Retry on timeout in a long process gateway

TimeoutGatewayFlowConfig.java

@Configuration
public class TimeoutGatewayFlowConfig extends IntegrationFlowAdapter {

    @Bean
    @Override
    protected IntegrationFlowDefinition<?> buildFlow() {
        return this
                .from(this.timeSource(), c -> c.poller(Pollers.fixedDelay(1, TimeUnit.MINUTES)))
                .gateway(this.longProcessFlow(), c -> c
                        .replyTimeout(TimeUnit.SECONDS.toMillis(5))
                        .requiresReply(true)
                        .advice(this.retryInterceptor())
                )
                .handle(m -> System.out.printf("Result:%s%n", m.getPayload()));
    }

    MessageSource<LocalDateTime> timeSource() {
        return () -> new GenericMessage<>(LocalDateTime.now());
    }

    IntegrationFlow longProcessFlow() {
        return f -> f
            .channel(MessageChannels.executor(Executors.newSingleThreadExecutor()))
            .handle((p, h) -> {                
                Exceptions.unchecked(() -> TimeUnit.SECONDS.sleep(10));
                return "Done!";
            });
    }

    private RetryOperationsInterceptor retryInterceptor() {
        RetryOperationsInterceptor interceptor = new RetryOperationsInterceptor();

        interceptor.setRetryOperations(this.retryTemplate());

        return interceptor;
    }

    private RetryTemplate retryTemplate() {
        RetryTemplate retryTemplate = new RetryTemplate();

        retryTemplate.setRetryPolicy(this.retryPolicy());
        retryTemplate.setBackOffPolicy(this.backoffPolicy());

        return retryTemplate;
    }

    private RetryPolicy retryPolicy() {
        return new SimpleRetryPolicy(10, ImmutableMap.of(ReplyRequiredException.class, true), true);
    }

    private BackOffPolicy backoffPolicy() {
        FixedBackOffPolicy backOffPolicy = new FixedBackOffPolicy();

        backOffPolicy.setBackOffPeriod(TimeUnit.SECONDS.toMillis(5));

        return backOffPolicy;
    }
}