uni-lab/java-lab/SENKU-GAME/src/Direction.java

public class Direction {

    public static final Direction UP = new Direction(0, -1);
    public static final Direction RIGHT = new Direction(1, 0);
    public static final Direction DOWN = new Direction(0, 1);
    public static final Direction LEFT = new Direction(-1, 0);

    public static final Direction[] ALL = new Direction[]{UP, RIGHT, DOWN, LEFT};

    private final int dx;
    private final int dy;

    private Direction(int dx, int dy) {
        this.dx = dx;
        this.dy = dy;
    }

    public Position apply(Position from) {
        return new Position(from.getX() + dx,
                            from.getY() + dy);
    }

    public Position apply2Times(Position from) {
        return new Position(from.getX() + dx * 2,
                            from.getY() + dy * 2);
    }
}