testNotEndlessExecute() — netty Function Reference

Source Code

common/src/test/java/io/netty/util/concurrent/UnorderedThreadPoolEventExecutorTest.java lines 33–74

    @Test
    public void testNotEndlessExecute() throws Exception {
        UnorderedThreadPoolEventExecutor executor = new UnorderedThreadPoolEventExecutor(1);

        try {
            // Having the first task wait on an exchanger allow us to make sure that the lister on the second task
            // is not added *after* the promise completes. We need to do this to prevent a race where the second task
            // and listener are completed before the DefaultPromise.NotifyListeners task get to run, which means our
            // queue inspection might observe this task after the CountDownLatch opens.
            final Exchanger<Void> exchanger = new Exchanger<Void>();
            final CountDownLatch latch = new CountDownLatch(3);
            Runnable task = new Runnable() {
                @Override
                public void run() {
                    try {
                        exchanger.exchange(null);
                    } catch (InterruptedException e) {
                        throw new RuntimeException(e);
                    }
                    latch.countDown();
                }
            };
            executor.execute(task);
            Future<?> future = executor.submit(new Runnable() {
                @Override
                public void run() {
                    latch.countDown();
                }
            }).addListener((FutureListener<Object>) f -> latch.countDown());
            exchanger.exchange(null);
            latch.await();
            future.syncUninterruptibly();

            // Now just check if the queue stays empty multiple times. This is needed as the submit to execute(...)
            // by DefaultPromise may happen in an async fashion
            for (int i = 0; i < 10000; i++) {
                assertTrue(executor.getQueue().isEmpty());
            }
        } finally {
            executor.shutdownGracefully();
        }
    }