ThreadedResourceObserver.cpp

00001 /**
00002  * @file    ThreadedResourceObserver.cpp
00003  * @brief   mbed CoAP DynamicResource Thread-based observer (implementation)
00004  * @author  Doug Anson/Chris Paola
00005  * @version 1.0
00006  * @see
00007  *
00008  * Copyright (c) 2014
00009  *
00010  * Licensed under the Apache License, Version 2.0 (the "License");
00011  * you may not use this file except in compliance with the License.
00012  * You may obtain a copy of the License at
00013  *
00014  *     http://www.apache.org/licenses/LICENSE-2.0
00015  *
00016  * Unless required by applicable law or agreed to in writing, software
00017  * distributed under the License is distributed on an "AS IS" BASIS,
00018  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00019  * See the License for the specific language governing permissions and
00020  * limitations under the License.
00021  */
00022  
00023  #include "ThreadedResourceObserver.h"
00024  
00025  #ifdef CONNECTOR_USING_THREADS
00026  // DEBUG
00027  //DigitalOut __threaded_led(LED2);
00028  #endif
00029  
00030  // constructor
00031  ThreadedResourceObserver::ThreadedResourceObserver(DynamicResource *resource,int sleep_time) : 
00032                                                             ResourceObserver(resource,sleep_time) 
00033  #ifdef CONNECTOR_USING_THREADS
00034                                                             ,m_observation_thread(&ThreadedResourceObserver::_observation_notifier,this) 
00035  #endif 
00036                                                             {
00037         this->setObserving(false);
00038         // DEBUG
00039         std::printf("ThreadedResourceObserver being used for %s (sleep_time=%d)\r\n",resource->getName().c_str(),sleep_time);
00040  }
00041  
00042  // destructor
00043  ThreadedResourceObserver::~ThreadedResourceObserver() {
00044      this->stopObservation();
00045  #ifdef CONNECTOR_USING_THREADS
00046      this->m_observation_thread.terminate();
00047  #endif
00048  }
00049  
00050  // notifier
00051  void ThreadedResourceObserver::_observation_notifier(void const *instance) {
00052  #ifdef CONNECTOR_USING_THREADS
00053      ThreadedResourceObserver *me = (ThreadedResourceObserver *)instance;
00054      while(true) {
00055          Thread::wait(me->getSleepTime());
00056          if (me->isObserving() == true && me->getResource() != NULL && nsdl_endpoint_is_registered() == true) {
00057              //
00058              // implementsObservation(): This switch denotes whether this threaded resource generates its own observations or relies on the heartbeat (time-based) mechanism.
00059              //   -- if resource itself doesn't implement it, then we can call notify() with the get() on each heartbeat of the threaded resource (see note below)
00060              //   -- otherwise, we let the resource itself call observe() as part of its observation implementation
00061              //
00062              // note: this is independent of whether the resource, when declared, is defined as an observable resource or not.  If not, then notify() wont be called 
00063              //       as there will be no observations for this resource regardless of this switch value. 
00064              //
00065              bool do_notify = !(me->getResource()->implementsObservation());
00066              me->getResource()->observe(do_notify);
00067              //__threaded_led = !__threaded_led;
00068          }
00069      }
00070  #endif
00071  }
00072 
00073  // begin observing...
00074  void ThreadedResourceObserver::beginObservation() {
00075      this->setObserving(true);
00076  }
00077  
00078  // stop observing...
00079  void ThreadedResourceObserver::stopObservation() {
00080      this->setObserving(false);
00081  }