A Simple Conway's Game Of Life Demo in Java

GameOfLifeDemo.java

public class GameOfLifeDemo {
	
	private static final int	HEIGHT = 10;
	private static final long	PERIOD = 120*1;
	
	public static void main(String[] args) throws InterruptedException {
		boolean [][] matrix = new boolean[HEIGHT][HEIGHT];
//		generateRandom(matrix);	// random values matrix
//		testGlider(matrix);		// test for Glider
		testTumbler(matrix);	// test for Tumbler
		
		while(true) {
			Thread.sleep(PERIOD);
			printMatrix(matrix);
			processLife(matrix);
			System.out.println("-----------------------------------------------------");
		}
	}
	
	private static void processLife(boolean[][] matrix) {
		boolean[][] tempMatrix = new boolean[matrix.length][matrix[0].length];
		copyMatrix(matrix, tempMatrix);
		
		// sweep the matrix
		for(int i = 0; i < HEIGHT; i++) {
			for(int j = 0; j < HEIGHT; j++) {
				// count alive neighboors
				int countAlive = 0;
				for(int k = i-1; k <= i+1; k++) {
					for(int t = j-1; t <= j+1; t++) {
						if((k == i && t == j) || (t < 0 || t >= HEIGHT) || (k < 0 || k >= HEIGHT) )
							continue;
						else {
							if(matrix[k][t]) {
								countAlive++;
							}
						}
					}
				}
				
				handleRules(tempMatrix, i, j, countAlive);
			}
		}
		
		copyMatrix(tempMatrix, matrix);
	}
	
	// rules
	// if cell have neighboors smaller than 1, die of loneliness
	// if cell have neighboors greater than 4, die of overpopulation
	// if only cell have 3 or 4 neighboors, live
	private static void handleRules(boolean[][] matrix, int i, int j, int countAlive) {
		if(countAlive <= 1 || countAlive >= 4)
			matrix[i][j] = false;
		else if(countAlive == 3 || countAlive == 4)
			matrix[i][j] = true;
	}
	
	private static void copyMatrix(boolean[][] src, boolean[][] dst) {
		for(int i = 0; i < HEIGHT; i++)
			System.arraycopy(src[i], 0, dst[i], 0, HEIGHT);
	}
	
	private static void printMatrix(boolean[][] matrix) {
		for(int i = 0; i < matrix.length; i++) {
			for(int j = 0; j < matrix[i].length; j++) {
				if(matrix[i][j] == true) {
					System.out.print('X');
				} else {
					System.out.print(' ');
				}
			}
			System.out.println();
		}
	}
	
	private static void generateRandom(boolean[][] matrix) {
		for(int i = 0; i < HEIGHT; i++)
			for(int j = 0; j < HEIGHT; j++)
				matrix[i][j] = Math.random() < 0.5;
	}
	
	/*
	 * Test Method for Generating a Glider
	 *    
	 *     X
	 *      X
	 *    XXX
	 * 
	 */
	private static void testGlider(boolean[][] matrix) {
		matrix[0][1] = true;
		
		matrix[1][2] = true;
		
		matrix[2][0] = true;
		matrix[2][1] = true;
		matrix[2][2] = true;
	}
	
	/*
	 * Test Method for Generating a Tumbler
	 *    
	 *      XX XX
	 *      XX XX
	 *       X X
	 *     X X X X
	 *     X X X X
	 *     XX   XX
	 * 
	 */
	private static void testTumbler(boolean[][] matrix) {
		matrix[0][2] = true;
		matrix[0][3] = true;
		matrix[0][5] = true;
		matrix[0][6] = true;
		
		matrix[1][2] = true;
		matrix[1][3] = true;
		matrix[1][5] = true;
		matrix[1][6] = true;
		
		matrix[2][3] = true;
		matrix[2][5] = true;
		
		matrix[3][1] = true;
		matrix[3][3] = true;
		matrix[3][5] = true;
		matrix[3][7] = true;
		
		matrix[4][1] = true;
		matrix[4][3] = true;
		matrix[4][5] = true;
		matrix[4][7] = true;
		
		matrix[5][1] = true;
		matrix[5][2] = true;
		matrix[5][6] = true;
		matrix[5][7] = true;
	}

}