decaf::util::concurrent::Future< V > Class Template Reference

A Future represents the result of an asynchronous computation. More...

#include <src/main/decaf/util/concurrent/Future.h>

Public Member Functions
virtual	~Future ()
virtual bool	cancel (bool mayInterruptIfRunning)=0
	Attempts to cancel execution of this task.
virtual bool	isCancelled () const =0
	Returns true if this task was canceled before it completed normally.
virtual bool	isDone () const =0
	Returns true if this task completed.
virtual V	get ()=0
	Waits if necessary for the computation to complete, and then retrieves its result.
virtual V	get (long long timeout, const TimeUnit &unit)=0
	Waits if necessary for at most the given time for the computation to complete, and then retrieves its result, if available.

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Detailed Description

template<typename V>
class decaf::util::concurrent::Future< V >

A Future represents the result of an asynchronous computation.

Methods are provided to check if the computation is complete, to wait for its completion, and to retrieve the result of the computation. The result can only be retrieved using method get when the computation has completed, blocking if necessary until it is ready. Cancellation is performed by the cancel method. Additional methods are provided to determine if the task completed normally or was canceled. Once a computation has completed, the computation cannot be canceled. If you would like to use a Future for the sake of cancellability but not provide a usable result, you can declare types of the form Future<void*> and return null as a result of the underlying task.

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Constructor & Destructor Documentation

template<typename V >

virtual decaf::util::concurrent::Future< V >::~Future

(

)

[inline, virtual]

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Member Function Documentation

template<typename V >

virtual bool decaf::util::concurrent::Future< V >::cancel

(

bool

mayInterruptIfRunning

)

[pure virtual]

Attempts to cancel execution of this task.

This attempt will fail if the task has already completed, has already been canceled, or could not be canceled for some other reason. If successful, and this task has not started when cancel is called, this task should never run. If the task has already started, then the mayInterruptIfRunning parameter determines whether the thread executing this task should be interrupted in an attempt to stop the task.

After this method returns, subsequent calls to isDone() will always return true. Subsequent calls to isCancelled() will always return true if this method returned true.

Parameters:

mayInterruptIfRunning

- true if the thread executing this task should be interrupted; otherwise, in-progress tasks are allowed to complete.

Returns:

false if the task could not be canceled, typically because it has already completed normally; true otherwise

template<typename V >

virtual V decaf::util::concurrent::Future< V >::get	(	long long	timeout,
		const TimeUnit &	unit
	)		[pure virtual]

Waits if necessary for at most the given time for the computation to complete, and then retrieves its result, if available.

Parameters:

timeout	- the maximum time to wait
unit	- the time unit of the timeout argument

Returns:

the computed result

Exceptions:

CancellationException	- if the computation was canceled
ExecutionException	- if the computation threw an exception
InterruptedException	- if the current thread was interrupted while waiting
TimeoutException	- if the wait timed out

template<typename V >

virtual V decaf::util::concurrent::Future< V >::get

(

)

[pure virtual]

Waits if necessary for the computation to complete, and then retrieves its result.

Returns:

the computed result.

Exceptions:

CancellationException	- if the computation was canceled
ExecutionException	- if the computation threw an exception
InterruptedException	- if the current thread was interrupted while waiting

template<typename V >

virtual bool decaf::util::concurrent::Future< V >::isCancelled

(

)

const [pure virtual]

Returns true if this task was canceled before it completed normally.

Returns:

true if this task was canceled before it completed

template<typename V >

virtual bool decaf::util::concurrent::Future< V >::isDone

(

)

const [pure virtual]

Returns true if this task completed.

Completion may be due to normal termination, an exception, or cancellation -- in all of these cases, this method will return true.

Returns:

true if this task completed

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

• src/main/decaf/util/concurrent/Future.h