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.
The reason for adding this future is mainly to satisfy the old version of jdk, such as jdk 1.6.
Modifier and Type | Method and Description |
---|---|
void |
addListener(FutureListener<V> listener)
Adds the specified listener to this future.
|
boolean |
cancel(boolean mayInterruptIfRunning)
Attempts to cancel execution of this task.
|
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. |
boolean cancel(boolean mayInterruptIfRunning)
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
.
mayInterruptIfRunning
- true
if the thread executing this
task should be interrupted; otherwise, in-progress tasks are allowed
to completefalse
if the task could not be cancelled,
typically because it has already completed normally;
true
otherwiseboolean isCancelled()
true
if this task was cancelled before it completed normally.true
if this task was cancelled before it completedboolean isDone()
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
.
true
if this task completedV get()
V get(long timeout)
timeout
- the maximum time to waitif the computation was cancelled
void addListener(FutureListener<V> listener)
listener
- FutureListenerThrowable getThrowable()
null
if succeeded or this future is not completed yet.Copyright © 2017–2020 OpenMessaging. All rights reserved.