WSO2 ESB - How to send response to Intermediate sequence from service provider? - wso2

Question

i was going through a video about "Webinar - ESB - An answer to Enterprise Service Integration" by WSO2 ESB . i have a doubt regarding the video .
it is said in the video that , always in sequence will receive the request and out sequence will return the response from the service provider . An ESb can have multiple intermediate sequence and we can, set to which intermediate sequence service provider has to send the response .
How is it possible when we do not have any control over the service provider ? are we using some queue in between ESB and service provider to accomplish ?

Answer 1

Inside a sequence, when you send a request to a service, you can choose the response-handling sequence (service chaining) :
<send receive="personInfoSeq">
<endpoint key="PersonInfoEpr"/>
</send>
When the ESB sends the request, a callback is instanciated (a dedicated thread) which will wait for the reply and then execute the 'receive' sequence configured in the 'send' mediator
Inside a sequence, when you are working with a response message, you can change it to a request message (<property name="RESPONSE" value="false"/>) and send it to another service
Inside a "in" sequence (when you are working with a request message), you can generate a response, sample :
<inSequence>
<header name="To" action="remove"/>
<property name="RESPONSE" value="true"/>
<property name="NO_ENTITY_BODY" scope="axis2" action="remove"/>
<payloadFactory>
<format>
<ns:getQuoteResponse xmlns:ns="http://services.samples">
<ns:return xmlns:ax21="http://services.samples/xsd">
<ax21:change>4.212070096051944</ax21:change>
<ax21:earnings>-9.567415587431361</ax21:earnings>
<ax21:high>-148.1740146577308</ax21:high>
<ax21:symbol>IBM</ax21:symbol>
</ns:return>
</ns:getQuoteResponse>
</format>
</payloadFactory>
<send/>
</inSequence>