How to Subscribe to Distributed Topic without Message Duplication

This is about very interesting scenario I came across and I think many of you might have also faced the smiliar situation.

Scenario : I have one distributed topic in my Integration scenario, and I am subscribing to that Distributed topic (Clustered Environment ofcourse) with a proxy service (Oracle service Bus 10g) and storing the same message again into another distributed Queue. So whenever message is getting published to the Distributed Topic, Message is stored in both the clusters and as a result I was ending up with two same messages in single Distributed Topic, each message in one cluster. Because of this, my proxy service was getting called twice for the same message and same two messages were getting stored in Distributed Queue.

Well so issue here is duplicate messages in distributed topic, but I guess writing a word "issue" is not correct, because Distributed Topics are made to behave like this. This is what we call expected behaviour. But my requirement was how to remove this duplication from Distributed Topic.

Here is the trick, Create two seperate Topic (Not distributed Topic) and targeting both the clusters one by one. Now we have something called "Local JNDI Name" in Topic. Set the same value for this field for both the topic and refer to this common name while refering to Topic. This will give very much similar functionaliy like Distributed Topic and yeah ofcourse without message duplication.

Limitation : All limitations applied to local JNDI name will be implicit to this solution.

Sun Cluster Data Service for Weblogic Server Guide for Solaris OS 
Oracle Application Server 10g: J2EE Deployment and Administration 

HermesJMS - Installation, Setup & Monitoring JMS Queue, Topic

This blog is specifically for the people who requires real time monitoring of the JMS resoruces and their in & out. This posting is for installation & setup of HermesJMS Tool on windows environment for monitoring Weblogic 9/10g/or higher versions's JMS resources.

From weblogic 9 onwared , bea (now oracle) started providing web UI for monitoring JMS messages but for a single flow of message traveling through many number of JMS resources like topic , queue etc on Web UI is such headache. At this time HermesJMS is very handy tool to monitor and capture all those details.

HermesJMS Installation, Setup & Monitoring Tutorial

HermesJMS is an extensible console helps you communicate with JMS providers making your life lot easier to browse or search queues and topics, copy messages around and removing them. It fully integrates with JNDI letting you discover administered objects stored, create JMS sessions from the connection factories and use any destinations found. Many providers include a plugin that uses the native API to do non-JMS things like getting queue depths (and other statistics) or finding queue and topic names

Supports following providers :

• Active MQ
• Arjuna MQ
• Tibco EMS
• Fiorano MQ
• JBoss MQ
• JORAM
• OpenJMS
• Oracle, Pramati
• SAP
• SeeBeyond ICAN
• SeeBeyond JCAPS
• Sonic MQ
• WebLogic
• JMS
• WebMethods
• WebSphere MQ

Ok so, lets start Setting up HermesJMS
1. To install HermeJMS first download HermesJMS from sourceforge and run "java –jar hermes-installer-1.12.jar” where you have placed your installer jar file. Open and edit /bin/hermes.bat or hermes.sh. Add the path to your WLS JVM at the beginning of the file right after the REM comments

set PATH=C:\bea\jdk160_05\jre\bin
set JAVA_HOME=C:\bea\jdk160_05

Save hermes.bat/hermes.sh whichever is applicable in your case.

OR

1.you can download Latest version of SOAPUI 3.5 and install it on your machine. HermesJMS will be installed with SOAPUI 3.5 automatically and you can start HermesJMS as shown in below screenshot.


Click on the image to enlarge.












After installation of hermesJMS on any of the above way, if you are using jdk1.6 then you also need to modify /bin/hermes.bat file.
Add -Dsun.lang.ClassLoader.allowArraySyntax=true in startup command.


2. On HermesJMS Window select Action menu and select New -> New Session that will display Preferences screen. In bottom of the window select "providers" tab as shown below.


Click on the image to enlarge.





Right click inside the window and select Add Group. And provide the name say Weblogic10g in classpath group name.

3. Expand the Weblogic10g group and add library to the classpath group by right clicking on library.

For weblogic 9.0 you will require to add weblogic.jar file but if you are using weblogic 10g or higher version you will require to create wlfullclient.jar file from utility provided by Weblogic as mentioned in below steps.

• go to C:\bea\wlserver_10.3\server\lib path on command prompt
• execute java -jar wljarbuilder.jar command
• And file will be created with name wlfullclient.jar in current directory.

4. Now go back to session tab and enter the Session name "Weblogic JMS Local"

In plugin name select "Bea Weblogic" and In Connection factory frame select "weblogic10g" and click on Apply button so that it can load required properties which you need to set as shown in below screenshot and after that click on OK.

Click on the image to enlarge.

Note : ProviderURL propery needs to be set to
t3://host:port

Many users found it difficult to setup Hermes for Clustered Environment. So here is a trick, you will require to give here host and port of any of the cluster. Like t3://:host_name_of_any_single_cluster:port_of_that_same_cluster

Note : Sometime you may not get plugin name listed then just click on OK & close the Preferences window and reopen it, it should get displayed.




5. Now in left side window in HermesJMS you should be able to see the session "Weblogic JMS Local". Right click on that session and select "discover". HermesJMS will find out all the JMS resource located in Weblogic server and list it for you as shown in below screenshot.

Click on the image to enlarge.

In this list Select and particular Queue and right click on it and then select "browse". It will display all messages contained withing that queue in right pane of the window. And you can go through the content of messages.