code: public void setInnerShadowEnabled(final boolean ENABLED) {
          if (null == innerShadowEnabled) {
              _innerShadowEnabled = ENABLED;
              fireUpdateEvent(REDRAW_EVENT);
          } else {
              innerShadowEnabled.set(ENABLED);
          }
      }
docs: Defines if an inner shadow should be drawn on the gauge
  background.
  
  @param ENABLED