.. _program_listing_file_include_libstatistics_collector_topic_statistics_collector_received_message_period.hpp:

Program Listing for File received_message_period.hpp
====================================================

|exhale_lsh| :ref:`Return to documentation for file <file_include_libstatistics_collector_topic_statistics_collector_received_message_period.hpp>` (``include/libstatistics_collector/topic_statistics_collector/received_message_period.hpp``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   // Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
   //
   // Licensed under the Apache License, Version 2.0 (the "License");
   // you may not use this file except in compliance with the License.
   // You may obtain a copy of the License at
   //
   //     http://www.apache.org/licenses/LICENSE-2.0
   //
   // Unless required by applicable law or agreed to in writing, software
   // distributed under the License is distributed on an "AS IS" BASIS,
   // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   // See the License for the specific language governing permissions and
   // limitations under the License.
   
   #ifndef LIBSTATISTICS_COLLECTOR__TOPIC_STATISTICS_COLLECTOR__RECEIVED_MESSAGE_PERIOD_HPP_
   #define LIBSTATISTICS_COLLECTOR__TOPIC_STATISTICS_COLLECTOR__RECEIVED_MESSAGE_PERIOD_HPP_
   
   #include <chrono>
   #include <mutex>
   #include <string>
   
   #include "constants.hpp"
   #include "libstatistics_collector/topic_statistics_collector/topic_statistics_collector.hpp"
   
   #include "rcl/time.h"
   
   namespace libstatistics_collector
   {
   namespace topic_statistics_collector
   {
   
   constexpr const int64_t kUninitializedTime{0};
   
   template<typename T>
   class ReceivedMessagePeriodCollector : public TopicStatisticsCollector<T>
   {
   public:
     ReceivedMessagePeriodCollector()
     {
       ResetTimeLastMessageReceived();
     }
   
     virtual ~ReceivedMessagePeriodCollector() = default;
   
     void OnMessageReceived(const T & received_message, const rcl_time_point_value_t now_nanoseconds)
     override RCPPUTILS_TSA_REQUIRES(mutex_)
     {
       std::unique_lock<std::mutex> ulock{mutex_};
   
       (void) received_message;
   
       if (time_last_message_received_ == kUninitializedTime) {
         time_last_message_received_ = now_nanoseconds;
       } else {
         const std::chrono::nanoseconds nanos{now_nanoseconds - time_last_message_received_};
         const auto period = std::chrono::duration<double, std::milli>(nanos);
         time_last_message_received_ = now_nanoseconds;
         collector::Collector::AcceptData(static_cast<double>(period.count()));
       }
     }
   
     std::string GetMetricName() const override
     {
       return topic_statistics_constants::kMsgPeriodStatName;
     }
   
     std::string GetMetricUnit() const override
     {
       return topic_statistics_constants::kMillisecondUnitName;
     }
   
   protected:
     bool SetupStart() override
     {
       ResetTimeLastMessageReceived();
       return true;
     }
   
     bool SetupStop() override
     {
       return true;
     }
   
   private:
     void ResetTimeLastMessageReceived()
     {
       time_last_message_received_ = kUninitializedTime;
     }
   
     rcl_time_point_value_t time_last_message_received_ RCPPUTILS_TSA_GUARDED_BY(mutex_) =
       kUninitializedTime;
     mutable std::mutex mutex_;
   };
   
   }  // namespace topic_statistics_collector
   }  // namespace libstatistics_collector
   
   #endif  // LIBSTATISTICS_COLLECTOR__TOPIC_STATISTICS_COLLECTOR__RECEIVED_MESSAGE_PERIOD_HPP_