TaskExecutor is not working Spring Integration

Question

I have setup File poller with task executor

ExecutorService executorService = Executors.newFixedThreadPool(10);

            LOG.info("Setting up the poller for directory {} ", finalDirectory);
            StandardIntegrationFlow standardIntegrationFlow = IntegrationFlows.from(new CustomFileReadingSource(finalDirectory),
                    c -> c.poller(Pollers.fixedDelay(5, TimeUnit.SECONDS, 5)
                            .taskExecutor(executorService)
                            .maxMessagesPerPoll(10)
                            .advice(new LoggerSourceAdvisor(finalDirectory))
                    ))


                    //move file to processing first processing                    
                    .transform(new FileMoveTransformer("C:/processing", true))
                    .channel("fileRouter")
                    .get();

As seen I have setup fixed threadpool of 10 and maximum message 10 per poll. If I put 10 files it still processes one by one. What could be wrong here ?

* UPDATE *

It works perfectly fine after Gary's answer though I have other issue now.

I have setup my Poller like this

setDirectory(new File(path));
        DefaultDirectoryScanner scanner = new DefaultDirectoryScanner();

        scanner.setFilter(new AcceptAllFileListFilter<>());
        setScanner(scanner);

The reason of using AcceptAll because the same file may come again that's why I sort of move the file first. But when I enable the thread executor the same file is being processed by mutliple threads, I assume because of AcceptAllFile

If I Change to AcceptOnceFileListFilter it works but then the same file that comes again will not be picked up again ! What can be done to avoid this issue ?

Issue/Bug

In Class AbstractPersistentAcceptOnceFileListFilter We have this code

@Override
    public boolean accept(F file) {
        String key = buildKey(file);
        synchronized (this.monitor) {
            String newValue = value(file);
            String oldValue = this.store.putIfAbsent(key, newValue);
            if (oldValue == null) { // not in store
                flushIfNeeded();
                return true;
            }
            // same value in store
            if (!isEqual(file, oldValue) && this.store.replace(key, oldValue, newValue)) {
                flushIfNeeded();
                return true;
            }
            return false;
        }
    }

Now for example if I have setup max per poll 5 and there are two files then its possible same file would be picked up by two threads.

Lets say my code moves the files once I read it.

But the other thread gets to the accept method

if the file is not there then it will return lastModified time as 0 and it will return true.

That causes the issue because the file is NOT there.

If its 0 then it should return false as the file is not there anymore.

Answer 1

When you add a task executor to a poller; all that does is the scheduler thread hands the poll task off to a thread in the thread pool; the maxMessagesPerPoll is part of the poll task. The poller itself only runs once every 5 seconds. To get what you want, you should add an executor channel to the flow...

@SpringBootApplication
public class So53521593Application {

    private static final Logger logger = LoggerFactory.getLogger(So53521593Application.class);

    public static void main(String[] args) {
        SpringApplication.run(So53521593Application.class, args);
    }

    @Bean
    public IntegrationFlow flow() {
        ExecutorService exec = Executors.newFixedThreadPool(10);
        return IntegrationFlows.from(() -> "foo", e -> e
                    .poller(Pollers.fixedDelay(5, TimeUnit.SECONDS)
                            .maxMessagesPerPoll(10)))
                .channel(MessageChannels.executor(exec))
                .<String>handle((p, h) -> {
                    try {
                        logger.info(p);
                        Thread.sleep(10_000);
                    }
                    catch (InterruptedException e1) {
                        Thread.currentThread().interrupt();
                    }
                    return null;
                })
                .get();
    }
}

EDIT

It works fine for me...

@Bean
public IntegrationFlow flow() {
    ExecutorService exec = Executors.newFixedThreadPool(10);
    return IntegrationFlows.from(Files.inboundAdapter(new File("/tmp/foo")).filter(
                new FileSystemPersistentAcceptOnceFileListFilter(new SimpleMetadataStore(), "foo")),
                    e -> e.poller(Pollers.fixedDelay(5, TimeUnit.SECONDS)
                            .maxMessagesPerPoll(10)))
            .channel(MessageChannels.executor(exec))
            .handle((p, h) -> {
                try {
                    logger.info(p.toString());
                    Thread.sleep(10_000);
                }
                catch (InterruptedException e1) {
                    Thread.currentThread().interrupt();
                }
                return null;
            })
            .get();
}

and

2018-11-28 11:46:05.196 INFO 57607 --- [pool-1-thread-1] com.example.So53521593Application : /tmp/foo/test1.txt

2018-11-28 11:46:05.197 INFO 57607 --- [pool-1-thread-2] com.example.So53521593Application : /tmp/foo/test2.txt

and with touch test1.txt

2018-11-28 11:48:00.284 INFO 57607 --- [pool-1-thread-3] com.example.So53521593Application : /tmp/foo/test1.txt

EDIT1

Agreed - reproduced with this...

@Bean
public IntegrationFlow flow() {
    ExecutorService exec = Executors.newFixedThreadPool(10);
    return IntegrationFlows.from(Files.inboundAdapter(new File("/tmp/foo")).filter(
                new FileSystemPersistentAcceptOnceFileListFilter(new SimpleMetadataStore(), "foo")),
                    e -> e.poller(Pollers.fixedDelay(5, TimeUnit.SECONDS)
                            .maxMessagesPerPoll(10)))
            .channel(MessageChannels.executor(exec))
            .<File>handle((p, h) -> {
                try {
                    p.delete();
                    logger.info(p.toString());
                    Thread.sleep(10_000);
                }
                catch (InterruptedException e1) {
                    Thread.currentThread().interrupt();
                }
                return null;
            })
            .get();
}

and

2018-11-28 13:22:23.689 INFO 75681 --- [pool-1-thread-1] com.example.So53521593Application : /tmp/foo/test1.txt

2018-11-28 13:22:23.690 INFO 75681 --- [pool-1-thread-2] com.example.So53521593Application : /tmp/foo/test2.txt

2018-11-28 13:22:23.690 INFO 75681 --- [pool-1-thread-3] com.example.So53521593Application : /tmp/foo/test1.txt

2018-11-28 13:22:23.690 INFO 75681 --- [pool-1-thread-4] com.example.So53521593Application : /tmp/foo/test2.txt