DefaultFuture#doReceived should call done.signalAll instead of done.signal

[kexianjun]

in the method of org.apache.dubbo.remoting.exchange.support.DefaultFuture#doReceived, I think we should call done.signalAll() instead of done.signal() ,and it's unnecessary to check done != null because it's always true

private void doReceived(Response res) {
        lock.lock();
        try {
            response = res;
            if (done != null) {
                done.signal();
            }
        } finally {
            lock.unlock();
        }
        if (callback != null) {
            invokeCallback(callback);
        }
    }

[tswstarplanet]

Sounds good! signall can avoid dead lock better

[kexianjun]

Sounds good! signall can avoid dead lock better

yes, using signal can cause threads to block until a timeout in some scenarios

[xueshanyinyan]

阅读2.6.2版本的源码，觉得这个优化没必要吧，条件变量的等待队列里就一个线程，signal足够了，当然换成signalAll是没啥问题。是实际投入使用中出现了这样的问题吗？是什么样的问题呢？现在的版本已经使用CompletableFuture异步转同步了呢。

[LeroyPine]

为什么 signal 或导致线程阻塞呢？ DefaultFuture 不是和线程一一对应的。 不存在多线程竞争的关系吧