code: public Axis getOrientationAxis() {
          final Axis axis;
          switch(getOrientation()) {
              case HORIZONTAL:
                  axis = Axis.X;
                  break;
              case VERTICAL:
                  axis = Axis.Y;
                  break;
              case STACK:
                  axis = Axis.Z;
                  break;
              default:
                  Log.w(TAG, "Unsupported orientation %s", mOrientation);
                  axis = Axis.X;
                  break;
          }
          return axis;
      }
docs: Get the axis along the orientation
  @return