How to aggregate the responses of two web services using spring integration - soap

Question

I am calling two webservices using spring-integration as shown below:
application-context.xml
<int:chain input-channel="requestChannelForHolidayService"
output-channel="outputChannelForHolidayService">
<int-ws:outbound-gateway
uri="http://localhost:8080/holidayService/holidayService" marshaller="marshaller"
unmarshaller="marshaller" />
</int:chain>
<int:chain input-channel="requestChannelForAccount"
output-channel="outputChannelForAccount">
<int-ws:outbound-gateway
uri="http://localhost:8080/spring-webservices-sample/endpoints"
marshaller="marshaller1" unmarshaller="marshaller1" />
</int:chain>
Testrunner.java
ApplicationContext context = new ClassPathXmlApplicationContext("application-context.xml");
MessageChannel channel=(MessageChannel) context.getBean("requestChannelForHolidayService",MessageChannel.class);
HolidayRequest request=new HolidayRequest();
BigInteger b1=new BigInteger("1");
BigInteger b2=new BigInteger("50");
request.setEmpId(b1);
request.setDays(b2);
System.out.println("sending request");
System.out.println("request sent");
channel.send(MessageBuilder.withPayload(request).build());
ApplicationContext context1 = new ClassPathXmlApplicationContext("application-context.xml");
MessageChannel channel1=(MessageChannel) context1.getBean("requestChannelForAccount",MessageChannel.class);
AccountDetailsRequest request2=new AccountDetailsRequest();
request2.setAccountNumber("12345");
System.out.println("sending request2");
System.out.println("request sent2");
channel1.send(MessageBuilder.withPayload(request2).build());
Now I need to combine the output of 'outputChannelForHolidayService' and 'outputChannelForAccount'.Can anyone help out for acheiving this. Thank you in advance.

Answer 1

You shouldn't use two application contexts; put them in the same context. Set the correlationId header on the messages; send both results to an aggregator with release-strategy-expression="size == 2".
Consider using a Messaging Gateway instead of sending to channels. Something like:
Collection<Object> process(#Payload Object[] requests, #Header("correlationId"), String correlation);
Then in the context, have...
gateway->splitter->payload-type-router->
request1Channel->ws->toAgg
request2Channel->ws->toAgg
toAggChannel->aggregator
If you omit the output-channel from the aggregator, the result will go back to the gateway.