TAO/tao/LF_CH_Event.h

   1 // -*- C++ -*-
   2
   3 //=============================================================================
   4 /**
   5  *  @file LF_CH_Event.h
   6  *
   7  *  @author Balachandran Natarajan <bala@cs.wustl.edu>
   8  */
   9 //=============================================================================
  10
  11 #ifndef TAO_LF_CH_EVENT_H
  12 #define TAO_LF_CH_EVENT_H
  13
  14 #include /**/ "ace/pre.h"
  15
  16 #include "tao/LF_Event.h"
  17 #include "tao/orbconf.h"
  18 #include "ace/Hash_Map_Manager_T.h"
  19 #include "ace/Null_Mutex.h"
  20 #include "ace/Thread_Mutex.h"
  21
  22 #if !defined (ACE_LACKS_PRAGMA_ONCE)
  23 # pragma once
  24 #endif /* ACE_LACKS_PRAGMA_ONCE */
  25
  26 TAO_BEGIN_VERSIONED_NAMESPACE_DECL
  27
  28 class TAO_LF_Multi_Event;
  29
  30 /**
  31  * @class TAO_LF_CH_Event
  32  *
  33  * @brief Use the Leader/Follower loop to wait for one specific event
  34  * in the invocation path.
  35  *
  36  * Concrete event types and manipulation class which is used for
  37  * connection handling purposes.
  38  */
  39 class TAO_Export TAO_LF_CH_Event: public TAO_LF_Event
  40 {
  41 public:
  42   /**
  43    * The TAO_LF_Multi_Event class is another specialization of
  44    * TAO_LF_Event, used for aggregating many connection handlers into
  45    * a single event object. It requires friendship so that it can
  46    * check the is_state_final() flag on each of its contained
  47    * connection handlers.
  48    */
  49   friend class TAO_LF_Multi_Event;
  50
  51   /// Constructor
  52   TAO_LF_CH_Event ();
  53
  54   /// Destructor
  55   virtual ~TAO_LF_CH_Event ();
  56
  57   //@{
  58 protected:
  59   /// Check whether we have reached the final state..
  60   virtual bool is_state_final () const;
  61
  62   //@}
  63 private:
  64   /// Validate and change the state
  65   /*
  66    * This concrete class uses the following states declared in the
  67    * class TAO_LF_Event to transition states
  68    *
  69    * LFS_IDLE                  - The event is created, and is in
  70    *                             initial  state.
  71    *
  72    * LFS_CONNECTION_WAIT       - The event is waiting for connection
  73    *                             completion and it can transition to
  74    *                             any of the following states, all the
  75    *                             states are final.
  76    *
  77    * LFS_SUCCESS               - The event, connection establishment, has
  78    *                             completed successfully.
  79    *
  80    * LFS_TIMEOUT               - The event has timed out.
  81    *
  82    * LFS_CONNECTION_CLOSED     - The connection was closed since
  83    *                             an error occurred while trying to
  84    *                             establish connection
  85    *
  86    *  Event State Diagram
  87    *  -------------------
  88    *                              |----> CLOSED
  89    *                              |        ^
  90    *                              |        |
  91    *   IDLE ---> CONNECTION_WAIT--|        |
  92    *                              |        |
  93    *                              |        |
  94    *                              |----> SUCESS
  95    *
  96    * Timeouts can occur while waiting for connections.
  97    *
  98    */
  99   virtual void state_changed_i (LFS_STATE new_state);
 100
 101   /// Return true if the condition was satisfied successfully, false if it
 102   /// has not
 103   virtual bool successful_i () const;
 104
 105   /// Return true if an error was detected while waiting for the
 106   /// event
 107   virtual bool error_detected_i () const;
 108
 109   /// Set the state irrespective of anything.
 110   virtual void set_state (LFS_STATE new_state);
 111
 112   virtual int bind (TAO_LF_Follower *follower);
 113   virtual int unbind (TAO_LF_Follower *follower);
 114
 115 private:
 116   /// The previous state that the LF_CH_Event was in
 117   LFS_STATE prev_state_;
 118
 119   void validate_state_change (LFS_STATE new_state);
 120
 121   typedef ACE_Hash_Map_Manager_Ex <TAO_LF_Follower *, int,
 122                                    ACE_Hash<void *>,
 123                                    ACE_Equal_To<TAO_LF_Follower *>,
 124                                    TAO_SYNCH_MUTEX>                  HASH_MAP;
 125   HASH_MAP followers_;
 126 };
 127
 128 TAO_END_VERSIONED_NAMESPACE_DECL
 129
 130 #include /**/ "ace/post.h"
 131
 132 #endif  /* TAO_LF_CH_EVENT_H */