Question

我试图为ListenableFutures设置一个嵌套的回调层，如下所示：

ListeningExecutorService service = MoreExecutors.listeningDecorator(Executors.newFixedThreadPool(10));

ListenableFuture<A> futureA = service.submit(() -> a.doSomething());

Futures.addCallback(futureA, new FutureCallback<A>() {
    @Override
    public void onSuccess(A result) {
         ListenableFuture<B> futureB = service.submit(() -> b.doSomething(result)
    }
});

如果futureA和futureB完成后如何添加回调？

这是一个简单的示例，但我正在寻找可能有多层ListenableFuture的解决方案。

Answer 1

可能选择使用allAsList创建新的未来。（我假设您不介意同时启动a和b。）

//No idea how A and B are related, so I assume Object
ListenableFuture<List<? extends Object>> futureAB = Futures.allAsList(futureA, futureB);
Futures.addCallback(futureAB, ...);

更新后：

ListeningExecutorService service = MoreExecutors.listeningDecorator(Executors.newFixedThreadPool(10));

ListenableFuture<A> futureA = service.submit(() -> a.doSomething());

Futures.addCallback(futureA, new FutureCallback<A>() {
    @Override
    public void onSuccess(final A result) {
         ListenableFuture<B> futureB = service.submit(() -> b.doSomething(result);
         Futures.addCallback(futureB, new FutureCallback<B>() {
              ©Override
              public void onSuccess(final B resultB) {
                  //Do something with result and resultB.
              }
         });
    }
});

在FutureCallback中启动ListenableFuture并在完成所有操作后回调

1 个答案: