ListenableFuture

1. ListenableFuture

We strongly advise that you always use ListenableFuture instead of Future in all of your code, because:

• Most Futures methods require it.
• It's easier than changing to ListenableFuture later.
• Providers of utility methods won't need to provide Future and ListenableFuture variants of their methods.

2. Callbacks

A FutureCallback<V> implements two methods:

• onSuccess(V), the action to perform if the future succeeds, based on its result
• onFailure(Throwable), the action to perform if the future fails, based on the failure

3. Creation

ListeningExecutorService service = MoreExecutors.listeningDecorator(Executors.newFixedThreadPool(10));
ListenableFuture<Explosion> explosion = service.submit(new Callable<Explosion>() {
  public Explosion call() {
    return pushBigRedButton();
  }
});
Futures.addCallback(explosion, new FutureCallback<Explosion>() {
  // we want this handler to run immediately after we push the big red button!
  public void onSuccess(Explosion explosion) {
    walkAwayFrom(explosion);
  }
  public void onFailure(Throwable thrown) {
    battleArchNemesis(); // escaped the explosion!
  }
});

4.Application