MuleSoft Application Development With JMS Queue Explained: Part Two

Introduction

In the first part, I have covered the basic setup of mule flows using queues to publish and consume JMS messages. In this part, I will cover request-response exchange pattern. Basically we want to publish a message to a JMS queue and then wait for reply from the consumer. The details about how this can be achieved using Java are clearly described at this article
http://activemq.apache.org/how-should-i-implement-request-response-with-jms.html

The Message Producer Configuration

The mule configuration for JMS endpoints has the exchange pattern of one-way or request-response. Check the request-response button as show in the figure below:

The XML configuration looks like the following:

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1 2	<jms:outbound-endpoint exchange-pattern="request-response" queue="queueOne" connector-ref="Active_MQ" doc:name="Order Queue Producer"> </jms:outbound-endpoint>

Mule Flow Configuration

In order to demonstrate the request-response pattern, I created two flows, as shown in the following figure:

The corresponding XML configuration is listed as the following:

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<!--xml version="1.0" encoding="UTF-8"?-->   <mule xmlns:tracking="http://www.mulesoft.org/schema/mule/ee/tracking" xmlns:dw="http://www.mulesoft.org/schema/mule/ee/dw" xmlns:http="http://www.mulesoft.org/schema/mule/http" xmlns:jms="http://www.mulesoft.org/schema/mule/jms" xmlns="http://www.mulesoft.org/schema/mule/core" xmlns:doc="http://www.mulesoft.org/schema/mule/documentation" xmlns:spring="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemalocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-current.xsd http://www.mulesoft.org/schema/mule/core http://www.mulesoft.org/schema/mule/core/current/mule.xsd http://www.mulesoft.org/schema/mule/http http://www.mulesoft.org/schema/mule/http/current/mule-http.xsd http://www.mulesoft.org/schema/mule/jms http://www.mulesoft.org/schema/mule/jms/current/mule-jms.xsd http://www.mulesoft.org/schema/mule/ee/dw http://www.mulesoft.org/schema/mule/ee/dw/current/dw.xsd http://www.mulesoft.org/schema/mule/ee/tracking http://www.mulesoft.org/schema/mule/ee/tracking/current/mule-tracking-ee.xsd">     <flow name="request-response-main_Flow">         <http:listener config-ref="HTTP_Listener_Configuration" path="/jms/twoway" allowedmethods="POST" doc:name="HTTP">         <dw:transform-message doc:name="Json To Java">             <dw:set-payload><!--[CDATA[%dw 1.0 %output application/java --- payload]]--></dw:set-payload>         </dw:transform-message>         <set-property propertyname="MULE_CORRELATION_ID" value="custom_cid" doc:name="Set Correlation ID">         <jms:outbound-endpoint exchange-pattern="request-response" queue="queueOne" connector-ref="Active_MQ" doc:name="Order Queue Producer">         <logger message="#[payload]" level="INFO" doc:name="Logger">     </logger></jms:outbound-endpoint></set-property></http:listener></flow>     <flow name="Order-Consumer_Flow">         <jms:inbound-endpoint exchange-pattern="request-response" queue="queueOne" connector-ref="Active_MQ" doc:name="Order Queue Consumer">         <set-payload doc:name="Set Payload" value="Hello there">     </set-payload></jms:inbound-endpoint></flow> </mule>

JMS Correlation ID

To set the correlation ID is critical to the request-response exchange pattern. Without this, the pattern will not work. Here is the how we can set the correlation ID:

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1 2	<set-property propertyname="MULE_CORRELATION_ID" value="custom_cid" doc:name="Set Correlation ID"> </set-property>