Class ForwardingListenableFuture<V>

  extended by
      extended by<V>
          extended by<V>
Type Parameters:
V - The result type returned by this Future's get method
All Implemented Interfaces:
ListenableFuture<V>, Future<V>
Direct Known Subclasses:
ForwardingCheckedFuture, ForwardingListenableFuture.SimpleForwardingListenableFuture

public abstract class ForwardingListenableFuture<V>
extends ForwardingFuture<V>
implements ListenableFuture<V>

A ForwardingListenableFuture.SimpleForwardingListenableFuture which 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 ForwardingListenableFuture.SimpleForwardingListenableFuture.

Shardul Deo

Nested Class Summary
static class ForwardingListenableFuture.SimpleForwardingListenableFuture<V>
          A simplified version of ForwardingListenableFuture where subclasses can pass in an already constructed ListenableFuture as the delegate.
Nested classes/interfaces inherited from class
Constructor Summary
protected ForwardingListenableFuture()
          Constructor for use by subclasses.
Method Summary
 void addListener(Runnable listener, Executor exec)
          Registers a listener to be run on the given executor.
protected abstract  ListenableFuture<V> delegate()
          Returns the backing delegate instance that methods are forwarded to.
Methods inherited from class
cancel, get, get, isCancelled, isDone
Methods inherited from class
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
Methods inherited from interface java.util.concurrent.Future
cancel, get, get, isCancelled, isDone

Constructor Detail


protected ForwardingListenableFuture()
Constructor for use by subclasses.

Method Detail


protected abstract ListenableFuture<V> delegate()
Description copied from class: ForwardingObject
Returns 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.

Specified by:
delegate in class ForwardingFuture<V>


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.

Listeners cannot throw checked exceptions and should not throw RuntimeException unless their executors are prepared to handle it. Listeners that will execute in MoreExecutors.sameThreadExecutor() should take special care, since they may run during the call to addListener or during the call that sets the future's value.

Specified by:
addListener in interface ListenableFuture<V>
listener - the listener to run when the computation is complete
exec - the executor to run the listener in