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/* -*- C++ -*- */
/**
* @file EC_Gateway.h
*
* $Id$
*
* @author Carlos O'Ryan (coryan@cs.wustl.edu)
*
* Based on previous work by Tim Harrison (harrison@cs.wustl.edu) and
* other members of the DOC group. More details can be found in:
*
* http://doc.ece.uci.edu/~coryan/EC/index.html
*/
#ifndef TAO_EC_GATEWAY_H
#define TAO_EC_GATEWAY_H
#include "ace/pre.h"
#include "orbsvcs/Event/event_export.h"
#include "orbsvcs/RtecEventChannelAdminS.h"
#include "orbsvcs/RtecEventCommS.h"
#include "orbsvcs/Channel_Clients.h"
#include "ace/Map_Manager.h"
/**
* @class TAO_EC_Gateway
*
* @brief Event Channel Gateway
*
* There are several ways to connect several EC together, for
* instance:
* + A single class can use normal IIOP and connect to one EC as
* a supplier and to another EC as a consumer.
* + A class connects as a consumer and transmit the events using
* multicast, another class receives the multicast messages and
* transform them back into a push() call.
* This is an abstract class to represent all the different
* strategies for EC distribution.
*
*/
class TAO_RTEvent_Export TAO_EC_Gateway : public POA_RtecEventChannelAdmin::Observer
{
public:
/// Default constructor.
TAO_EC_Gateway (void);
/// Destructor
virtual ~TAO_EC_Gateway (void);
/// The gateway must disconnect from all the relevant event channels,
/// or any other communication media (such as multicast groups).
virtual void close (CORBA::Environment &env = TAO_default_environment ()) = 0;
/// Obtain and modify the observer handle.
void observer_handle (RtecEventChannelAdmin::Observer_Handle h);
RtecEventChannelAdmin::Observer_Handle observer_handle (void) const;
private:
RtecEventChannelAdmin::Observer_Handle handle_;
};
// ****************************************************************
/**
* @class TAO_EC_Gateway_IIOP
*
* @brief Event Channel Gateway using IIOP.
*
* This class mediates among two event channels, it connects as a
* consumer of events with a remote event channel, and as a supplier
* of events with the local EC.
* As a consumer it gives a QoS designed to only accept the events
* in which *local* consumers are interested.
* Eventually the local EC should create this object and compute its
* QoS in an automated manner; but this requires some way to filter
* out the peers registered as consumers, otherwise we will get
* loops in the QoS graph.
* It uses exactly the same set of events in the publications list
* when connected as a supplier.
*
* @note
* An alternative implementation would be to register with the
* remote EC as a supplier, and then filter on the remote EC, but
* one of the objectives is to minimize network traffic.
* On the other hand the events will be pushed to remote consumers,
* event though they will be dropped upon receipt (due to the TTL
* field); IMHO this is another suggestion that the EC needs to know
* (somehow) which consumers are truly its peers in disguise.
*
* @todo: The class makes an extra copy of the events, we need to
* investigate if closer collaboration with its collocated EC could
* be used to remove that copy.
*/
class TAO_RTEvent_Export TAO_EC_Gateway_IIOP : public TAO_EC_Gateway
{
public:
TAO_EC_Gateway_IIOP (void);
~TAO_EC_Gateway_IIOP (void);
/// To do its job this class requires to know the local and remote
/// ECs it will connect to,
void init (RtecEventChannelAdmin::EventChannel_ptr rmt_ec,
RtecEventChannelAdmin::EventChannel_ptr lcl_ec,
CORBA::Environment &ACE_TRY_ENV);
/// The channel is disconnecting.
void disconnect_push_supplier (CORBA::Environment & = TAO_default_environment ());
/// The channel is disconnecting.
void disconnect_push_consumer (CORBA::Environment & = TAO_default_environment ());
/// This is the Consumer side behavior, it pushes the events to the
/// local event channel.
void push (const RtecEventComm::EventSet &events,
CORBA::Environment & = TAO_default_environment ());
/// Disconnect and shutdown the gateway
int shutdown (CORBA::Environment & = TAO_default_environment ());
// The following methods are documented in the base class.
virtual void close (CORBA::Environment &env = TAO_default_environment ());
virtual void update_consumer (const RtecEventChannelAdmin::ConsumerQOS& sub,
CORBA::Environment &env = TAO_default_environment ())
ACE_THROW_SPEC ((CORBA::SystemException));
virtual void update_supplier (const RtecEventChannelAdmin::SupplierQOS& pub,
CORBA::Environment &env = TAO_default_environment ())
ACE_THROW_SPEC ((CORBA::SystemException));
private:
void close_i (CORBA::Environment &);
void update_consumer_i (const RtecEventChannelAdmin::ConsumerQOS& sub,
CORBA::Environment& env);
protected:
/// Do the real work in init()
void init_i (RtecEventChannelAdmin::EventChannel_ptr rmt_ec,
RtecEventChannelAdmin::EventChannel_ptr lcl_ec,
CORBA::Environment &ACE_TRY_ENV);
protected:
/// Lock to synchronize internal changes
TAO_SYNCH_MUTEX lock_;
/// How many threads are running push() we cannot make changes until
/// that reaches 0
CORBA::ULong busy_count_;
/**
* An update_consumer() message arrived *while* we were doing a
* push() the modification is stored <pub_>, if multiple
* update_consumer messages arrive only the last one is executed.
*/
int update_posted_;
RtecEventChannelAdmin::ConsumerQOS c_qos_;
/// The remote and the local EC, so we can reconnect when the list changes.
RtecEventChannelAdmin::EventChannel_var rmt_ec_;
RtecEventChannelAdmin::EventChannel_var lcl_ec_;
/// Our local and remote RT_Infos.
RtecBase::handle_t rmt_info_;
RtecBase::handle_t lcl_info_;
/// Our consumer personality....
/// If it is not 0 then we must deactivate the supplier
ACE_PushConsumer_Adapter<TAO_EC_Gateway_IIOP> consumer_;
int consumer_is_active_;
/// Our supplier personality....
/// If it is not 0 then we must deactivate the supplier
ACE_PushSupplier_Adapter<TAO_EC_Gateway_IIOP> supplier_;
int supplier_is_active_;
// We use a different Consumer_Proxy
typedef ACE_Map_Manager<RtecEventComm::EventSourceID,RtecEventChannelAdmin::ProxyPushConsumer_ptr,ACE_Null_Mutex> Consumer_Map;
typedef ACE_Map_Iterator<RtecEventComm::EventSourceID,RtecEventChannelAdmin::ProxyPushConsumer_ptr,ACE_Null_Mutex> Consumer_Map_Iterator;
/// We talk to the EC (as a supplier) using either an per-supplier
/// proxy or a generic proxy for the type only subscriptions.
Consumer_Map consumer_proxy_map_;
RtecEventChannelAdmin::ProxyPushConsumer_var default_consumer_proxy_;
/// We talk to the EC (as a consumer) using this proxy.
RtecEventChannelAdmin::ProxyPushSupplier_var supplier_proxy_;
};
#include "ace/post.h"
#endif /* ACE_EC_GATEWAY_H */
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