TAO/tao/Transport_Queueing_Strategies.h

   1 // -*- C++ -*-
   2
   3 //=============================================================================
   4 /**
   5  *  @file    Transport_Queueing_Strategies.h
   6  *
   7  *  Queueing strategies for the ORB Messaging layer.
   8  *
   9  *  @author  Irfan Pyarali
  10  */
  11 //=============================================================================
  12
  13
  14 #ifndef TAO_TRANSPORT_QUEUEING_STRATEGIES_H
  15 #define TAO_TRANSPORT_QUEUEING_STRATEGIES_H
  16
  17 #include /**/ "ace/pre.h"
  18
  19 #include /**/ "tao/TAO_Export.h"
  20
  21 #if !defined (ACE_LACKS_PRAGMA_ONCE)
  22 # pragma once
  23 #endif /* ACE_LACKS_PRAGMA_ONCE */
  24
  25 #include "tao/orbconf.h"
  26 #include "tao/Basic_Types.h"
  27
  28 ACE_BEGIN_VERSIONED_NAMESPACE_DECL
  29 class ACE_Time_Value;
  30 ACE_END_VERSIONED_NAMESPACE_DECL
  31
  32 TAO_BEGIN_VERSIONED_NAMESPACE_DECL
  33
  34 class TAO_Stub;
  35
  36 namespace TAO
  37 {
  38   /// Define the interface for the Queueing Strategy
  39   /**
  40    * The low-level I/O components in the ORB use this strategy to
  41    * determine when messages must be queued, immediately sent or
  42    * flushed.
  43    *
  44    * The strategy isolates this low-level components from the higher
  45    * level strategies used by the application developer.
  46    */
  47   class TAO_Export Transport_Queueing_Strategy
  48   {
  49   public:
  50     /// Destructor
  51     virtual ~Transport_Queueing_Strategy ();
  52
  53     /// Return true if a message must be queued
  54     virtual bool must_queue (bool queue_empty) const = 0;
  55
  56     /// Return true if it is time to start
  57     /**
  58      * @param stub The object used to make the request, this is used to
  59      *        obtain the policies currently in effect for the request
  60      * @param msg_count The number of messages currently queued
  61      * @param total_bytes Number of bytes currently queued
  62      * @param set_timer Returns true if a timer should be set to drain the
  63      *        queue
  64      * @param interval If set_timer returns 1, this parameter contains
  65      *        the timer interval
  66      * @param must_flush Is set to true if things must be flushed at this
  67      *        moment
  68      */
  69     virtual bool buffering_constraints_reached (
  70       TAO_Stub *stub,
  71       size_t msg_count,
  72       size_t total_bytes,
  73       bool &must_flush,
  74       const ACE_Time_Value &current_deadline,
  75       bool &set_timer,
  76       ACE_Time_Value &interval) const = 0;
  77   };
  78
  79   /**
  80    * This strategy doesn't not queue by default, but when a message is queued
  81    * we always flush it to the transport. This is used for oneways with
  82    * SYNC_WITH_TRANSPORT, SYNC_WITH_SERVER and SYNC_WITH_TARGET
  83    */
  84   class Flush_Transport_Queueing_Strategy : public Transport_Queueing_Strategy
  85   {
  86   public:
  87     virtual bool must_queue (bool queue_empty) const;
  88
  89     virtual bool buffering_constraints_reached (
  90       TAO_Stub *stub,
  91       size_t msg_count,
  92       size_t total_bytes,
  93       bool &must_flush,
  94       const ACE_Time_Value &current_deadline,
  95       bool &set_timer,
  96       ACE_Time_Value &interval) const;
  97   };
  98 }
  99
 100 TAO_END_VERSIONED_NAMESPACE_DECL
 101
 102 #include /**/ "ace/post.h"
 103
 104 #endif /* TAO_TRANSPORT_QUEUEING_STRATEGY_H */