Package com.google.common.util.concurrent

Class ForwardingFluentFuture<V>

java.lang.Object

com.google.common.util.concurrent.internal.InternalFutureFailureAccess

com.google.common.util.concurrent.AbstractFuture<V>

com.google.common.util.concurrent.GwtFluentFutureCatchingSpecialization<V>

com.google.common.util.concurrent.FluentFuture<V>

com.google.common.util.concurrent.ForwardingFluentFuture<V>

All Implemented Interfaces:

ListenableFuture<V>, java.util.concurrent.Future<V>

@GwtCompatible
final class ForwardingFluentFuture<V>
extends FluentFuture<V>

FluentFuture that forwards all calls to a delegate.

Extension

If you want a class like FluentFuture but with extra methods, we recommend declaring your own subclass of ListenableFuture, complete with a method like FluentFuture.from(com.google.common.util.concurrent.ListenableFuture<V>) to adapt an existing ListenableFuture, implemented atop a ForwardingListenableFuture that forwards to that future and adds the desired methods.

Nested Class Summary

Nested classes/interfaces inherited from class com.google.common.util.concurrent.FluentFuture

FluentFuture.TrustedFuture<V>

Nested classes/interfaces inherited from class com.google.common.util.concurrent.AbstractFuture

AbstractFuture.Trusted<V>

Field Summary

Fields

Modifier and Type	Field	Description
private ListenableFuture<V>	delegate

Constructor Summary

Constructors

Constructor	Description
ForwardingFluentFuture(ListenableFuture<V> delegate)

Method Summary

Modifier and Type	Method	Description
void	addListener(java.lang.Runnable listener, java.util.concurrent.Executor executor)	Registers a listener to be run on the given executor.
boolean	cancel(boolean mayInterruptIfRunning)
V	get()
V	get(long timeout, java.util.concurrent.TimeUnit unit)
boolean	isCancelled()
boolean	isDone()
java.lang.String	toString()

Methods inherited from class com.google.common.util.concurrent.FluentFuture

addCallback, catching, catchingAsync, from, from, transform, transformAsync, withTimeout, withTimeout

Methods inherited from class com.google.common.util.concurrent.AbstractFuture

afterDone, interruptTask, maybePropagateCancellationTo, pendingToString, set, setException, setFuture, tryInternalFastPathGetFailure, wasInterrupted

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

delegate

private final ListenableFuture<V> delegate

Constructor Detail

ForwardingFluentFuture

ForwardingFluentFuture(ListenableFuture<V> delegate)

Method Detail

addListener

public void addListener(java.lang.Runnable listener,
                        java.util.concurrent.Executor executor)

Description copied from class: AbstractFuture

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.

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(). Otherwise, avoid it. Heavyweight directExecutor listeners can cause problems, and these problems can be difficult to reproduce because they depend on timing. For example:

• The listener may be executed by the caller of addListener. That caller may be a UI thread or other latency-sensitive thread. This can harm UI responsiveness.
• The listener may be executed by the thread that completes this Future. That thread may be an internal system thread such as an RPC network thread. Blocking that thread may stall progress of the whole system. It may even cause a deadlock.
• The listener may delay other listeners, even listeners that are not themselves directExecutor listeners.

This is the most general listener interface. For common operations performed using listeners, see Futures. For a simplified but general listener interface, see addCallback().

Memory consistency effects: Actions in a thread prior to adding a listener happen-before its execution begins, perhaps in another thread.

Guava implementations of ListenableFuture promptly release references to listeners after executing them.

Specified by:

addListener in interface ListenableFuture<V>

Overrides:

addListener in class AbstractFuture<V>

Parameters:

listener - the listener to run when the computation is complete

executor - the executor to run the listener in

cancel

public boolean cancel(boolean mayInterruptIfRunning)

Description copied from class: AbstractFuture

If a cancellation attempt succeeds on a Future that had previously been set asynchronously, then the cancellation will also be propagated to the delegate Future that was supplied in the setFuture call.

Rather than override this method to perform additional cancellation work or cleanup, subclasses should override AbstractFuture.afterDone(), consulting AbstractFuture.isCancelled() and AbstractFuture.wasInterrupted() as necessary. This ensures that the work is done even if the future is cancelled without a call to cancel, such as by calling setFuture(cancelledFuture).

Specified by:

cancel in interface java.util.concurrent.Future<V>

Overrides:

cancel in class AbstractFuture<V>

isCancelled

public boolean isCancelled()

Specified by:

isCancelled in interface java.util.concurrent.Future<V>

Overrides:

isCancelled in class AbstractFuture<V>

isDone

public boolean isDone()

Specified by:

isDone in interface java.util.concurrent.Future<V>

Overrides:

isDone in class AbstractFuture<V>

get

public V get()
      throws java.lang.InterruptedException,
             java.util.concurrent.ExecutionException

Description copied from class: AbstractFuture

The default AbstractFuture implementation throws InterruptedException if the current thread is interrupted during the call, even if the value is already available.

Specified by:

get in interface java.util.concurrent.Future<V>

Overrides:

get in class AbstractFuture<V>

Throws:

java.lang.InterruptedException

java.util.concurrent.ExecutionException

get

public V get(long timeout,
             java.util.concurrent.TimeUnit unit)
      throws java.lang.InterruptedException,
             java.util.concurrent.ExecutionException,
             java.util.concurrent.TimeoutException

Description copied from class: AbstractFuture

The default AbstractFuture implementation throws InterruptedException if the current thread is interrupted during the call, even if the value is already available.

Specified by:

get in interface java.util.concurrent.Future<V>

Overrides:

get in class AbstractFuture<V>

Throws:

java.lang.InterruptedException

java.util.concurrent.ExecutionException

java.util.concurrent.TimeoutException

toString

public java.lang.String toString()

Overrides:

toString in class AbstractFuture<V>