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ACE_Future Class Template Reference

This class implements a ``single write, multiple read'' pattern that can be used to return results from asynchronous method invocations. More...

#include <Future.h>

Collaboration diagram for ACE_Future:

[legend]List of all members.

Public Methods
	ACE_Future (void)
	Constructor. More...
	ACE_Future (const ACE_Future< T > &r)
	Copy constructor binds this and r to the same ACE_Future_Rep. An ACE_Future_Rep is created if necessary. More...
	ACE_Future (const T &r)
	Constructor that initialises an ACE_Future to point to the result r immediately. More...
	~ACE_Future (void)
	Destructor. More...
void	operator= (const ACE_Future< T > &r)
	Assignment operator that binds this and r to the same ACE_Future_Rep. An ACE_Future_Rep is created if necessary. More...
int	cancel (const T &r)
	Cancel an ACE_Future and assign the value r. It is used if a client does not want to wait for the value to be produced. More...
int	cancel (void)
int	operator== (const ACE_Future< T > &r) const
int	operator!= (const ACE_Future< T > &r) const
	Inequality operator, which is the opposite of equality. More...
int	set (const T &r)
int	get (T &value, ACE_Time_Value *tv=0) const
	operator T ()
int	ready (void) const
	Check if the result is available. More...
int	attach (ACE_Future_Observer< T > *observer)
int	detach (ACE_Future_Observer< T > *observer)
void	dump (void) const
	Dump the state of an object. More...
ACE_Future_Rep< T > *	get_rep (void)
Public Attributes
	ACE_ALLOC_HOOK_DECLARE
	Declare the dynamic allocation hooks. More...
Private Types
typedef ACE_Future_Rep< T >	FUTURE_REP
	Protect operations on the <Future>. More...
Private Methods
void *	operator new (size_t nbytes)
	Do not allow new operator. More...
void	operator delete (void *)
	Do not allow delete operator. More...
void	operator & ()
	Do not allow address-of operator. More...
Private Attributes
FUTURE_REP *	future_rep_

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Detailed Description

template<class T>
class ACE_Future< T >

This class implements a ``single write, multiple read'' pattern that can be used to return results from asynchronous method invocations.

Definition at line 233 of file Future.h.

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Member Typedef Documentation

template<class T> typedef ACE_Future_Rep<T> ACE_Future::FUTURE_REP [private]

Protect operations on the <Future>. Definition at line 371 of file Future.h.

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Constructor & Destructor Documentation

template<class T> ACE_Future< T >::ACE_Future (  void    )

Constructor. Definition at line 282 of file Future.cpp. : future_rep_ (FUTURE_REP::create ()) { }

template<class T> ACE_Future< T >::ACE_Future (  const ACE_Future< T > &    r )

Copy constructor binds this and r to the same ACE_Future_Rep. An ACE_Future_Rep is created if necessary. Definition at line 288 of file Future.cpp. : future_rep_ (FUTURE_REP::attach (((ACE_Future<T> &) r).future_rep_)) { }

template<class T> ACE_Future< T >::ACE_Future (  const T &    r )

Constructor that initialises an ACE_Future to point to the result r immediately. Definition at line 294 of file Future.cpp. References ACE_DEBUG, ACE_LIB_TEXT, future_rep_, LM_DEBUG, and ACE_Future_Rep::set. : future_rep_ (FUTURE_REP::create ()) { ACE_DEBUG ((LM_DEBUG, ACE_LIB_TEXT (" (%t) funny constructor\n"))); this->future_rep_->set (r, *this); }

template<class T> ACE_Future< T >::~ACE_Future (  void    )

Destructor. Definition at line 304 of file Future.cpp. References future_rep_. { FUTURE_REP::detach (future_rep_); }

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Member Function Documentation

template<class T> int ACE_Future< T >::attach (  ACE_Future_Observer< T > *    observer )

Attaches the specified observer to a subject (this ACE_Future). The update method of the specified subject will be invoked with a copy of the associated ACE_Future as input when the result gets set. If the result is already set when this method gets invoked, then the update method of the specified subject will be invoked immediately. Parameters: observer  The observer to attach to the subject. Return values: 0  Success. 1  The observer was already attached. -1  Error; check ACE_OS::last_error() for an error code. Definition at line 363 of file Future.cpp. References ACE_Future_Rep::attach, and future_rep_. { return this->future_rep_->attach (observer, *this); }

template<class T> int ACE_Future< T >::cancel (  void    )

Cancel an ACE_Future. Put the future into its initial state. Returns 0 on succes and -1 on failure. It is now possible to reuse the ACE_Future. But remember, the ACE_Future is now bound to a new ACE_Future_Rep. Definition at line 330 of file Future.cpp. Referenced by cancel. { // If this ACE_Future is already attached to a ACE_Future_Rep, // detach it (maybe delete the ACE_Future_Rep). FUTURE_REP::assign (this->future_rep_, FUTURE_REP::create ()); return 0; }

template<class T> int ACE_Future< T >::cancel (  const T &    r )

Cancel an ACE_Future and assign the value r. It is used if a client does not want to wait for the value to be produced. Definition at line 322 of file Future.cpp. References cancel, future_rep_, and ACE_Future_Rep::set. { this->cancel (); return this->future_rep_->set (r, *this); }

template<class T> int ACE_Future< T >::detach (  ACE_Future_Observer< T > *    observer )

