com.google.common.util.concurrent
Class ListenableFutureTask<V>

java.lang.Object
  java.util.concurrent.FutureTask<V>
      com.google.common.util.concurrent.ListenableFutureTask<V>

All Implemented Interfaces:

ListenableFuture<V>, Runnable, Future<V>, RunnableFuture<V>

public final class ListenableFutureTask<V>
extends FutureTask<V>
implements ListenableFuture<V>

A FutureTask that also implements the ListenableFuture interface. Unlike FutureTask, ListenableFutureTask does not provide an overrideable done() method. For similar functionality, call addListener(java.lang.Runnable, java.util.concurrent.Executor).

Since:

1.0

Author:

Sven Mawson

Method Summary

void	addListener(Runnable listener, Executor exec) Registers a listener to be run on the given executor.
static <V> ListenableFutureTask<V>	create(Callable<V> callable) Creates a ListenableFutureTask that will upon running, execute the given Callable.
static <V> ListenableFutureTask<V>	create(Runnable runnable, V result) Creates a ListenableFutureTask that will upon running, execute the given Runnable, and arrange that get will return the given result on successful completion.
protected void	done() Internal implementation detail used to invoke the listeners.

Methods inherited from class java.util.concurrent.FutureTask

cancel, get, get, isCancelled, isDone, run, runAndReset, set, setException

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.concurrent.Future

cancel, get, get, isCancelled, isDone

Method Detail

create

public static <V> ListenableFutureTask<V> create(Callable<V> callable)

Creates a ListenableFutureTask that will upon running, execute the given Callable.

Parameters:

callable - the callable task

Since:

10.0

create

public static <V> ListenableFutureTask<V> create(Runnable runnable,
                                                 @Nullable
                                                 V result)

Creates a ListenableFutureTask that will upon running, execute the given Runnable, and arrange that get will return the given result on successful completion.

Parameters:

runnable - the runnable task

result - 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 the Future'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., a RejectedExecutionException or an exception thrown by inline execution) will be caught and logged.

Note: For fast, lightweight listeners that would be safe to execute in any thread, consider MoreExecutors.sameThreadExecutor(). For heavier listeners, sameThreadExecutor() carries some caveats: First, the thread that the listener runs in depends on whether the Future is done at the time it is added and on whether it is ever canclled. In particular, listeners may run in the thread that calls addListener or the thread that calls cancel. Second, listeners may run in an internal thread of the system responsible for the input Future, such as an RPC network thread. Finally, during the execution of a sameThreadExecutor() listener, all other registered but unexecuted listeners are prevented from running, even if those listeners are to run in other executors.

This is the most general listener interface. For common operations performed using listeners, see Futures

Specified by:

addListener in interface ListenableFuture<V>

Parameters:

listener - the listener to run when the computation is complete

exec - the executor to run the listener in

done

protected void done()

Internal implementation detail used to invoke the listeners.

Overrides:

done in class FutureTask<V>