io.openmessaging

Interface Future<V>

All Known Subinterfaces:

Promise<V>

public interface 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. Additional methods are provided to determine if the task completed normally or was cancelled.

Since:

OMS 1.0.0

Version:

OMS 1.0.0

Method Summary

Modifier and Type	Method and Description
void	addListener(FutureListener<V> listener) Adds the specified listener to this future.
V	get() Waits if necessary for the computation to complete, and then retrieves its result.
V	get(long timeout) Waits if necessary for at most the given time for the computation to complete, and then retrieves its result, if available.
Throwable	getThrowable() Returns the cause of the failed future
boolean	isCancelled() Returns true if this task was cancelled before it completed normally.
boolean	isDone() Returns true if this task completed.

Method Detail

isCancelled

boolean isCancelled()

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

Returns:

true if this task was cancelled before it completed

isDone

boolean isDone()

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

get

V get()

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

Returns:

the computed result

get

V get(long timeout)

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

Returns:

the computed result

if the computation was cancelled

addListener

void addListener(FutureListener<V> listener)

Adds the specified listener to this future. The specified listener is notified when this future is done. If this future is already completed, the specified listener will be notified immediately.

Parameters:

listener - FutureListener

getThrowable

Throwable getThrowable()

Returns the cause of the failed future

Returns:

the cause of the failure. null if succeeded or this future is not completed yet.