@Bean public IntegrationFlow fileReadingFlow() { return IntegrationFlows .from(s -> s.file(tmpDir.getRoot()) .patternFilter("*.sitest") .useWatchService(true) .watchEvents(FileReadingMessageSource.WatchEventType.CREATE, FileReadingMessageSource.WatchEventType.MODIFY), e -> e.poller(Pollers.fixedDelay(100) .errorChannel("filePollingErrorChannel"))) .filter(File.class, p -> !p.getName().startsWith("a"), e -> e.throwExceptionOnRejection(true)) .transform(Transformers.fileToString()) .aggregate(a -> a.correlationExpression("1") .releaseStrategy(g -> g.size() == 25)) .channel(MessageChannels.queue("fileReadingResultChannel")) .get(); }