TAO/tao/Wait_Strategy.h

   1 // -*- C++ -*-
   2
   3 //=============================================================================
   4 /**
   5  *  @file    Wait_Strategy.h
   6  *
   7  *  @author  Alexander Babu Arulanthu <alex@cs.wustl.edu>
   8  */
   9 //=============================================================================
  10
  11 #ifndef TAO_WAIT_STRATEGY_H
  12 #define TAO_WAIT_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 #include /**/ "tao/TAO_Export.h"
  23 #include /**/ "tao/Message_Semantics.h"
  24
  25 ACE_BEGIN_VERSIONED_NAMESPACE_DECL
  26 class ACE_Time_Value;
  27 class ACE_Event_Handler;
  28 ACE_END_VERSIONED_NAMESPACE_DECL
  29
  30 TAO_BEGIN_VERSIONED_NAMESPACE_DECL
  31
  32 class TAO_ORB_Core;
  33 class TAO_Transport;
  34 class TAO_Synch_Reply_Dispatcher;
  35
  36 /**
  37  * @class TAO_Wait_Strategy
  38  *
  39  * @brief Strategy for waiting for the reply.
  40  */
  41 class TAO_Export TAO_Wait_Strategy
  42 {
  43 public:
  44   /// Constructor.
  45   explicit TAO_Wait_Strategy (TAO_Transport *transport);
  46
  47   /// Destructor.
  48   virtual ~TAO_Wait_Strategy () = default;
  49
  50   /**
  51    * The user is going to send a request, prepare any internal
  52    * variables because the reply may arrive *before* the user calls
  53    * wait.
  54    */
  55   virtual int sending_request (TAO_ORB_Core *orb_core, TAO_Message_Semantics msg_semantics);
  56
  57   // The ORB finished handling the request; either the reply was received
  58   // and dispatched, the request timed out or the connection was closed.
  59   virtual void finished_request ();
  60
  61   /// Base class virtual method. Wait till the @c reply_received flag is
  62   /// true or the time expires.
  63   virtual int wait (ACE_Time_Value *max_wait_time,
  64                     TAO_Synch_Reply_Dispatcher &rd) = 0;
  65
  66   /// Register the handler needs with the reactor provided that it makes
  67   /// sense for the strategy.
  68   virtual int register_handler () = 0;
  69
  70   /// Returns a value to indicate whether the transport needs to set
  71   /// the socket on which it is waiting to non-blocking mode or not.
  72   virtual bool non_blocking () const = 0;
  73
  74   /// Flag that indicates whether we can process requests while
  75   /// waiting for the reply.
  76   /**
  77    * This flag is to check whether the thread can process upcalls
  78    * while waiting for the reply. Some wait strategies, like
  79    * Wait_On_LF_No_Upcall does not allow the client threads to process
  80    * requests while waiting for the reply.
  81    */
  82   virtual bool can_process_upcalls () const = 0;
  83
  84   /// Method to support deffering an upcall event till later in
  85   /// cases where can_process_upcalls() returns false.
  86   /// Some wait strategies like Wait_On_LF_No_Upcall allow an
  87   /// event to be deferred at the Leader_Follower which resumes
  88   /// the upcall at an opportune moment (when a new leader thread
  89   /// is activated).
  90   virtual int defer_upcall (ACE_Event_Handler*);
  91
  92   /// Get method for the flag
  93   bool is_registered () const;
  94
  95   /// Set method for the flag
  96   void is_registered (bool flag);
  97
  98 protected:
  99   /// Transport object.
 100   TAO_Transport *transport_;
 101
 102   /// Flag to indicate whether the service handler that created the
 103   /// above transport has been registered with the reactor or not. The
 104   /// default is false.
 105   bool is_registered_;
 106 };
 107
 108 TAO_END_VERSIONED_NAMESPACE_DECL
 109
 110
 111 #if defined (__ACE_INLINE__)
 112 # include "tao/Wait_Strategy.inl"
 113 #endif /* __ACE_INLINE__ */
 114
 115 #include /**/ "ace/post.h"
 116
 117 #endif /* TAO_WAIT_STRATEGY_H */