so_5/dispatcher_hello/main.cpp

/*
 * Demonstration of very simple case for dispatchers.
 */

#include <iostream>
#include <sstream>

#include <so_5/all.hpp>

// Sample coordinator.
// Works on the default dispatcher.
// Receives messages from children agents.
// Finishes sample when all messages are received.
class a_coordinator_t final : public so_5::agent_t
{
public :
  a_coordinator_t( context_t ctx ) : so_5::agent_t( ctx )
  {}

  void so_define_agent() override
  {
    // Just one message must be handled in the default agent state.
    so_default_state().event( [this]( const std::string & msg ) {
        std::cout << "hello: " << msg << std::endl;

        // Work must be stopped if all messages are received.
        if( 0 == (--m_remaining_messages) )
          so_deregister_agent_coop_normally();
      } );
  }

  void so_evt_start() override
  {
    // Cooperation must be created at the start of agent's work.

    create_first_child_coop();
    create_second_child_coop();
  }

private :
  unsigned int m_remaining_messages = 6;

  void create_first_child_coop()
  {
    // The first cooperation will use one_thread dispatcher.
    auto disp = so_5::disp::one_thread::make_dispatcher(
        so_environment() );
    auto coop = so_5::create_child_coop(
        // This agent will be parent for new cooperation.
        *this,
        // The main dispatcher for the new cooperation is
        // one_thread dispatcher.
        disp.binder() );

    fill_and_register_coop( std::move( coop ), "one_thread" );
  }

  void create_second_child_coop()
  {
    // The second cooperation will use active_obj dispatcher.
    auto disp = so_5::disp::active_obj::make_dispatcher(
        so_environment() );
    auto coop = so_5::create_child_coop(
        // This agent will be parent for new cooperation.
        *this,
        // The main dispatcher for the new cooperation is
        // active_obj dispatcher.
        disp.binder() );

    fill_and_register_coop( std::move( coop ), "active_obj" );
  }

  void fill_and_register_coop(
    so_5::coop_unique_holder_t coop,
    const std::string & agent_name_prefix )
  {
    // Type of agent to be used in child coop.
    class demo_agent_t final : public so_5::agent_t {
      const so_5::mbox_t m_mbox;
      const std::string m_agent_name;
    public :
      demo_agent_t(
        context_t ctx,
        so_5::mbox_t mbox,
        std::string agent_name )
        : so_5::agent_t{ std::move(ctx) }
        , m_mbox{ std::move(mbox) }
        , m_agent_name{ std::move(agent_name) }
      {}

      void so_evt_start() override
      {
        // Hello message must contain agent name and thread id.
        std::ostringstream ss;
        ss << m_agent_name << " on thread: "
          << std::this_thread::get_id();

        // Coordinator should receive a hello message.
        so_5::send< std::string >( m_mbox, ss.str() );
      }
    };

    // Coordinator's mbox to which hello messages must be sent.
    const auto mbox = so_direct_mbox();

    for( int i = 0; i != 3; ++i )
    {
      coop->make_agent< demo_agent_t >(
          mbox,
          agent_name_prefix + "-" + std::to_string( i ) );
    }

    so_environment().register_coop( std::move( coop ) );
  }
};

int main()
{
  try
  {
    so_5::launch(
      []( so_5::environment_t & env ) {
        // Coordinator agent will work on the default dispatcher.
        env.register_agent_as_coop(
            env.make_agent< a_coordinator_t >() );
      } );

    return 0;
  }
  catch( const std::exception & x )
  {
    std::cerr << "*** Exception caught: " << x.what() << std::endl;
  }

  return 2;
}