Detaches the specified observer from a subject (this ACE_Future). The update method of the specified subject will not be invoked when the ACE_Future_Rep result gets set. Parameters: observer  The observer to attach to the subject. Return values: 0  The observer was successfully detached. -1  Error, including the observer not attached prior to calling this method. Definition at line 369 of file Future.cpp. References ACE_Future_Rep::detach, and future_rep_. { return this->future_rep_->detach (observer); }

template<class T> void ACE_Future< T >::dump (  void    )  const

Dump the state of an object. Definition at line 406 of file Future.cpp. References ACE_BEGIN_DUMP, ACE_DEBUG, ACE_END_DUMP, ACE_Future_Rep::dump, future_rep_, and LM_DEBUG. { ACE_DEBUG ((LM_DEBUG, ACE_BEGIN_DUMP, this)); if (this->future_rep_) this->future_rep_->dump (); ACE_DEBUG ((LM_DEBUG, ACE_END_DUMP)); }

template<class T> int ACE_Future< T >::get (  T &    value, ACE_Time_Value *    tv = 0 )  const

Wait to get the object's value. Parameters: value  Receives the value of this ACE_Future when it is set. tv  Pointer to an ACE_Time_Value containing the absolute time to wait until for the value to be set. If tv is 0, the call waits indefinitely for the value to be set, unless an error occurs. Return values: 0  Success; value contains the value of the ACE_Future. -1  Error; check ACE_OS::last_error() for an error code. Definition at line 355 of file Future.cpp. References future_rep_, and ACE_Future_Rep::get. { // We return the ACE_Future_rep. return this->future_rep_->get (value, tv); }

template<class T> ACE_Future_Rep< T > * ACE_Future< T >::get_rep (  void    )

Get the underlying ACE_Future_Rep pointer. Note that this method should rarely, if ever, be used and that modifying the underlying ACE_Future_Rep should be done with extreme caution. Definition at line 419 of file Future.cpp. References future_rep_. Referenced by ACE_Future_Set::update. { return this->future_rep_; }

template<class T> void ACE_Future< T >::operator & (    )  [private]

Do not allow address-of operator. Definition at line 439 of file Future.cpp. { }

template<class T> void ACE_Future< T >::operator delete (  void *    )  [private]

Do not allow delete operator. Definition at line 434 of file Future.cpp. { }

template<class T> void * ACE_Future< T >::operator new (  size_t    nbytes )  [private]

Do not allow new operator. Definition at line 425 of file Future.cpp. References ACE_throw_bad_alloc. { ACE_throw_bad_alloc; #if defined (__HP_aCC) return 0; #endif /* 0 */ }

template<class T> ACE_Future< T >::operator T (    )

Deprecated: Note that this method is going away in a subsequent release since it doesn't distinguish between failure results and success results (exceptions should be used, but they aren't portable...). Type conversion, which obtains the result of the asynchronous method invocation. Will block forever. The get() method should be used instead since it separates the error value from the result, and also permits timeouts. Definition at line 375 of file Future.cpp. References future_rep_. { // note that this will fail (and COREDUMP!) // if future_rep_ == 0 ! // // but... // this is impossible unless somebody is so stupid to // try something like this: // // Future<T> futT; // T t; // t = futT; // perform type conversion on Future_Rep. return *future_rep_; }

template<class T> int ACE_Future< T >::operator!= (  const ACE_Future< T > &    r )  const

Inequality operator, which is the opposite of equality. Definition at line 316 of file Future.cpp. References future_rep_. { return r.future_rep_ != this->future_rep_; }

template<class T> void ACE_Future< T >::operator= (  const ACE_Future< T > &    r )

Assignment operator that binds this and r to the same ACE_Future_Rep. An ACE_Future_Rep is created if necessary. Definition at line 393 of file Future.cpp. References future_rep_. { // assignment: // // bind <this> to the same <ACE_Future_Rep> as <r>. // This will work if &r == this, by first increasing the ref count ACE_Future<T> &r = (ACE_Future<T> &) rhs; FUTURE_REP::assign (this->future_rep_, FUTURE_REP::attach (r.future_rep_)); }

template<class T> int ACE_Future< T >::operator== (  const ACE_Future< T > &    r )  const

Equality operator that returns 1 if both ACE_Future objects point to the same ACE_Future_Rep object. Attention: It also returns 1 if both objects have just been instantiated and not used yet. Definition at line 310 of file Future.cpp. References future_rep_. { return r.future_rep_ == this->future_rep_; }

template<class T> int ACE_Future< T >::ready (  void    )  const

Check if the result is available. Definition at line 348 of file Future.cpp. References future_rep_, and ACE_Future_Rep::ready. { // We're ready if the ACE_Future_rep is ready... return this->future_rep_->ready (); }

template<class T> int ACE_Future< T >::set (  const T &    r )

Make the result available. Is used by the server thread to give the result to all waiting clients. Returns 0 for success, -1 on failure. This function only has an effect the first time it is called for the object (actually, the first time the underlying ACE_Future_Rep has a value assigned to it). Subsequent calls return 0 (success) but have no effect. Definition at line 340 of file Future.cpp. References future_rep_, and ACE_Future_Rep::set. { // Give the pointer to the result to the ACE_Future_Rep. return this->future_rep_->set (r, *this); }

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Member Data Documentation

template<class T> ACE_Future::ACE_ALLOC_HOOK_DECLARE

Declare the dynamic allocation hooks. Definition at line 357 of file Future.h.

template<class T> FUTURE_REP* ACE_Future::future_rep_ [private]

Definition at line 372 of file Future.h. Referenced by ACE_Future, attach, cancel, detach, dump, get, get_rep, operator T, operator!=, operator=, operator==, ready, set, and ~ACE_Future.

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The documentation for this class was generated from the following files:

• Future.h
• Future.cpp

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