TAO/tao/Flushing_Strategy.h

   1 // -*- C++ -*-
   2
   3 //=============================================================================
   4 /**
   5  *  @file Flushing_Strategy.h
   6  *
   7  *  @author Carlos O'Ryan <coryan@uci.edu>
   8  */
   9 //=============================================================================
  10
  11 #ifndef TAO_FLUSHING_STRATEGY_H
  12 #define TAO_FLUSHING_STRATEGY_H
  13
  14 #include /**/ "ace/pre.h"
  15
  16 #include "tao/orbconf.h"
  17
  18 #if !defined (ACE_LACKS_PRAGMA_ONCE)
  19 # pragma once
  20 #endif /* ACE_LACKS_PRAGMA_ONCE */
  21
  22 ACE_BEGIN_VERSIONED_NAMESPACE_DECL
  23 class ACE_Time_Value;
  24 ACE_END_VERSIONED_NAMESPACE_DECL
  25
  26 TAO_BEGIN_VERSIONED_NAMESPACE_DECL
  27
  28 class TAO_Transport;
  29 class TAO_Queued_Message;
  30
  31 /**
  32  * @class TAO_Flushing_Strategy
  33  *
  34  * @brief Define the interface for the flushing strategy, i.e. the
  35  *        algorithm that controls how does the ORB flush outgoing
  36  *        data.
  37  *
  38  * Please read the documentation in the TAO_Transport class to find
  39  * out more about the design of the outgoing data path.
  40  *
  41  * Some applications can block the current thread whenever they are
  42  * sending out data.  In those cases they can obtain better
  43  * performance by blocking in calls to write() than by participating
  44  * in the Leader/Followers protocol to shared the ORB Reactor.
  45  *
  46  * This strategy controls how does the ORB schedule and cancel
  47  * reactive I/O, if there is no reactive I/O the strategy is just a
  48  * no-op.
  49  */
  50 class TAO_Flushing_Strategy
  51 {
  52 public:
  53   /// Destructor
  54   virtual ~TAO_Flushing_Strategy (void);
  55
  56   enum SCHEDULE_OUTPUT_RETURN { MUST_FLUSH = -2 };
  57
  58   /// Schedule the transport argument to be flushed
  59   /// If -2 is returned then the caller must call one of
  60   ///   the flush_* methods.
  61   /// If -1 is returned then there was an error.
  62   /// If 0 is returned then the flush was scheduled successfully.
  63   virtual int schedule_output (TAO_Transport *transport) = 0;
  64
  65   /// Cancel all scheduled output for the transport argument
  66   virtual int cancel_output (TAO_Transport *transport) = 0;
  67
  68   /// Wait until @a msg is sent out.  Potentially other messages are
  69   /// flushed too, for example, because there are ahead in the queue.
  70   virtual int flush_message (TAO_Transport *transport,
  71                              TAO_Queued_Message *msg,
  72                              ACE_Time_Value *max_wait_time) = 0;
  73
  74   /// Wait until the transport has no messages queued.
  75   virtual int flush_transport (TAO_Transport *transport, ACE_Time_Value *max_wait_time) = 0;
  76 };
  77
  78 TAO_END_VERSIONED_NAMESPACE_DECL
  79
  80 #include /**/ "ace/post.h"
  81
  82 #endif  /* TAO_FLUSHING_STRATEGY_H */