This video gives a brief overview of JMS backchannel and provides example implementation of JMS backchannel using JMS Request-Response endpoints and Request-Reply message processors

1. Implementing JMS
backchannel
Prepared By: Rupesh Sinha

2. Overview
• What is JMS backchannel?
• Implementing JMS backchannel using request-
response JMS outbound and inbound endpoints
• Implementing JMS backchannel using request-reply
message processor
• Testing and observations
• Request-response Vs Request-reply approach
• Conclusion

3. What is JMS backchannel?
− Java Messaging Service are used mostly for
asynchronous communication between client and
server. Mule ESB allows using JMS for synchronous
communication where client and server can be
decoupled completely.
− JMS synchronous communication is also referred
to as “Backchannel”.
− JMS backchannel is not provided automatically by
the JMS protocol or any JMS brokers. Backchannel
must be implemented by the applications.

4. Implementing JMS backchannel
• Mule ESB supports two ways to
implement synchronous messaging
between client and server using JMS
− Using request-response JMS outbound and
inbound endpoints
− Using request-reply message processor

5. Active MQ Connector Configuration
 Click on Global Elements tab in your main flow
 Click on Create Button
 Select Active MQ (type Active MQ in the Filter
textbox to easily find Active MQ connector)
 Add Broker URL, User Name & Password
 Click on OK
 A sample screen and XML configuration is shown in
the next slide

7. Implementing backchannel using request-response
JMS outbound and inbound endpoints
 Request-response JMS endpoints internally creates a temporary
response queue for JMS backchannel
 The response is sent to client via the temporary queue
 The response queue is anonymous and Mule automatically sets the
JMS_REPLY_TO property. This property instructs mule where to send
reply message
 The response queue is created for every message exchange and is
destroyed immediately after response is received by the client
 JMSCorrelationId ensures proper sequencing

8. Client Flow

9. Server Flow

10. Implementing backchannel using request-
reply message processor
 JMS outbound and inbound endpoints are nested in
the request-reply message processor
 Sends requests to target queue through JMS
outbound-endpoint
 Receives responses through the JMS inbound-
endpoint
 Both request and response queues are explicitly
specified and are named queues
 JMSCorrelationId ensures proper sequencing

11. Client Flow

12. Server Flow

13. Testing and observations
 Open a browser and hit the below URL
http://localhost:1111/backchannel
 This will invoke the “jmsmessagepublisher” flow and will send a
message to request queue
 “Jmsmessagereceiver” queue will log the request message received
and will return a new message
 “Jmsmessagepublisher” flow will receive the message returned from
the “Jmsmessagereceiver” queue and will log the final response
 The final response will be printed on the browser
 If using request-response JMS endpoints and running in INFO mode, you
will observe the temporary queue and correlation id logged in logs

14. Request-Response Vs Request-Reply
backchannel
 Request-Response is exchange pattern whereas Request-Reply is a message
processor in Mule
 Request-Response based backchannel is useful if message has to be sent and
received on the same queue whereas Request-Reply based backchannel is
useful if you have two different queues for sending and receiving messages
 Request-Response approach creates a temporary queue for synchronous
communication between client and server whereas Request-Reply approach
uses two named queues
 Request-Response approach creates and destroys the temporary queue for
every message exchange and hence consumes additional CPU cycles and
memory compared to Request-Reply based implementation
 Request-Response approach can become a performance and resource
utilization concern

15. For more details, please refer the MuleSoft reference document at below URL
http://www.mulesoft.org/documentation/display/current/JMS+Transport+Reference

16. Thanks for watching