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// -*- C++ -*-
// $Id$
// ============================================================================
//
// = LIBRARY
// TAO_LoadBalancing
//
// = FILENAME
// Round_Robin_Strategy.h
//
// = AUTHOR
// Ossama Othman <ossama@uci.edu>
//
// ============================================================================
#ifndef ROUND_ROBIN_STRATEGY_H
#define ROUND_ROBIN_STRATEGY_H
#include "ace/pre.h"
#include "LoadBalancing_Strategy.h"
#include "orbsvcs/LoadBalancingS.h"
#include "ace/Containers.h"
#include "ace/Synch.h"
#if !defined (ACE_LACKS_PRAGMA_ONCE)
# pragma once
#endif /* ACE_LACKS_PRAGMA_ONCE */
// Forward declarations
class TAO_LB_ReplicaProxy;
// @@ Ossama: is this the kind of data structure that you want to use
// in this case? I mean the iterator is invalidated on each insertion
// and extraction, the class is not thread safe and it is hard to find
// the element with the least load... Then again the number of
// servers should be small (say around 10), and additions/removals
// rare, so the data structure is probably not a real problem.
typedef ACE_Unbounded_Set<TAO_LB_ReplicaProxy *> TAO_LB_ReplicaProxySet;
typedef ACE_Unbounded_Set_Iterator<TAO_LB_ReplicaProxy *> TAO_LB_ReplicaProxySetIterator;
class TAO_LoadBalancing_Export TAO_LB_Round_Robin_Strategy : public TAO_LB_LoadBalancing_Strategy
{
// = TITLE
// Round Robin load balancing strategy
// = DESCRIPTION
// Simple load balancing strategy that causes requests to be
// forwarded to next Replica in the set, i.e. in a "round robin"
// fashion.
public:
TAO_LB_Round_Robin_Strategy (void);
// Constructor.
~TAO_LB_Round_Robin_Strategy (void);
// Destructor
// = The Load_Balancing_Strategy methods
virtual CORBA::Object_ptr replica (CORBA_Environment &ACE_TRY_ENV)
ACE_THROW_SPEC ((CORBA::SystemException));
virtual int insert (TAO_LB_ReplicaProxy *);
virtual int remove (TAO_LB_ReplicaProxy *);
private:
TAO_LB_ReplicaProxySet proxies_;
// Set containing the ReplicaProxy servants.
ACE_Unbounded_Set_Iterator<TAO_LB_ReplicaProxy *> next_replica_;
TAO_SYNCH_MUTEX lock_;
// Lock used to ensure access to state within this class is atomic.
};
#include "ace/post.h"
#endif /* ROUND_ROBIN_STRATEGY_H */
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