- Direct Known Subclasses:
@CanIgnoreReturnValue @GwtCompatible public abstract class ForwardingListenableFuture<V> extends ForwardingFuture<V> implements ListenableFuture<V>A
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
- Shardul Deo
Nested Class Summary
Nested Classes Modifier and Type Class Description
Constructors Modifier Constructor Description
ForwardingListenableFuture()Constructor for use by subclasses.
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description
addListener(Runnable listener, Executor exec)Registers a listener to be run on the given executor.
protected abstract ListenableFuture<? extends V>
delegate()Returns the backing delegate instance that methods are forwarded to.
Methods inherited from class com.google.common.util.concurrent.ForwardingFuture
cancel, get, get, isCancelled, isDone
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
protected ForwardingListenableFuture()Constructor for use by subclasses.
protected abstract ListenableFuture<? extends V> delegate()Description copied from class:
ForwardingObjectReturns the backing delegate instance that methods are forwarded to. Abstract subclasses generally override this method with an abstract method that has a more specific return type, such as
ForwardingSet.delegate(). Concrete subclasses override this method to supply the instance being decorated.
public void addListener(Runnable listener, Executor exec)Description copied from interface:
ListenableFutureRegisters 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
RejectedExecutionExceptionor 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 -- consider
MoreExecutors.directExecutor(). Otherwise, avoid it: See the warnings on the docs for
Memory consistency effects: Actions in a thread prior to adding a listener happen-before its execution begins, perhaps in another thread.
Guava implementations of
ListenableFuturepromptly release references to listeners after executing them.