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// -*- C++ -*-
//=============================================================================
/**
* @file Future_Set.h
*
* @author John Tucker <jtucker@infoglide.com>
*/
//=============================================================================
#ifndef ACE_FUTURE_SET_H
#define ACE_FUTURE_SET_H
#include /**/ "ace/pre.h"
#include "ace/Thread.h"
#include "ace/Message_Queue.h"
#include "ace/Future.h"
#include "ace/Hash_Map_Manager_T.h"
#include "ace/Null_Mutex.h"
#if !defined (ACE_LACKS_PRAGMA_ONCE)
#pragma once
#endif /* ACE_LACKS_PRAGMA_ONCE */
#if defined (ACE_HAS_THREADS)
ACE_BEGIN_VERSIONED_NAMESPACE_DECL
/**
* @class ACE_Future_Set
*
* @brief This class implements a mechanism that allows the values of
* a collection of ACE_Future objects to be accessed by reader threads
* as they become available. The caller(s) provide the ACE_Future_Set
* (i.e. the observer...) with the collection of ACE_Future objects
* (i.e. the subjects...) that are to be observed using the the
* ACE_Future_Set::insert() method. The caller(s) may then iterate
* over the collection in the order in which they become readable
* using the ACE_Future_Set::next_readable() method.
*/
template <class T>
class ACE_Future_Set : public ACE_Future_Observer<T>,
private ACE_Copy_Disabled
{
public:
/// Constructor.
ACE_Future_Set (ACE_Message_Queue<ACE_SYNCH> *future_notification_queue_ = 0);
/// Destructor.
~ACE_Future_Set ();
/**
* Return 1 if their are no ACE_Future objects left on its queue and
* 0 otherwise.
*
* When an ACE_Future_Set has no ACE_Future>subjects to observe it is
* empty. The ACE_Future_Set is in the empty state when either the caller(s)
* have retrieved every readable ACE_Future subject assigned the
* ACE_Future_Set via the ACE_Future_Set::next_readable() method,
* or when the ACE_Future_Set has not been assigned any subjects.
*/
int is_empty () const;
/**
* Enqueus the given ACE_Future into this objects queue when it is
* readable.
*
* Returns 0 if the future is successfully inserted, 1 if the
* future is already inserted, and -1 if failures occur.
*/
int insert (ACE_Future<T> &future);
/**
* Wait up to @a tv time to get the @a value. Note that @a tv must be
* specified in absolute time rather than relative time.); get the
* next ACE_Future that is readable. If @a tv = 0, the will block
* forever.
*
* If a readable future becomes available, then the input
* ACE_Future object param will be assigned with it and 1 will
* be returned. If the ACE_Future_Set is empty (i.e. see definition
* of ACE_Future_Set::is_empty()), then 0 is returned.
*
* When a readable ACE_Future object is retrieved via the
* ACE_Future_Set::next_readable() method, the ACE_Future_Set will
* remove that ACE_Future object from its list of subjects.
*/
int next_readable (ACE_Future<T> &result,
ACE_Time_Value *tv = 0);
/// Called by the ACE_Future subject in which we are subscribed to
/// when its value is written to.
virtual void update (const ACE_Future<T> &future);
/// Declare the dynamic allocation hooks.
ACE_ALLOC_HOOK_DECLARE;
private:
typedef ACE_Future<T> FUTURE;
typedef ACE_Future_Rep<T> FUTURE_REP;
typedef ACE_Future_Holder<T> FUTURE_HOLDER;
typedef ACE_Pointer_Hash<FUTURE_REP *> FUTURE_REP_HASH;
typedef ACE_Equal_To<FUTURE_REP *> FUTURE_REP_COMPARE;
typedef ACE_Hash_Map_Manager_Ex<FUTURE_REP *,
FUTURE_HOLDER *,
FUTURE_REP_HASH,
FUTURE_REP_COMPARE,
ACE_Null_Mutex> FUTURE_HASH_MAP;
/// Map of <ACE_Futures>, subjects, which have not been written to by
/// client's writer thread.
FUTURE_HASH_MAP future_map_;
/// Message queue for notifying the reader thread of <ACE_Futures> which
/// have been written to by client's writer thread.
ACE_Message_Queue<ACE_SYNCH> *future_notification_queue_;
/// Keeps track of whether we need to delete the message queue.
bool delete_queue_;
};
ACE_END_VERSIONED_NAMESPACE_DECL
#if defined (ACE_TEMPLATES_REQUIRE_SOURCE)
#include "ace/Future_Set.cpp"
#endif /* ACE_TEMPLATES_REQUIRE_SOURCE */
#if defined (ACE_TEMPLATES_REQUIRE_PRAGMA)
#pragma implementation ("Future_Set.cpp")
#endif /* ACE_TEMPLATES_REQUIRE_PRAGMA */
#endif /* ACE_HAS_THREADS */
#include /**/ "ace/post.h"
#endif /* ACE_FUTURE_SET_H */
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