V- The result type returned by this Future's
public abstract class ForwardingListenableFuture<V> extends ForwardingFuture<V> implements ListenableFuture<V>
ListenableFuturewhich forwards all its method calls to another future. Subclasses should override one or more methods to modify the behavior of the backing future as desired per the decorator pattern.
Most subclasses can just use
|Modifier and Type||Class and Description|
A simplified version of
|Modifier||Constructor and Description|
Constructor for use by subclasses.
|Modifier and Type||Method and Description|
Registers a listener to be run on the given executor.
Returns the backing delegate instance that methods are forwarded to.
cancel, get, get, isCancelled, isDone
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
protected abstract ListenableFuture<V> delegate()
ForwardingSet.delegate(). Concrete subclasses override this method to supply the instance being decorated.
public void addListener(Runnable listener, Executor exec)
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
Note: For fast, lightweight listeners that would be safe to execute in
any thread, consider
MoreExecutors.sameThreadExecutor(). For heavier
sameThreadExecutor() carries some caveats. For
example, the listener may run on an unpredictable or undesirable thread:
Futureis done at the time
addListenerwill execute the listener inline.
Futureis not yet done,
addListenerwill schedule the listener to be run by the thread that completes this
Future, which may be an internal system thread such as an RPC network thread.
Also note that, regardless of which thread executes the
sameThreadExecutor() listener, all other registered but unexecuted
listeners are prevented from running during its execution, 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. For a simplified but general
listener interface, see
listener- the listener to run when the computation is complete
exec- the executor to run the listener in
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