com.google.common.util.concurrent
Class AbstractListenableFuture<V>

java.lang.Object
  com.google.common.util.concurrent.AbstractFuture<V>
      com.google.common.util.concurrent.AbstractListenableFuture<V>

All Implemented Interfaces:

ListenableFuture<V>, Future<V>

Direct Known Subclasses:

ValueFuture

@Beta
public abstract class AbstractListenableFuture<V>
extends AbstractFuture<V>
implements ListenableFuture<V>

An abstract base implementation of the listener support provided by ListenableFuture. This class uses an ExecutionList to guarantee that all registered listeners will be executed. Listener/Executor pairs are stored in the execution list and executed in the order in which they were added, but because of thread scheduling issues there is no guarantee that the JVM will execute them in order. In addition, listeners added after the task is complete will be executed immediately, even if some previously added listeners have not yet been executed.

This class uses the AbstractFuture class to implement the ListenableFuture interface and simply delegates the addListener(Runnable, Executor) and done() methods to it.

Since:

1

Author:

Sven Mawson

AbstractListenableFuture

public AbstractListenableFuture()

addListener

public void addListener(Runnable listener,
                        Executor exec)

Description copied from interface: ListenableFuture

Adds a listener and executor to the ListenableFuture. The listener will be passed to the executor for execution when the Future's computation is complete.

There is no guaranteed ordering of execution of listeners, they may get called in the order they were added and they may get called out of order, but any listener added through this method is guaranteed to be called once the computation is complete.

Specified by:

addListener in interface ListenableFuture<V>

Parameters:

listener - the listener to run when the computation is complete.

exec - the executor to run the listener in.

done

protected void done()

Overrides:

done in class AbstractFuture<V>