.. _program_listing_file__tmp_ws_src_smacc2_smacc2_include_smacc2_client_base_components_cp_topic_subscriber.hpp:

Program Listing for File cp_topic_subscriber.hpp
================================================

|exhale_lsh| :ref:`Return to documentation for file <file__tmp_ws_src_smacc2_smacc2_include_smacc2_client_base_components_cp_topic_subscriber.hpp>` (``/tmp/ws/src/smacc2/smacc2/include/smacc2/client_base_components/cp_topic_subscriber.hpp``)

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

.. code-block:: cpp

   // Copyright 2021 RobosoftAI Inc.
   //
   // 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.
   
   /*****************************************************************************************************************
    *
    *   Authors: Pablo Inigo Blasco, Brett Aldrich
    *
    ******************************************************************************************************************/
   
   #pragma once
   #include <optional>
   #include <smacc2/client_bases/smacc_subscriber_client.hpp>
   #include <smacc2/component.hpp>
   #include <smacc2/smacc_signal.hpp>
   
   namespace smacc2
   {
   namespace components
   {
   using namespace smacc2::default_events;
   
   template <typename MessageType>
   class CpTopicSubscriber : public smacc2::ISmaccComponent
   {
   public:
     std::optional<int> queueSize;
   
     typedef MessageType TMessageType;
   
     CpTopicSubscriber() { initialized_ = false; }
   
     CpTopicSubscriber(std::string topicname) { topicName_ = topicname; }
   
     virtual ~CpTopicSubscriber() {}
   
     smacc2::SmaccSignal<void(const MessageType &)> onFirstMessageReceived_;
     smacc2::SmaccSignal<void(const MessageType &)> onMessageReceived_;
   
     std::function<void(const MessageType &)> postMessageEvent;
     std::function<void(const MessageType &)> postInitialMessageEvent;
   
     template <typename T>
     boost::signals2::connection onMessageReceived(
       void (T::*callback)(const MessageType &), T * object)
     {
       return this->getStateMachine()->createSignalConnection(onMessageReceived_, callback, object);
     }
   
     template <typename T>
     boost::signals2::connection onFirstMessageReceived(
       void (T::*callback)(const MessageType &), T * object)
     {
       return this->getStateMachine()->createSignalConnection(
         onFirstMessageReceived_, callback, object);
     }
   
     template <typename TOrthogonal, typename TSourceObject>
     void onOrthogonalAllocation()
     {
       this->postMessageEvent = [=](auto msg)
       {
         auto event = new EvTopicMessage<TSourceObject, TOrthogonal, MessageType>();
         event->msgData = msg;
         this->postEvent(event);
       };
   
       this->postInitialMessageEvent = [=](auto msg)
       {
         auto event = new EvTopicInitialMessage<TSourceObject, TOrthogonal, MessageType>();
         event->msgData = msg;
         this->postEvent(event);
       };
     }
   
     void onInitialize() override
     {
       if (!initialized_)
       {
         firstMessage_ = true;
   
         if (!queueSize) queueSize = 1;
   
         RCLCPP_INFO_STREAM(
           getLogger(), "[" << this->getName() << "] Subscribing to topic: " << topicName_);
   
         rclcpp::SensorDataQoS qos;
         if (queueSize) qos.keep_last(*queueSize);
   
         std::function<void(typename MessageType::SharedPtr)> fn = [this](auto msg)
         { this->messageCallback(*msg); };
   
         sub_ = this->getNode()->template create_subscription<MessageType>(topicName_, qos, fn);
         this->initialized_ = true;
       }
     }
   
   private:
     typename rclcpp::Subscription<MessageType>::SharedPtr sub_;
     bool firstMessage_;
     bool initialized_;
     std::string topicName_;
   
     void messageCallback(const MessageType & msg)
     {
       if (firstMessage_)
       {
         postInitialMessageEvent(msg);
         onFirstMessageReceived_(msg);
         firstMessage_ = false;
       }
   
       postMessageEvent(msg);
       onMessageReceived_(msg);
     }
   };
   }  // namespace components
   }  // namespace smacc2