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Diffstat (limited to 'ACE/ace/Activation_Queue.h')
| -rw-r--r-- | ACE/ace/Activation_Queue.h | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/ACE/ace/Activation_Queue.h b/ACE/ace/Activation_Queue.h new file mode 100644 index 00000000000..a356b1f0a34 --- /dev/null +++ b/ACE/ace/Activation_Queue.h @@ -0,0 +1,168 @@ +// -*- C++ -*- + +//============================================================================= +/** + * @file Activation_Queue.h + * + * $Id$ + * + * @author Andres Kruse <Andres.Kruse@cern.ch> + * @author Douglas C. Schmidt <schmidt@cs.wustl.edu> + */ +//============================================================================= + +#ifndef ACE_ACTIVATION_QUEUE_H +#define ACE_ACTIVATION_QUEUE_H + +#include /**/ "ace/pre.h" + +#include /**/ "ace/ACE_export.h" + +#if !defined (ACE_LACKS_PRAGMA_ONCE) +# pragma once +#endif /* ACE_LACKS_PRAGMA_ONCE */ + +#include "ace/Message_Queue.h" +#include "ace/Copy_Disabled.h" +#include "ace/Condition_Thread_Mutex.h" + +/// Define to be compatible with the terminology in the POSA2 book! +#define ACE_Activation_List ACE_Activation_Queue + +ACE_BEGIN_VERSIONED_NAMESPACE_DECL + +class ACE_Method_Request; + +/** + * @class ACE_Activation_Queue + * + * @brief + * Reifies a method into a request. Subclasses typically + * represent necessary state and behavior. + * + * Maintains a priority-ordered queue of ACE_Method_Request objects. + * A scheduler class (often derived from ACE_Task) subsequently removes + * each method request and invokes its @c call() method. + * + * This class is discussed in depth in the Active Object chapter + * of POSA2. In that book, it is referred to as an Activation List. + * + * @sa ACE_Method_Request + */ +class ACE_Export ACE_Activation_Queue : private ACE_Copy_Disabled +{ +public: + /// Constructor. + /** + * Initializes a new activation queue. + * + * @param new_queue The activation queue uses an ACE_Message_Queue to + * queue and order the method requests. If this argument + * is 0, a new ACE_Message_Queue is created for this + * object's use and will be deleted when this object is + * destroyed. If a non-zero pointer is supplied, the + * passed object will be used and will not be deleted when + * this object is destroyed. If an ACE_Task is being created + * to act as the scheduler, for instance, its + * ACE_Message_Queue pointer can be passed to this object. + * @param alloc Optional, the allocator to use when allocating + * ACE_Message_Block instances that wrap the method requests + * queued to this activation queue. Defaults to + * ACE_Allocator::instance(). + * @param db_alloc Optional, the allocator to use when allocating + * data blocks for the ACE_Message_Block instances that + * wrap the method requests queued to this activation queue. + * Defaults to ACE_Allocator::instance(). + */ + ACE_Activation_Queue (ACE_Message_Queue<ACE_SYNCH> *new_queue = 0, + ACE_Allocator *alloc = 0, + ACE_Allocator *db_alloc = 0); + + /// Destructor. + virtual ~ACE_Activation_Queue (void); + + // = Activate Queue operations. + + /// Dequeue the next available ACE_Method_Request. + /** + * @param tv If 0, the method will block until a method request is + * available, else will wait until the absolute time specified + * in the referenced ACE_Time_Value. This method will return, + * earlier, however, if queue is closed, deactivated, or when + * a signal occurs. + * + * @retval Pointer to the dequeued ACE_Method_Request object. + * @retval 0 an error occurs; errno contains further information. If + * the specified timeout elapses, errno will be @c EWOULDBLOCK. + */ + ACE_Method_Request *dequeue (ACE_Time_Value *tv = 0); + + /// Enqueue the ACE_Method_Request in priority order. + /** + * The priority of the method request is obtained via the @c priority() + * method of the queued method request. Priority ordering is determined + * by the ACE_Message_Queue class; 0 is the lowest priority. + * + * @param new_method_request Pointer to the ACE_Method_Request object to + * queue. This object's @c priority() method is called to obtain + * the priority. + * @param tv If 0, the method will block until the method request can + * be queued, else will wait until the absolute time specified + * in the referenced ACE_Time_Value. This method will return, + * earlier, however, if queue is closed, deactivated, or when + * a signal occurs. + * + * @retval >0 The number of method requests on the queue after adding + * the specified request. + * @retval -1 if an error occurs; errno contains further information. If + * the specified timeout elapses, errno will be @c EWOULDBLOCK. + */ + int enqueue (ACE_Method_Request *new_method_request, ACE_Time_Value *tv = 0); + + /// Get the current number of method objects in the queue. + size_t method_count (void) const; + + /// Returns 1 if the queue is empty, 0 otherwise. + int is_empty (void) const; + + /// Returns 1 if the queue is full, 0 otherwise. + int is_full (void) const; + + /// Dump the state of an request. + void dump (void) const; + + /// Get a pointer to the underlying queue. + ACE_Message_Queue<ACE_SYNCH> *queue (void) const; + + /// Set the pointer to the underlying queue. + void queue (ACE_Message_Queue<ACE_SYNCH> *q); + + /// Declare the dynamic allocation hooks. + ACE_ALLOC_HOOK_DECLARE; + +protected: + + /// Stores the Method_Requests. + ACE_Message_Queue<ACE_SYNCH> *queue_; + + /// Keeps track of whether we need to delete the queue. + bool delete_queue_; + +private: + + /// Allocation strategy of the queue. + ACE_Allocator *allocator_; + + /// Allocation strategy of the message blocks. + ACE_Allocator *data_block_allocator_; + +}; + +ACE_END_VERSIONED_NAMESPACE_DECL + +#if defined (__ACE_INLINE__) +#include "ace/Activation_Queue.inl" +#endif /* __ACE_INLINE__ */ + +#include /**/ "ace/post.h" +#endif /* ACE_ACTIVATION_QUEUE_H */ |