code: public void registerController(final Class<?> mappedControllerClass, final ViewController controller) {
          controllers.put(mappedControllerClass, controller);
          if (Strings.isNotEmpty(controller.getViewId())) {
              parser.getData().addActorConsumer(SCREEN_TRANSITION_ACTION_PREFIX + controller.getViewId(),
                      new ScreenTransitionAction(this, mappedControllerClass));
          }
      }
docs: Allows to manually register a managed controller. For internal use mostly.
  
  @param mappedControllerClass class with which the controller is accessible. This does not have to be controller's
  actual class.
  @param controller controller implementation, managing a single view.