ACE/ace/Method_Request.h

   1 // -*- C++ -*-
   2
   3 //=============================================================================
   4 /**
   5  *  @file    Method_Request.h
   6  *
   7  *  @author Andres Kruse <Andres.Kruse@cern.ch>
   8  *  @author Douglas C. Schmidt <d.schmidt@vanderbilt.edu>
   9  */
  10 //=============================================================================
  11
  12
  13 #ifndef ACE_METHOD_REQUEST_H
  14 #define ACE_METHOD_REQUEST_H
  15
  16 #include /**/ "ace/pre.h"
  17
  18 #include /**/ "ace/ACE_export.h"
  19
  20 #if !defined (ACE_LACKS_PRAGMA_ONCE)
  21 # pragma once
  22 #endif /* ACE_LACKS_PRAGMA_ONCE */
  23
  24 #include "ace/Global_Macros.h"
  25
  26 ACE_BEGIN_VERSIONED_NAMESPACE_DECL
  27
  28 /**
  29  * @class ACE_Method_Request
  30  *
  31  * @brief Reifies a method into a request.  Subclasses must provide
  32  * the necessary state and behavior.
  33  *
  34  * An ACE_Method_Request is inserted in an ACE_Activation_Queue,
  35  * where it is subsequently removed by a scheduler object (often
  36  * derived from ACE_Task), which invokes the @c call() method.
  37  *
  38  * This class is discussed in depth in the Active Object chapter
  39  * of POSA2.
  40  *
  41  * @sa ACE_Activation_Queue
  42  */
  43 class ACE_Export ACE_Method_Request
  44 {
  45 public:
  46   /// Constructor.
  47   ACE_Method_Request (unsigned long priority = 0);
  48
  49   /// Destructor.
  50   virtual ~ACE_Method_Request () = default;
  51
  52   // = Accessors.
  53   /// Get priority.
  54   unsigned long priority () const;
  55
  56   /// Set priority.
  57   /**
  58    * Priority values are user-defined. The default (set in the constructor)
  59    * is 0. The priority value is used in the ACE_Activation_Queue::enqueue()
  60    * method to order the method requests in the queue by priority.
  61    * 0 is the lowest priority.
  62    *
  63    * @param prio   unsigned long, the new priority value for this object.
  64    *
  65    * @sa ACE_Activation_Queue::enqueue
  66    */
  67   void priority (unsigned long prio);
  68
  69   // = Invocation method (must be overridden by subclasses).
  70   /// Invoked by the scheduler to execute the request.
  71   /**
  72    * This method must be implemented by the subclass to perform the
  73    * desired actions.
  74    *
  75    * @return int; not interpreted by ACE. The scheduler class must
  76    *         decide the meaning of this return value and act on it
  77    *         if needed.
  78    */
  79   virtual int call () = 0;
  80
  81 private:
  82   ACE_Method_Request (const ACE_Method_Request &) = delete;
  83   void operator= (const ACE_Method_Request &) = delete;
  84   ACE_Method_Request (ACE_Method_Request &&) = delete;
  85   void operator= (ACE_Method_Request &&) = delete;
  86
  87 protected:
  88   /// The priority of the request.
  89   unsigned long priority_;
  90 };
  91
  92 ACE_END_VERSIONED_NAMESPACE_DECL
  93
  94
  95 #include /**/ "ace/post.h"
  96 #endif /* ACE_METHOD_REQUEST_H */