等待所有任务完成(Waiting for all the tasks to finish)

 我使用相同的线程池完成了一系列不同的“任务”。 我想测量执行每项任务所需的时间，但为此我需要等待“任务”中的每项任务（抱歉模棱两可）才能完成。 
 
 当我只做一个任务时，我通常会这样做： 
 
ExecutorService e = Executors.newCachedThreadPool();
for (int i=0; i<100; ++i)
    e.submit(target);
e.shutdown();
while (!e.isTerminated());
 
 但由于将有几个任务提交到池中，我不能失望。 与等待任务完成提及“关闭请求后”有关的所有方法。 那么，如果我不想关闭它，但是等待所有线程完成然后提交更多任务呢？ 
 
 这就是我想要做的： 
 
ExecutorService e = Executors.newCachedThreadPool();
for (int i=0; i<100; ++i)
    e.submit(target);
// wait for all targets to finish
for (int i=0; i<100; ++i)
    e.submit(target); // submit different tasks
// wait... and so on
 
 我想过关闭池然后再使用prestartAllCoreThreads “唤醒它”，但后来我意识到这不是ExecutorService方法而是ThreadPoolExecutor方法。 这可能是一个解决方案吗？ 关闭它，等待，然后再次激活池？ 对我来说似乎有点难看。 
 
 我还认为最自然的事情是使用CyclicBarrier ，但这似乎是一种特定的方式，而我认为能够使用任何ExecutorService进行我正在尝试的事情是最合乎逻辑的事情。去做。 
 
 有什么方法可以坚持ExecutorService并等待所有任务完成？ 

I have a series of different "tasks" to be done using the same thread pool. I want to measure the time it takes to perform each task, but for that I need to wait for every task in the "task" (sorry for ambiguity) to finish.
 
When there's just one task I would normally do this:
 
ExecutorService e = Executors.newCachedThreadPool();
for (int i=0; i<100; ++i)
    e.submit(target);
e.shutdown();
while (!e.isTerminated());
 
But since there will be several task submitted to the pool, I can't it down. All the methods that have something to do with waiting for the tasks to finish mention "after shutdown request". Well, what if I don't want to shut it down, but wait for all the threads to finish and then submit more tasks?
 
This is what I want to do:
 
ExecutorService e = Executors.newCachedThreadPool();
for (int i=0; i<100; ++i)
    e.submit(target);
// wait for all targets to finish
for (int i=0; i<100; ++i)
    e.submit(target); // submit different tasks
// wait... and so on
 
I thought of shutting the pool down and then "waking it up" again using prestartAllCoreThreads, but then I realized this was not an ExecutorService method but a ThreadPoolExecutor method. Could this be a solution? Shutting it down, waiting, and then activating the pool again? Seems a bit ugly to me.
 
I also thought that the most natural thing to do was to use a CyclicBarrier, but it seems too a specific way of doing this, while I think it would be the most logical thing to be able to use any ExecutorService for what I'm trying to do.
 
Is there any way I could stick to ExecutorServices and wait for all the tasks to finish?

原文：https://stackoverflow.com/questions/24362798