so_5/chstate/main.cpp

/*
 * A sample of the simpliest agent which has several states.
 * The agent uses different handlers for the same message.
 * At the beginning of its work agent initiates a periodic message.
 * Then agent handles this messages and switches from one state
 * to another.
 *
 * A work of the SObjectizer Environment is finished after the agent
 * switched to the final state.
 *
 * State switching is fixed by a state listener.
 */

#if defined( _MSC_VER )
  #if defined( __clang__ )
    #pragma clang diagnostic ignored "-Wreserved-id-macro"
  #endif
  #define _CRT_SECURE_NO_WARNINGS
#endif

#include <iostream>
#include <time.h>

// Main SObjectizer header file.
#include <so_5/all.hpp>

// Periodic message.
class msg_periodic final : public so_5::signal_t {};

// State listener for fixing state changes.
class state_monitor_t final : public so_5::agent_state_listener_t
{
  const std::string m_type_hint;

  public:
    state_monitor_t( const std::string & type_hint )
      : m_type_hint( type_hint )
    {}

    void changed(
      so_5::agent_t &,
      const so_5::state_t & state ) noexcept override
    {
      std::cout << m_type_hint << " agent changed state to "
        << state.query_name()
        << std::endl;
    }
};

// A sample agent class.
class a_state_swither_t final : public so_5::agent_t
{
    // Agent states.
    const state_t st_1{ this, "state_1" };
    const state_t st_2{ this, "state_2" };
    const state_t st_3{ this, "state_3" };
    const state_t st_shutdown{ this, "shutdown" };

  public:
    a_state_swither_t( context_t ctx )
      : so_5::agent_t{ ctx }
    {}

    // Definition of the agent for SObjectizer.
    void so_define_agent() override;

    // Reaction to start into SObjectizer.
    void so_evt_start() override;

    // Message handler for the default state.
    void evt_handler_default( mhood_t<msg_periodic> );

    // Message handler for the state_1.
    void evt_handler_1( mhood_t<msg_periodic> );

    // Message handler for the state_2.
    void evt_handler_2( mhood_t<msg_periodic> );

    // Message handler for the state_3.
    void evt_handler_3( mhood_t<msg_periodic> );

    // Message handler for the shutdown_state.
    void evt_handler_shutdown( mhood_t<msg_periodic> );

  private:
    // Timer event id.
    // If we do not store it the periodic message will
    // be canceled automatically.
    so_5::timer_id_t m_timer_id;

    // Helper method for showing that event handler is called.
    void show_event_invocation( const char * event_name );
};

void a_state_swither_t::so_define_agent()
{
  // Message subsription.
  so_subscribe_self()
    .event( &a_state_swither_t::evt_handler_default );

  so_subscribe_self().in( st_1 )
    .event( &a_state_swither_t::evt_handler_1 );

  so_subscribe_self().in( st_2 )
    .event( &a_state_swither_t::evt_handler_2 );

  so_subscribe_self().in( st_3 )
    .event( &a_state_swither_t::evt_handler_3 );

  so_subscribe_self().in( st_shutdown )
    .event( &a_state_swither_t::evt_handler_shutdown );
}

void a_state_swither_t::so_evt_start()
{
  show_event_invocation( "so_evt_start()" );

  // Periodic message should be initiated.
  m_timer_id = so_5::send_periodic< msg_periodic >(
      *this,
      std::chrono::seconds( 1 ),
      std::chrono::seconds( 1 ) );
}

void a_state_swither_t::evt_handler_default( mhood_t<msg_periodic> )
{
  show_event_invocation( "evt_handler_default" );

  // Switching to the next state.
  so_change_state( st_1 );
}

void a_state_swither_t::evt_handler_1( mhood_t<msg_periodic> )
{
  show_event_invocation( "evt_handler_1" );

  // Switching to the next state.
  so_change_state( st_2 );
}

void a_state_swither_t::evt_handler_2( mhood_t<msg_periodic> )
{
  show_event_invocation( "evt_handler_2" );

  // Switching to the next state.
  so_change_state( st_3 );
}

void a_state_swither_t::evt_handler_3( mhood_t<msg_periodic> )
{
  show_event_invocation( "evt_handler_3" );

  // Switching to the next state.
  so_change_state( st_shutdown );
}

void a_state_swither_t::evt_handler_shutdown( mhood_t<msg_periodic> )
{
  show_event_invocation( "evt_handler_3" );

  // Switching to the default state.
  so_change_state( so_default_state() );

  // Finishing SObjectizer's work.
  std::cout << "Stop sobjectizer..." << std::endl;
  so_environment().stop();
}

void a_state_swither_t::show_event_invocation( const char * event_name )
{
  time_t t = time( nullptr );
  std::cout << asctime( localtime( &t ) )
    << event_name << ", state: " << so_current_state().query_name()
    << std::endl;
}

// A state listener.
state_monitor_t g_state_monitor( "nondestroyable_listener" );

// The SObjectizer Environment initialization.
void init( so_5::environment_t & env )
{
  auto ag = env.make_agent< a_state_swither_t >();

  // Adding the state listener. Its lifetime is not controlled by the agent.
  ag->so_add_nondestroyable_listener( g_state_monitor );

  // Adding another state listener.
  // Its lifetime is controlled by the agent.
  ag->so_add_destroyable_listener(
    std::make_unique< state_monitor_t >( "destroyable_listener" ) );

  // Creating and registering a cooperation.
  env.register_agent_as_coop( std::move(ag) );
}

int main()
{
  try
  {
    so_5::launch( &init );
  }
  catch( const std::exception & ex )
  {
    std::cerr << "Error: " << ex.what() << std::endl;
    return 1;
  }

  return 0;
}