procedural-vs-OOP/src/main/java/de/hsfulda/pmuw/procedural/CgolBoardProcedural.java

package de.hsfulda.pmuw.procedural;

import java.util.Calendar;
import java.util.Iterator;

import de.hsfulda.pmuw.oop.CellCreator;

public class CgolBoardProcedural {
  /** one alive to X dead */
  static final int ALIVE_CELLS_RATIO = 30;
  static final int BOARD_SIZE = 500;
  private boolean[][] board = new boolean[BOARD_SIZE][BOARD_SIZE];

  public void initialize() {
    createCells();
    System.out.println(String.format("cells created: %7s", BOARD_SIZE*BOARD_SIZE));
    System.out.println(String.format("active cells:  %7s", BOARD_SIZE*BOARD_SIZE));
    System.out.println(String.format("alive cells :  %7s", countAliveCells()));
  
  }

  private void createCells() {
    Iterator<Boolean> iterator = CellCreator.aliveList.iterator();
    for (int row = 0; row < board.length; row++)
      for (int col = 0; col < board[0].length; col++)
        board[row][col] = iterator.next();
  }

  public void nextGen() {
    boolean[][] nextGen = new boolean[BOARD_SIZE][BOARD_SIZE];
    for (int row = 0; row < board.length; row++)
      for (int col = 0; col < board[0].length; col++)
        nextGen[row][col] = newStateOfCell(row, col);
    board = nextGen;
  }

  private boolean newStateOfCell(int row, int col) {
    int countAliveNeighbors = countAliveNeighbors(row, col);
    return newState(countAliveNeighbors, board[row][col]);
  }

  private int countAliveNeighbors(int row, int col) {
    int aliveNeighbors = 0;
    for (int rOffset = -1; rOffset <= 1; rOffset++)
      for (int cOffset = -1; cOffset <= 1; cOffset++)
        aliveNeighbors += board[(row + rOffset + BOARD_SIZE) % BOARD_SIZE][(col + cOffset + BOARD_SIZE) % BOARD_SIZE]
            ? 1
            : 0;
    return aliveNeighbors - (board[row][col] ? 1 : 0);
  }

  private boolean newState(int aliveNeighbors, boolean isAlive) {
    return 3 == aliveNeighbors || (isAlive && 2 == aliveNeighbors);
  }

  private int countAliveCells() {
    int aliveCells = 0;
    for (int row = 0; row < board.length; row++)
      for (int col = 0; col < board[0].length; col++)
        aliveCells += board[row][col] ? 1 : 0;
    return aliveCells;
  }

  public static void main(String[] args) {
    long start = Calendar.getInstance().getTimeInMillis();
    CgolBoardProcedural cgolBoard = new CgolBoardProcedural();
    cgolBoard.initialize();
    long end = Calendar.getInstance().getTimeInMillis();
    System.out.println(String.format("initializing took: %sms", end - start));
    start = Calendar.getInstance().getTimeInMillis();
    int iterations = 1000;
    for (int i = 0; i < iterations; i++) {
      cgolBoard.nextGen();
      if (0 == i % 100)
        System.out.println(String.format("iteration %6d cells alife: %s , cells active %7s", i, cgolBoard.countAliveCells(),BOARD_SIZE*BOARD_SIZE));
    }
    end = Calendar.getInstance().getTimeInMillis();
    System.out.println(String.format("time spend for %d iterations: %sms\n\n", iterations, end - start));
  }
}