Spring Integration: call service when flow completes - spring-integration

Question

I have a Spring Itegration (5.0.2) flow that reads data from an HTTP endpoint and publish Kafka messages using the (split) data from the HTTP response.
I would like to execute a "final" action before the flow completes, some sort of "try, catch, finally" but I'm not sure what is the best way to achieve this.
This is my code:
#Bean
public IntegrationFlow startFlow() {
return IntegrationFlows.from(() -> new GenericMessage<>(""),
c -> c.id("flow1")
.poller(
Pollers.fixedDelay(period, TimeUnit.MILLISECONDS, initialDelay).taskExecutor(taskExecutor)))
.handle(Http.outboundGateway("http://....)
.charset("UTF-8")
.expectedResponseType(String.class)
.httpMethod(HttpMethod.GET))
.transform(new transformer())
.split()
.channel(CHANNEL_1)
.controlBus()
.get();
}
#Bean
public IntegrationFlow toKafka(KafkaTemplate<?, ?> kafkaTemplate) {
return IntegrationFlows.from(CHANNEL_1)
.handle(Kafka.outboundChannelAdapter(kafkaTemplate)
// KAFKA SPECIFIC
.get();
}
Essentially, when all the messages have been sent (note that I'm using .split), I need to call a Spring bean to update some data.
Thanks

Answer 1

If you talk about "when all the messages" after splitter, then you need to take a look into an .aggregate(): https://docs.spring.io/spring-integration/docs/5.0.3.RELEASE/reference/html/messaging-routing-chapter.html#aggregator.
The splitter populates special sequence details headers into each splitted item and an aggregator is able to gather them to a single entity by default using those headers from received message.
Since you talk about the process after sending to Kafka, you should make your CHANNEL_1 as a PublishSubscribeChannel and have the mentioned .aggregate() as the last subscriber to this channel. The service to update some data should be already after this aggregator.