} else {
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newStates[r][c] = cell.getState();
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}
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}
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}
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for (int r = 0; r < rows; r++) {
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for (int c = 0; c < cols; c++) {
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Cell cell = grid.getCell(r, c);
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cell.setState(newStates[r][c]);
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}
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}
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}
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private int countAliveNeighbors(int r, int c) {
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int count = 0;
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count += grid.test(r - 1, c - 1);
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count += grid.test(r - 1, c);
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count += grid.test(r - 1, c + 1);
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count += grid.test(r, c - 1);
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count += grid.test(r, c + 1);
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count += grid.test(r + 1, c - 1);
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count += grid.test(r + 1, c);
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count += grid.test(r + 1, c + 1);
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return count;
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}
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public static void main(String[] args) {
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String title = "Brian's Brain";
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BriansBrain game = new BriansBrain(50, 50, 10);
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game.run(title, 10);
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}
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}

‎Chapter 16 - Reusing Classes/src/chapter16exercises/Cell.java‎

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package chapter16exercises;
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import java.awt.Color;
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import java.awt.Graphics;
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public class Cell {
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private final int x;
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private final int y;
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private final int size;
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private int state;
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public static final int OFF = 0;
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public static final int ON = 1;
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public static final int DYING = 2;
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public static final Color[] COLORS = { Color.WHITE, Color.BLACK, Color.GRAY };
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public Cell(int x, int y, int size) {
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this.x = x;
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this.y = y;
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this.size = size;
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this.state = OFF;
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}
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public void draw(Graphics g) {
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g.setColor(COLORS[state]);
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g.fillRect(x + 1, y + 1, size - 1, size - 1);
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g.setColor(Color.LIGHT_GRAY);
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g.drawRect(x, y, size, size);
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}
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public boolean isOff() {
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return state == OFF;
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}
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public boolean isOn() {
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return state == ON;
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}
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public boolean isDying() {
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return state == DYING;
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}
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public void turnOff() {
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state = OFF;
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}
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public void turnOn() {
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state = ON;
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}
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public void setState(int state) {
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this.state = state;
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}
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public int getState() {
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return state;
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}
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}

‎Chapter 16 - Reusing Classes/src/chapter16exercises/Conway.java‎

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package chapter16exercises;
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public class Conway extends Automaton {
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public Conway() {
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grid = new GridCanvas(5, 10, 20);
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grid.turnOn(2, 1);
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grid.turnOn(2, 2);
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grid.turnOn(2, 3);
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grid.turnOn(1, 7);
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grid.turnOn(2, 7);
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grid.turnOn(3, 7);
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}
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private int countAlive(int r, int c) {
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int count = 0;
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count += grid.test(r - 1, c - 1);
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count += grid.test(r - 1, c);
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count += grid.test(r - 1, c + 1);
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count += grid.test(r, c - 1);
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count += grid.test(r, c + 1);
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count += grid.test(r + 1, c - 1);
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count += grid.test(r + 1, c);
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count += grid.test(r + 1, c + 1);
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return count;
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}
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private static void updateCell(Cell cell, int count) {
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if (cell.isOn()) {
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if (count < 2 || count > 3) {
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cell.turnOff();
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}
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} else {
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if (count == 3) {
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cell.turnOn();
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}
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}
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}
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private int[][] countNeighbors() {
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int rows = grid.numRows();
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int cols = grid.numCols();
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int[][] counts = new int[rows][cols];
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for (int r = 0; r < rows; r++) {
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for (int c = 0; c < cols; c++) {
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counts[r][c] = countAlive(r, c);
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}
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}
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return counts;
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}
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private void updateGrid(int[][] counts) {
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int rows = grid.numRows();
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int cols = grid.numCols();
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for (int r = 0; r < rows; r++) {
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for (int c = 0; c < cols; c++) {
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Cell cell = grid.getCell(r, c);
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updateCell(cell, counts[r][c]);
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}
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}
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}
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public void update() {
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int[][] counts = countNeighbors();
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updateGrid(counts);
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}
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public static void main(String[] args) {
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String title = "Conway's Game of Life";
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Conway game = new Conway();
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game.run(title, 2);
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}
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}

‎Chapter 16 - Reusing Classes/src/chapter16exercises/GridCanvas.java‎

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package chapter16exercises;
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import java.awt.Canvas;
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import java.awt.Graphics;
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public class GridCanvas extends Canvas {
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private Cell[][] array;
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public GridCanvas(int rows, int cols, int size) {
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array = new Cell[rows][cols];
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for (int r = 0; r < rows; r++) {
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int y = r * size;
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for (int c = 0; c < cols; c++) {
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int x = c * size;
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array[r][c] = new Cell(x, y, size);
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}
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}
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setSize(cols * size, rows * size);
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}
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public void draw(Graphics g) {
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for (Cell[] row : array) {
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for (Cell cell : row) {
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cell.draw(g);
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}
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}
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}
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public void paint(Graphics g) {
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draw(g);
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}
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public void update(Graphics g) {
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draw(g);
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}
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public int numRows() {
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return array.length;
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}
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public int numCols() {
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return array[0].length;
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}
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public Cell getCell(int r, int c) {
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return array[r][c];
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}
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public void turnOn(int r, int c) {
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array[r][c].turnOn();
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}
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public int test(int r, int c) {
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try {
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if (array[r][c].isOn()) {
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return 1;
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}
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} catch (ArrayIndexOutOfBoundsException e) {
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}
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return 0;
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}
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}

‎Chapter 16 - Reusing Classes/src/chapter16exercises/Langton.java‎

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package chapter16exercises;
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public class Langton extends Automaton {
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private int xpos;
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private int ypos;
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private int head;
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public Langton(int rows, int cols, int cellSize) {
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grid = new GridCanvas(rows, cols, cellSize);
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xpos = rows / 2;
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ypos = cols / 2;
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head = 0;
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}
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private void flipCell() {
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Cell cell = grid.getCell(xpos, ypos);
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if (cell.isOff()) {
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head = (head + 1) % 4;
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cell.turnOn();
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} else {
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head = (head + 3) % 4;
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cell.turnOff();
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}
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}
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private void moveAnt() {
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if (head == 0) {
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ypos -= 1;
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} else if (head == 1) {
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xpos += 1;
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} else if (head == 2) {
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ypos += 1;
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} else {
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xpos -= 1;
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}
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}
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@Override
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public void update() {
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flipCell();
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moveAnt();
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}
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public static void main(String[] args) {
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String title = "Langton's Ant";
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Langton game = new Langton(61, 61, 10);
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game.run(title, 500);
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}
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}

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