code: private void invokeChainedMethod(Event event) {
          Queue<MethodWrapper> queue = conversationQueueMap.get(event.getSender().getId());
  
          if (queue != null && !queue.isEmpty()) {
              MethodWrapper methodWrapper = queue.peek();
  
              try {
                  EventType[] eventTypes = methodWrapper.getMethod().getAnnotation(Controller.class).events();
                  for (EventType eventType : eventTypes) {
                      if (eventType.name().equalsIgnoreCase(event.getType().name())) {
                          methodWrapper.getMethod().invoke(this, event);
                          return;
                      }
                  }
              } catch (Exception e) {
                  logger.error("Error invoking chained method: ", e);
              }
          }
      }
docs: Invoke the appropriate method in a conversation.
  
  @param event received from facebook