private static class JdkFutureAdapters.ListenableFutureAdapter<V> extends ForwardingFuture<V> implements ListenableFuture<V>
Future
into a ListenableFuture
. This
will wait on the future to finish, and when it completes, run the
listeners. This implementation will wait on the source future
indefinitely, so if the source future never completes, the adapter will
never complete either.
If the delegate future is interrupted or throws an unexpected unchecked exception, the listeners will not be invoked.
ForwardingFuture.SimpleForwardingFuture<V>
Modifier and Type | Field and Description |
---|---|
private java.util.concurrent.Executor |
adapterExecutor |
private static java.util.concurrent.Executor |
defaultAdapterExecutor |
private java.util.concurrent.Future<V> |
delegate |
private ExecutionList |
executionList |
private java.util.concurrent.atomic.AtomicBoolean |
hasListeners |
private static java.util.concurrent.ThreadFactory |
threadFactory |
Constructor and Description |
---|
ListenableFutureAdapter(java.util.concurrent.Future<V> delegate) |
ListenableFutureAdapter(java.util.concurrent.Future<V> delegate,
java.util.concurrent.Executor adapterExecutor) |
Modifier and Type | Method and Description |
---|---|
void |
addListener(java.lang.Runnable listener,
java.util.concurrent.Executor exec)
Registers a listener to be run on
the given executor.
|
protected java.util.concurrent.Future<V> |
delegate()
Returns the backing delegate instance that methods are forwarded to.
|
cancel, get, get, isCancelled, isDone
toString
private static final java.util.concurrent.ThreadFactory threadFactory
private static final java.util.concurrent.Executor defaultAdapterExecutor
private final java.util.concurrent.Executor adapterExecutor
private final ExecutionList executionList
private final java.util.concurrent.atomic.AtomicBoolean hasListeners
private final java.util.concurrent.Future<V> delegate
ListenableFutureAdapter(java.util.concurrent.Future<V> delegate)
ListenableFutureAdapter(java.util.concurrent.Future<V> delegate, java.util.concurrent.Executor adapterExecutor)
protected java.util.concurrent.Future<V> delegate()
ForwardingObject
ForwardingSet.delegate()
. Concrete subclasses override this method to supply
the instance being decorated.delegate
in class ForwardingFuture<V>
public void addListener(java.lang.Runnable listener, java.util.concurrent.Executor exec)
ListenableFuture
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 direct execution) will be caught and
logged.
Note: For fast, lightweight listeners that would be safe to execute in
any thread, consider MoreExecutors.directExecutor()
. For heavier
listeners, directExecutor()
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
directExecutor()
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 in