public void move()
  {
      if (position == 1 || position == 2)
      {
          x += dx;
          if (x <= 2) 
            x = 2;
          if (x >= Commons.PADDLE_RIGHT + Commons.NORMAL_PADDLE - 5 * scale)
            x = Commons.PADDLE_RIGHT + (Commons.NORMAL_PADDLE - 5 * scale);
      }
      else if (position == 3 || position == 4)
      {
          y += dy;
          if (y <= 2) 
            y = 2;
          if (y >= Commons.PADDLE_DOWN + Commons.NORMAL_PADDLE - 5 * scale - 27)
            y = Commons.PADDLE_DOWN + Commons.NORMAL_PADDLE - 5 * scale - 27;
      }
  }