direction.java

一个java的游戏程序

/**
 * Sets the directions, used mainly on the board, and crates the posibility for
 * finding the opposite direction.
 */
class Direction {
    final static  int NORTH;
    final static  int NORTHEAST;
    final static  int EAST;
    final static  int SOUTHEAST;
    final static  int SOUTH;
    final static  int SOUTHWEST;
    final static  int WEST;
    final static  int NORTHWEST;

    final static Direction north;
    final static Direction northeast;
    final static Direction east;
    final static Direction south;
    final static Direction southeast;
    final static Direction southwest;
    final static Direction west;
    final static Direction northwest;
    
    final static Direction all[];

    static{ 
      NORTH = 0;
      NORTHEAST = 1;
      EAST = 2;
      SOUTHEAST = 3;
      SOUTH = 4;
      SOUTHWEST = 5;
      WEST = 6;
      NORTHWEST = 7;

      north     = new Direction(NORTH, 0, 1);
      northeast = new Direction(NORTHEAST, 1, 1);
      east      = new Direction(EAST, 1, 0);
      southeast = new Direction(SOUTHEAST, 1, -1);
      south     = new Direction(SOUTH, 0, -1);
      southwest = new Direction(SOUTHWEST, -1, -1);
      west      = new Direction(WEST, -1, 0);
      northwest = new Direction(NORTHWEST, -1, 1);

      all = new Direction[8];

      all[NORTH]     = north;
      all[NORTHEAST] = northeast;
      all[EAST]      = east;
      all[SOUTHEAST] = southeast;
      all[SOUTH]     = south;
      all[SOUTHWEST] = southwest;
      all[WEST]      = west;
      all[NORTHWEST] = northwest;
    }
  
  
  /**
   * Returns the opposite direction from the one given as a parameter,
   * when the int given does not represent a valid direction a default
   * negative number is returned.
   */
  public static int opposite(int direction)
    {
	if(direction == NORTH)
	    return SOUTH;
	else if(direction == SOUTH)
	    return NORTH;
	else if(direction == NORTHWEST)
	    return SOUTHEAST;
	else if(direction == SOUTHEAST)
	    return NORTHWEST;
	else if(direction == NORTHEAST)
	    return SOUTHWEST;
	else if(direction == SOUTHWEST)
	    return NORTHEAST;
	else if(direction == WEST)
	    return EAST;
	else if(direction == EAST)
	    return WEST;
	else
	    return -1;
    }

    private int _direction;
    private int _x;
    private int _y;

    public Direction(int direction, int x, int y)
    {
	_direction = direction;
	_x = x;
	_y = y;
    }

    public GridCell go(GridCell cell)
    {
	return cell.getNeighbour(_direction);
    }

    public Direction opposite()
    {
	return all[Direction.opposite(_direction)];
    }

    public Direction next()
    {
	return all[(_direction + 1) % 8];
    }

    public int x()
    {
	return _x;
    }

    public int y()
    {
	return _y;
    }

}