dep/ACE_wrappers/ace/Method_Request.h

   1 // -*- C++ -*-
   2
   3 //=============================================================================
   4 /**
   5  *  @file    Method_Request.h
   6  *
   7  *  $Id: Method_Request.h 80826 2008-03-04 14:51:23Z wotte $
   8  *
   9  *  @author Andres Kruse <Andres.Kruse@cern.ch>
  10  *  @author Douglas C. Schmidt <schmidt@cs.wustl.edu>
  11  */
  12 //=============================================================================
  13
  14
  15 #ifndef ACE_METHOD_REQUEST_H
  16 #define ACE_METHOD_REQUEST_H
  17
  18 #include /**/ "ace/pre.h"
  19
  20 #include /**/ "ace/ACE_export.h"
  21
  22 #if !defined (ACE_LACKS_PRAGMA_ONCE)
  23 # pragma once
  24 #endif /* ACE_LACKS_PRAGMA_ONCE */
  25
  26 #include "ace/Global_Macros.h"
  27
  28 ACE_BEGIN_VERSIONED_NAMESPACE_DECL
  29
  30 /**
  31  * @class ACE_Method_Request
  32  *
  33  * @brief Reifies a method into a request.  Subclasses must provide
  34  * the necessary state and behavior.
  35  *
  36  * An ACE_Method_Request is inserted in an ACE_Activation_Queue,
  37  * where it is subsequently removed by a scheduler object (often
  38  * derived from ACE_Task), which invokes the @c call() method.
  39  *
  40  * This class is discussed in depth in the Active Object chapter
  41  * of POSA2.
  42  *
  43  * @sa ACE_Activation_Queue
  44  */
  45 class ACE_Export ACE_Method_Request
  46 {
  47 public:
  48   // = Initialization and termination methods.
  49   /// Constructor.
  50   ACE_Method_Request (unsigned long priority = 0);
  51
  52   /// Destructor.
  53   virtual ~ACE_Method_Request (void);
  54
  55   // = Accessors.
  56   /// Get priority.
  57   unsigned long priority (void) const;
  58
  59   /// Set priority.
  60   /**
  61    * Priority values are user-defined. The default (set in the constructor)
  62    * is 0. The priority value is used in the ACE_Activation_Queue::enqueue()
  63    * method to order the method requests in the queue by priority.
  64    * 0 is the lowest priority.
  65    *
  66    * @param prio   unsigned long, the new priority value for this object.
  67    *
  68    * @sa ACE_Activation_Queue::enqueue
  69    */
  70   void priority (unsigned long prio);
  71
  72   // = Invocation method (must be overridden by subclasses).
  73   /// Invoked by the scheduler to execute the request.
  74   /**
  75    * This method must be implemented by the subclass to perform the
  76    * desired actions.
  77    *
  78    * @return int; not interpreted by ACE. The scheduler class must
  79    *         decide the meaning of this return value and act on it
  80    *         if needed.
  81    */
  82   virtual int call (void) = 0;
  83
  84 private:
  85
  86   /// Disallow copying and assignment.
  87   ACE_Method_Request (const ACE_Method_Request &);
  88   void operator= (const ACE_Method_Request &);
  89
  90 protected:
  91   /// The priority of the request.
  92   unsigned long priority_;
  93
  94 };
  95
  96 ACE_END_VERSIONED_NAMESPACE_DECL
  97
  98
  99 #include /**/ "ace/post.h"
 100 #endif /* ACE_METHOD_REQUEST_H */