public boolean move(Direction direction)
    {
        int newPosition = direction.getNextPosition(this);
        MovedEmptySlot emptySlot = new MovedEmptySlot(emptySlotPos, newPosition);
        if (newPosition < 0) {
            return false;
        }
        else {
            arrayID[emptySlotPos] = newPosition;
            arrayID[newPosition] = -1;
            emptySlotPos = arrayID[newPosition];
            movesPerformed.push(direction);
            this.notifyObservers(emptySlot);
            return true;
        }
    }