namespace saga
{
  namespace messaging
  {
    enum state
    {
      Unknown = 0,
      New     = 1,
      Open    = 2, 
      Closed  = 3,
      Dropped = 4
    };

    class message : public saga::buffer
    {
      public:
        message (void);
        message (int            size);
        message (void         * data);
        message (saga::buffer   buf, 
                 int            size = -1);
       ~message (void);

       std::string get_sender (void);
       std::string get_id     (void);
    };


    class reliable_pubsub_endpoint : public saga::object
                                   , public saga::async
                                   , public saga::monitorable
    {
      // default properties for the reliable pubsub endpoint are:
      //   Topology    : PublishSubscriber
      //   Reliability : Reliable,        
      //   Atomicity   : ExactlyOnce,      
      //   Correctness : Verified,        
      //   Ordering    : Unordered        
      public:
        reliable_pubsub_endpoint (void);
        reliable_pubsub_endpoint (saga::object & obj); 
       ~reliable_pubsub_endpoint (void);

       // inspection
       saga::url get_url       (void);
       std::list <saga::url>
                 get_receivers (void);

       // management methods
       void      serve         (int       n_clients = -1);
       reliable_pubsub_endpoint  serve_once    (float     timout    = -1.0);
       void      connect       (float     timout    = -1.0);
       void      disconnect    (void);

       // I/O methods
       void      send          (message   m,
                                saga::url client    = "",
                                float     timout    = -1.0);

       int       test          (saga::url client    = "",
                                float     timout    = -1.0);
       
       message   receive       (saga::url client    = "",
                                float     timout    = -1.0) 
    };

    class unreliable_pubsub_endpoint ...
    class reliable_atomic_point2point_endpoint ...
    class reliable_atomic_point2point_endpoint ...
    class unreliable_point2point_endpoint ...
    ...
  }
}



//////////////////////////////////////////////////////////////////////
//
// application example
//

class geometry
{
  // ...
};

class geometry_message : public saga::messaging::message
{
  // define how the message is serialized into and deserialized from a message
  // buffer
};

void mapper_to_renderer (geometry geom)
{
  // Our set of specific endpoints does not offer any endpoint with the exact
  // properties we want, so we uses the closest match, which is the reliable
  // pubsub endpoint, which has Atomicity set to ExactlyOnce, instead of the
  // AtMostOnce we actually want.
  
  saga::messaging::reliable_pubsub_endpoint ep ("geom://remote.host.net:1234/renderer/");

  geometry_message gm (geom);
  
  ep.send (gm);
}