code: public <E> E get(Class<E> clss) {
  	testControllerClass(clss);
  	synchronized (controllers) {
  	  for (Controller controller : controllers) {
  		if (clss.isAssignableFrom(controller.getClass())) {
  		  return clss.cast(controller);
  		}
  	  }
  	}
  	return null;
    }
docs: Gets the controller of a specific class.
  
  @param clss
  the controller's class
  @return the controller or <code>NULL</code> if its not exist.