V - The result type returned by this Future's get methodpublic abstract class ForwardingListenableFuture<V> extends ForwardingFuture<V> implements ListenableFuture<V>
ListenableFuture 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.
| Modifier and Type | Class and Description |
|---|---|
static class |
ForwardingListenableFuture.SimpleForwardingListenableFuture<V>
A simplified version of
ForwardingListenableFuture where subclasses
can pass in an already constructed ListenableFuture
as the delegate. |
ForwardingFuture.SimpleForwardingFuture<V>| Modifier | Constructor and Description |
|---|---|
protected |
ForwardingListenableFuture()
Constructor for use by subclasses.
|
| Modifier and Type | Method and Description |
|---|---|
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.
|
cancel, get, get, isCancelled, isDonetoStringprotected ForwardingListenableFuture()
protected abstract ListenableFuture<V> delegate()
ForwardingObjectForwardingSet.delegate(). Concrete subclasses override this method to supply
the instance being decorated.delegate in class ForwardingFuture<V>public void addListener(Runnable listener, Executor exec)
ListenableFutureFuture'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. For
example, the listener may run on an unpredictable or undesirable thread:
Future is done at the time addListener is
called, addListener will execute the listener inline.
Future is not yet done, addListener will
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 addCallback().
addListener in interface ListenableFuture<V>listener - the listener to run when the computation is completeexec - the executor to run the listener inCopyright © 2010-2014. All Rights Reserved.