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// This may look like C, but it's really -*- C++ -*-
//=============================================================================
/**
* @file Servant_Locator.h
*
* Defines a ServantLocator class , used with a POA having
* a NON_RETAIN policy.
*
* @author Kirthika Parameswaran <kirthika@cs.wustl.edu>
*/
//=============================================================================
#ifndef SERVANT_LOCATOR_H
#define SERVANT_LOCATOR_H
#include "tao/PortableServer/PortableServer.h"
#include "tao/PortableServer/ServantLocatorC.h"
#include "tao/LocalObject.h"
#include "tao/ORB.h"
#include "ace/DLL.h"
#include "ace/SString.h"
#include "ace/Log_Msg.h"
class ServantLocator :
public virtual PortableServer::ServantLocator,
public virtual ::CORBA::LocalObject
{
// = 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:
/**
* 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 PortableServer::Servant
(*SERVANT_FACTORY) (const PortableServer::ObjectId &oid,
PortableServer::POA_ptr poa,
CORBA::ORB_ptr orb);
/**
* This typedef is used to obtain the garbage_collection_function symbol
* in the dll. Invoking the function pointer obtained would then destroy
* the servant.
*/
typedef void
(*SERVANT_GARBAGE_COLLECTOR) (const PortableServer::ObjectId &oid,
PortableServer::POA_ptr,
PortableServer::Servant servant);
/// Constructor.
ServantLocator (CORBA::ORB_ptr orb,
const ACE_TCHAR *dllname,
const ACE_TCHAR *factory_function,
const ACE_TCHAR *garbage_collection_function);
/**
* This method is invoked by a POA whenever it receives a request
* for test 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 PortableServer::Servant preinvoke (const PortableServer::ObjectId &oid,
PortableServer::POA_ptr adapter,
const char *operation,
PortableServer::ServantLocator::Cookie &the_cookie);
/**
* This method is invoked whenever a test servant 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.
*/
virtual void postinvoke (const PortableServer::ObjectId &oid,
PortableServer::POA_ptr adapter,
const char *operation,
PortableServer::ServantLocator::Cookie the_cookie,
PortableServer::Servant the_servant);
private:
/// The name of the dll containing the servant.
ACE_CString dllname_;
/// The symbol which on getting invoked will give us the servant
/// pointer.
ACE_CString create_symbol_;
/// The ACE_DLL object which performs the task of loading the dll
/// and accessing it.
ACE_DLL dll_;
/// The function pointer of factory_function type.
SERVANT_FACTORY servant_supplier_;
/// The function pointer of garbage_collection_function type.
SERVANT_GARBAGE_COLLECTOR servant_garbage_collector_;
/// A reference to the ORB.
CORBA::ORB_var orb_;
};
#endif /* SERVANT_LOCATOR_H */
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