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// -*- C++ -*-
//=============================================================================
/**
* @file Pluggable_Messaging.h
*
* $Id$
*
* Interface for the TAO pluggable messaging framework.
*
*
* @author Balachandran Natarajan <bala@cs.wustl.edu>
*/
//=============================================================================
//
#ifndef TAO_PLUGGABLE_MESSAGING_H
#define TAO_PLUGGABLE_MESSAGING_H
#include "ace/pre.h"
#include "tao/Pluggable_Messaging_Utils.h"
#include "tao/Exception.h"
#if !defined (ACE_LACKS_PRAGMA_ONCE)
# pragma once
#endif /* ACE_LACKS_PRAGMA_ONCE */
class TAO_Target_Specification;
class TAO_Pluggable_Reply_Params;
class TAO_Transport;
class TAO_Operation_Details;
class TAO_Target_Specification;
class TAO_OutputCDR;
// @@ The more I think I about this class, I feel that this class need
// not be a ABC as it is now. Instead we have these options
// (1) Parametrize this class with the "Messaging Object". Then the
// implementations can just redirect the request to the class
// that it has been specialised with
// (2) Use a bridge pattern here ie. the interface exposed by this
// class will redirect the request to the implementation which
// would be "right messaging" object.
// Both of them feasible. If we are not going like templates much, (2)
// is seems to be a better option.
// I am going to take a closer look on this after my MS defense -
// Bala
/**
* @class TAO_Pluggable_Messaging
*
* @brief Generic definitions Messaging class.
*
* This interface tries to define generic methods that could be
* different messaging protocols
*/
class TAO_Export TAO_Pluggable_Messaging
{
public:
/// Dtor
virtual ~TAO_Pluggable_Messaging (void);
/// Write the RequestHeader in to the <cdr> stream. The underlying
/// implementation of the mesaging should do the right thing.
virtual int generate_request_header (
TAO_Operation_Details &op,
TAO_Target_Specification &spec,
TAO_OutputCDR &cdr) = 0;
/// Write the RequestHeader in to the <cdr> stream.
virtual int generate_locate_request_header (
TAO_Operation_Details &op,
TAO_Target_Specification &spec,
TAO_OutputCDR &cdr) = 0;
/**
* Write the reply header
* The reply header is a part of any messaging protocol. The
* messaging protocol implementation would implement the way the
* reply header is written.
*/
virtual int generate_reply_header (
TAO_OutputCDR &cdr,
TAO_Pluggable_Reply_Params_Base ¶ms) = 0;
/**
* Write the locate reply header
* The locate reply header is a part of any messaging protocol. The
* messaging protocol implementation would implement the way the
* locate reply header is written.
*/
virtual int generate_locate_reply_header (
TAO_OutputCDR &cdr,
TAO_Pluggable_Reply_Params_Base ¶ms) = 0;
/**
* This method reads the message on the connection. Returns 0 when
* there is short read on the connection. Returns 1 when the full
* message is read and handled. Returns -1 on errors. If <block> is
* 1, then reply is read in a blocking manner. <bytes> indicates the
* number of bytes that needs to be read from the connection.
*/
virtual int read_message (TAO_Transport *transport,
int block = 0,
ACE_Time_Value *max_wait_time = 0) = 0;
/// Format the message in the <cdr>. May not be needed in
/// general.
virtual int format_message (TAO_OutputCDR &cdr) = 0;
/// Get the message type that was received.
virtual TAO_Pluggable_Message_Type message_type (void) = 0;
/// Do any initialisations that may be needed.
virtual void init (CORBA::Octet major,
CORBA::Octet minor) = 0;
/// Reset teh messaging object
virtual void reset (int reset_flag = 1) = 0;
// Reset the messaging object
/// Parse the request message, make an upcall and send the reply back
/// to the "request initiator"
virtual int process_request_message (TAO_Transport *transport,
TAO_ORB_Core *orb_core) = 0;
/// Parse the reply message that we received and return the reply
/// information though <reply_info>
virtual int process_reply_message (
TAO_Pluggable_Reply_Params &reply_info) = 0;
/// Generate a reply message with the exception <ex>.
virtual int generate_exception_reply (
TAO_OutputCDR &cdr,
TAO_Pluggable_Reply_Params_Base ¶ms,
CORBA::Exception &x) = 0;
/// Is the messaging object ready for processing BiDirectional
/// request/response?
virtual int is_ready_for_bidirectional (void) = 0;
/// Are there any more messages that needs processing?
virtual int more_messages (void);
};
#if defined (__ACE_INLINE__)
# include "tao/Pluggable_Messaging.i"
#endif /* __ACE_INLINE__ */
#include "ace/post.h"
#endif /*TAO_PLUGGABLE_MESSAGING_H*/
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