TAO/tao/CSD_ThreadPool/CSD_TP_Dispatchable_Visitor.h

   1 // -*- C++ -*-
   2
   3 //=============================================================================
   4 /**
   5  *  @file    CSD_TP_Dispatchable_Visitor.h
   6  *
   7  *  @author  Tim Bradley <bradley_t@ociweb.com>
   8  */
   9 //=============================================================================
  10
  11 #ifndef TAO_CSD_TP_DISPATCHABLE_VISITOR_H
  12 #define TAO_CSD_TP_DISPATCHABLE_VISITOR_H
  13
  14 #include /**/ "ace/pre.h"
  15
  16 #include "tao/CSD_ThreadPool/CSD_TP_Export.h"
  17
  18 #if !defined (ACE_LACKS_PRAGMA_ONCE)
  19 # pragma once
  20 #endif /* ACE_LACKS_PRAGMA_ONCE */
  21
  22 #include "tao/CSD_ThreadPool/CSD_TP_Queue_Visitor.h"
  23 #include "tao/CSD_ThreadPool/CSD_TP_Request.h"
  24
  25 TAO_BEGIN_VERSIONED_NAMESPACE_DECL
  26
  27 namespace TAO
  28 {
  29   namespace CSD
  30   {
  31     /**
  32      * @class TP_Dispatchable_Visitor
  33      *
  34      * @brief Used to extract the first "dispatchable" request from the queue.
  35      *
  36      * An instance of this visitor class is used by one of the worker
  37      * threads to locate the first "dispatchable" request in the queue.  If
  38      * such a request is visited, then this visitor will save a "copy" of
  39      * the request, indicate that the request should be removed from the
  40      * queue, and indicate that visitation should stop.
  41      *
  42      * An method is provided to retrieve a "copy" of the "dispatchable"
  43      * request that was saved off during visitation.  A nil reference
  44      * (ie, a NULL pointer) will be returned if no dispatchable request
  45      * was found.
  46      *
  47      */
  48     class TAO_CSD_TP_Export TP_Dispatchable_Visitor : public TP_Queue_Visitor
  49     {
  50     public:
  51       /// Default Constructor.
  52       TP_Dispatchable_Visitor();
  53
  54       /// Virtual Destructor.
  55       virtual ~TP_Dispatchable_Visitor();
  56
  57       /// Reset this visitor object in order to re-use it for another
  58       /// visitation of the request queue.  This sets the visitor's "result"
  59       /// (the TP_Request* data member) to its default value (a nil handle).
  60       void reset();
  61
  62       /// Returns true to continue visitation.  Returns false to stop
  63       /// visitation.  Sets the remove_flag to true if the request should
  64       /// be removed from the queue as a result of the visit.  Leaves the
  65       /// remove_flag alone otherwise.
  66       virtual bool visit_request(TP_Request* request, bool& remove_flag);
  67
  68       /// This returns a "copy" of the located request, or 0 if no request
  69       /// was located.
  70       TP_Request* request();
  71
  72
  73     private:
  74       /// A handle to the located request.
  75       TP_Request_Handle request_;
  76     };
  77   }
  78 }
  79
  80 TAO_END_VERSIONED_NAMESPACE_DECL
  81
  82 #if defined (__ACE_INLINE__)
  83 # include "tao/CSD_ThreadPool/CSD_TP_Dispatchable_Visitor.inl"
  84 #endif /* __ACE_INLINE__ */
  85
  86 #include /**/ "ace/post.h"
  87
  88 #endif /* TAO_CSD_TP_DISPATCHABLE_VISITOR_H */