- java.lang.Object
-
- java.util.concurrent.FutureTask<V>
-
- com.google.common.util.concurrent.ListenableFutureTask<V>
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- All Implemented Interfaces:
ListenableFuture<V>
,Runnable
,Future<V>
,RunnableFuture<V>
@GwtIncompatible public class ListenableFutureTask<V extends @Nullable Object> extends FutureTask<V> implements ListenableFuture<V>
AFutureTask
that also implements theListenableFuture
interface. UnlikeFutureTask
,ListenableFutureTask
does not provide an overrideabledone()
method. For similar functionality, calladdListener(java.lang.Runnable, java.util.concurrent.Executor)
.Few users should use this class. It is intended primarily for those who are implementing an
ExecutorService
. Most users should callListeningExecutorService.submit
on a service obtained fromMoreExecutors.listeningDecorator(java.util.concurrent.ExecutorService)
.- Since:
- 1.0
- Author:
- Sven Mawson
-
-
Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description void
addListener(Runnable listener, Executor exec)
Registers a listener to be run on the given executor.static <V extends @Nullable Object>
ListenableFutureTask<V>create(Runnable runnable, V result)
Creates aListenableFutureTask
that will upon running, execute the givenRunnable
, and arrange thatget
will return the given result on successful completion.static <V extends @Nullable Object>
ListenableFutureTask<V>create(Callable<V> callable)
Creates aListenableFutureTask
that will upon running, execute the givenCallable
.protected void
done()
Internal implementation detail used to invoke the listeners.V
get(long timeout, TimeUnit unit)
Waits if necessary for at most the given time for the computation to complete, and then retrieves its result, if available.-
Methods inherited from class java.util.concurrent.FutureTask
cancel, get, isCancelled, isDone, run, runAndReset, set, setException, toString
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
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Methods inherited from interface java.util.concurrent.Future
cancel, get, isCancelled, isDone
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-
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Method Detail
-
create
public static <V extends @Nullable Object> ListenableFutureTask<V> create(Callable<V> callable)
Creates aListenableFutureTask
that will upon running, execute the givenCallable
.- Parameters:
callable
- the callable task- Since:
- 10.0
-
create
public static <V extends @Nullable Object> ListenableFutureTask<V> create(Runnable runnable, V result)
Creates aListenableFutureTask
that will upon running, execute the givenRunnable
, and arrange thatget
will return the given result on successful completion.- Parameters:
runnable
- the runnable taskresult
- the result to return on successful completion. If you don't need a particular result, consider using constructions of the form:ListenableFuture<?> f = ListenableFutureTask.create(runnable, null)
- Since:
- 10.0
-
addListener
public void addListener(Runnable listener, Executor exec)
Description copied from interface:ListenableFuture
Registers a listener to be run on the given executor. The listener will run when theFuture
's computation is complete or, if the computation is already complete, immediately.There is no guaranteed ordering of execution of listeners, but any listener added through this method is guaranteed to be called once the computation is complete.
Exceptions thrown by a listener will be propagated up to the executor. Any exception thrown during
Executor.execute
(e.g., aRejectedExecutionException
or an exception thrown by direct execution) will be caught and logged.Note: If your listener is lightweight -- and will not cause stack overflow by completing more futures or adding more
directExecutor()
listeners inline -- considerMoreExecutors.directExecutor()
. Otherwise, avoid it: See the warnings on the docs fordirectExecutor
.This is the most general listener interface. For common operations performed using listeners, see
Futures
. For a simplified but general listener interface, seeaddCallback()
.Memory consistency effects: Actions in a thread prior to adding a listener happen-before its execution begins, perhaps in another thread.
Guava implementations of
ListenableFuture
promptly release references to listeners after executing them.- Specified by:
addListener
in interfaceListenableFuture<V extends @Nullable Object>
- Parameters:
listener
- the listener to run when the computation is completeexec
- the executor to run the listener in
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get
@CanIgnoreReturnValue public V get(long timeout, TimeUnit unit) throws TimeoutException, InterruptedException, ExecutionException
Description copied from interface:java.util.concurrent.Future
Waits if necessary for at most the given time for the computation to complete, and then retrieves its result, if available.- Specified by:
get
in interfaceFuture<V extends @Nullable Object>
- Overrides:
get
in classFutureTask<V extends @Nullable Object>
- Parameters:
timeout
- the maximum time to waitunit
- the time unit of the timeout argument- Returns:
- the computed result
- Throws:
TimeoutException
- if the wait timed outInterruptedException
- if the current thread was interrupted while waitingExecutionException
- if the computation threw an exception
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