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// This may look like C, but it's really -*- C++ -*-
// $Id$
//================================================================================
//
// = LIBRARY
// TAO/examples/POA/Loader
//
// = FILENAME
// Servant_Locator.h
//
// = DESCRIPTION
// Defines a ServantLocator_i class , used with a POA having
// a NON_RETAIN policy.
//
// = AUTHOR
// Kirthika Parameswaran <kirthika@cs.wustl.edu>
//
//==================================================================================
#include "ace/OS.h"
#ifndef SERVANT_LOCATOR_H
#define SERVANT_LOCATOR_H
#include "tao/corba.h"
#include "ace/DLL.h"
class ServantLocator_i : public POA_PortableServer::ServantLocator
{
// = TITLE
// This class is used by a POA with USE_SERVANT_MANAGER and
// NON_RETAIN policy.
//
// = DESCRIPTION
// This class defines the Servant Locator interface of the Servant
// Manager. It is invoked when the POA has an USE_SERVANT_MANAGER
// policy and a servant_retention policy of NON_RETAIN type.
public:
typedef PortableServer::Servant
(*SERVANT_FACTORY) (const PortableServer::ObjectId &oid,
PortableServer::POA_ptr poa,
CORBA::ORB_ptr orb);
// This typedef is used to typecast the void* obtained when finding
// a symbol in the dll. Invoking the function pointer obtained would
// get a servant.
typedef void
(*SERVANT_GARBAGE_COLLECTOR) (const PortableServer::ObjectId &oid,
PortableServer::POA_ptr,
PortableServer::Servant servant);
// This typedef is used to obtain the garbage_collection_function symbol
// in the dll. Invoking the function pointer obtained would then destroy
// the servant.
ServantLocator_i (CORBA::ORB_ptr orb,
const char *dllname,
const char *factory_function,
const char *garbage_collection_function);
// Constructor.
virtual PortableServer::Servant preinvoke (const PortableServer::ObjectId &oid,
PortableServer::POA_ptr adapter,
const char *operation,
PortableServer::ServantLocator::Cookie &the_cookie,
CORBA::Environment &env);
// This method is invoked by a POA whenever it receives a request
// for MyFoo object that is not currently active. When the POA is
// created using the NON_RETAIN policy the Active Object Map is not
// maintained, in other words, an association between the ObjectId
// and the servant is not maintained. Hence every client request the
// servant has to be loaded. Note the operation argument. This
// argument specifies the operation to be invoked on the
// servant. The cookie helps in marking the servant. This marking is
// useful while destroying the servant.
virtual void postinvoke (const PortableServer::ObjectId &oid,
PortableServer::POA_ptr adapter,
const char *operation,
PortableServer::ServantLocator::Cookie the_cookie,
PortableServer::Servant the_servant,
CORBA::Environment &env);
// This method is invoked whenever a MyFooServant completes a
// request. As the Servant Loactor interface is used when the POA
// doesnt maintain the Active Object Map, its necessary to get rid
// of the servant after the client request has been processed. The
// appropriate servant is destroyed by verifying the cookie.Again
// this method is invoked per client request.
private:
ACE_CString dllname_;
// The name of the dll containing the servant.
ACE_CString create_symbol_;
// The symbol which on getting invoked will give us the servant
// pointer.
ACE_DLL dll_;
// The ACE_DLL object which performs the task of loading the dll
// and accessing it.
SERVANT_FACTORY servant_supplier_;
// The function pointer of factory_function type.
SERVANT_GARBAGE_COLLECTOR servant_garbage_collector_;
// The function pointer of garbage_collection_function type.
CORBA::ORB_var orb_;
// A reference to the ORB.
};
#endif /* SERVANT_LOCATOR_H */
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