peer_router.h

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/* -*- C++ -*- */
// $Id: Peer_Router.h 51476 2003-08-04 03:53:54Z dhinton $

#ifndef _PEER_ROUTER_H
#define _PEER_ROUTER_H

#include "ace/Acceptor.h"

#if !defined (ACE_LACKS_PRAGMA_ONCE)
# pragma once
#endif /* ACE_LACKS_PRAGMA_ONCE */

#include "ace/SOCK_Acceptor.h"
#include "ace/Svc_Handler.h"
#include "ace/Map_Manager.h"
#include "ace/RW_Thread_Mutex.h"

// Type of search key for CONSUMER_MAP
typedef ACE_HANDLE ROUTING_KEY;

// Forward declarations.
class Peer_Router;
class Peer_Router_Context;

class Peer_Handler : public ACE_Svc_Handler<ACE_SOCK_STREAM, ACE_SYNCH>
{
  // = TITLE
  //     Receive input from a Peer and forward to the appropriate
  //     <Peer_Router> (i.e., <Consumer_Router> or <Supplier_Router>).
public:
  Peer_Handler (Peer_Router_Context * = 0);
  // Initialization method.

  virtual int open (void * = 0);
  // Called by the ACE_Acceptor::handle_input() to activate this
  // object.

  virtual int handle_input (ACE_HANDLE);
  // Receive input from a peer.

  virtual int put (ACE_Message_Block *, ACE_Time_Value *tv = 0);
  // Send output to a peer.  Note that this implementation "blocks" if
  // flow control occurs.  This is undesirable for "real"
  // applications.  The best way around this is to make the
  // <Peer_Handler> an Active Object, e.g., as done in the
  // $ACE_ROOT/apps/Gateway/Gateway application.

protected:
  Peer_Router_Context *peer_router_context_;
  // Pointer to router context.  This maintains the state that is
  // shared by both Tasks in a <Peer_Router> Module.
};

class Peer_Router_Context : public ACE_Acceptor<Peer_Handler, ACE_SOCK_ACCEPTOR>
{
  // = TITLE
  //     Defines state and behavior shared between both Tasks in a
  //     <Peer_Router> Module.
  //
  // = DESCRIPTION
  //     This class also serves as an <ACE_Acceptor>, which creates
  //     <Peer_Handlers> when Peers connect.
public:
  // = Initialization and termination methods.
  Peer_Router_Context (u_short port);
  // Constructor.

  virtual int unbind_peer (ROUTING_KEY);
  // Remove the <Peer_Handler *> from the <PEER_MAP> that corresponds
  // to the <ROUTING_KEY>.

  virtual int bind_peer (ROUTING_KEY, Peer_Handler *);
  // Add a <Peer_Handler> to the <PEER_MAP> that's associated with the
  // <ROUTING_KEY>.

  int send_peers (ACE_Message_Block *mb);
  // Send the <ACE_Message_Block> to all the peers.  Note that in a
  // "real" application this logic would most likely be more
  // selective, i.e., it would actually do "routing" based on
  // addressing information passed in the <ACE_Message_Block>.

  int make_svc_handler (Peer_Handler *&sh);
  // Factory Method that creates a new <Peer_Handler> for each
  // connection.  This method overrides the default behavior in
  // <ACE_Acceptor>.

  // = Set/Get Router Task.
  Peer_Router *peer_router (void);
  void peer_router (Peer_Router *);

  void release (void);
  // Decrement the reference count and delete <this> when count == 0;

  void duplicate (void);
  // Increment the reference count.

private:
  Peer_Router *peer_router_;
  // Pointer to the <Peer_Router> that we are accepting for.

  // = Useful typedefs.
  typedef ACE_Map_Manager <ROUTING_KEY, Peer_Handler *, ACE_SYNCH_RW_MUTEX>
          PEER_MAP;
  typedef ACE_Map_Iterator<ROUTING_KEY, Peer_Handler *, ACE_SYNCH_RW_MUTEX>
          PEER_ITERATOR;
  typedef ACE_Map_Entry<ROUTING_KEY, Peer_Handler *>
          PEER_ENTRY;

  PEER_MAP peer_map_;
  // Map used to keep track of active peers.

  int reference_count_;
  // Keep track of when we can delete ourselves.

  ~Peer_Router_Context (void);
  // Private to ensure dynamic allocation.

  friend class Friend_Of_Peer_Router_Context;
  // Declare a friend class to avoid compiler warnings because the
  // destructor is private.
};

class Peer_Router : public ACE_Task<ACE_SYNCH>
{
  // = TITLE
  //     This abstract base class provides mechanisms for routing
  //     messages to/from a <ACE_Stream> from/to one or more peers (which
  //     are typically running on remote hosts).
  //
  // = DESCRIPTION
  //     Subclasses of <Peer_Router> (such as <Consumer_Router> or
  //     <Supplier_Router>) override the <open>, <close>, and
  //     <put> methods to specialize the behavior of the router to
  //     meet application-specific requirements.
protected:
  Peer_Router (Peer_Router_Context *prc);
  // Initialization method.

  virtual int control (ACE_Message_Block *);
  // Handle control messages arriving from adjacent Modules.

  Peer_Router_Context *context (void) const;
  // Returns the routing context.

  typedef ACE_Task<ACE_SYNCH> inherited;
  // Helpful typedef.

private:
  Peer_Router_Context *peer_router_context_;
  // Reference to the context shared by the writer and reader Tasks,
  // e.g., in the <Consumer_Router> and <Supplier_Router> Modules.

  // = Prevent copies and pass-by-value.
  Peer_Router (const Peer_Router &);
  void operator= (const Peer_Router &);
};

#endif /* _PEER_ROUTER_H */