testTaskAddedAfterShutdownNotAbandoned() — netty Function Reference

Source Code

common/src/test/java/io/netty/util/concurrent/SingleThreadEventExecutorTest.java lines 482–549

    @Test
    public void testTaskAddedAfterShutdownNotAbandoned() throws Exception {

        // A queue that doesn't support remove, so tasks once added cannot be rejected anymore
        LinkedBlockingQueue<Runnable> taskQueue = new LinkedBlockingQueue<Runnable>() {
            @Override
            public boolean remove(Object o) {
                throw new UnsupportedOperationException();
            }
        };

        final Runnable dummyTask = new Runnable() {
            @Override
            public void run() {
            }
        };

        final LinkedBlockingQueue<Future<?>> submittedTasks = new LinkedBlockingQueue<Future<?>>();
        final AtomicInteger attempts = new AtomicInteger();
        final AtomicInteger rejects = new AtomicInteger();

        ExecutorService executorService = Executors.newSingleThreadExecutor();
        final SingleThreadEventExecutor executor = new SingleThreadEventExecutor(null, executorService, false,
                taskQueue, RejectedExecutionHandlers.reject()) {
            @Override
            protected void run() {
                while (!confirmShutdown()) {
                    Runnable task = takeTask();
                    if (task != null) {
                        task.run();
                    }
                }
            }

            @Override
            protected boolean confirmShutdown() {
                boolean result = super.confirmShutdown();
                // After shutdown is confirmed, scheduled one more task and record it
                if (result) {
                    attempts.incrementAndGet();
                    try {
                        submittedTasks.add(submit(dummyTask));
                    } catch (RejectedExecutionException e) {
                        // ignore, tasks are either accepted or rejected
                        rejects.incrementAndGet();
                    }
                }
                return result;
            }
        };

        // Start the loop
        executor.submit(dummyTask).sync();

        // Shutdown without any quiet period
        executor.shutdownGracefully(0, 100, TimeUnit.MILLISECONDS).sync();

        // Ensure there are no user-tasks left.
        assertEquals(0, executor.drainTasks());

        // Verify that queue is empty and all attempts either succeeded or were rejected
        assertTrue(taskQueue.isEmpty());
        assertTrue(attempts.get() > 0);
        assertEquals(attempts.get(), submittedTasks.size() + rejects.get());
        for (Future<?> f : submittedTasks) {
            assertTrue(f.isSuccess());
        }
    }