code: private void onJoinCall(JoinCall message, ActorRef self, ActorRef sender) {
          connectionMode = message.getConnectionMode();
          // Tell call to join conference by passing reference to the media mixer
          final JoinConference join = new JoinConference(this.cnfEndpoint, connectionMode, message.getSid());
          message.getCall().tell(join, sender);
      }
docs: /*private void onMediaGroupStateChanged(MediaGroupStateChanged message, ActorRef self, ActorRef sender) throws Exception {
  switch (message.state()) {
  case ACTIVE:
  if (is(creatingMediaGroup)) {
  fsm.transition(message, gettingCnfMediaResourceController);
  }
  break;
  
  case INACTIVE:
  if (is(creatingMediaGroup)) {
  this.fail = Boolean.TRUE;
  fsm.transition(message, failed);
  } else if (is(stopping)) {
  Stop media group actor
  this.mediaGroup.tell(new StopObserving(self), self);
  context().stop(mediaGroup);
  this.mediaGroup = null;
  
  Move to next state
  if (this.mediaGroup == null && this.cnfEndpoint == null) {
  this.fsm.transition(message, fail ? failed : inactive);
  }
  }
  break;
  
  default:
  break;
  }
  }