I'm currently developing a small EJB 3 application for WebSphere AS 7 with WebSphere-MQSeries. It's a very simple app that mainly consists of one MDB listening on a queue, convert the incoming messages and write the extracted data into a db. I've finally got up it and running, but I'm a bit confused regarding ActivationConfig annotations in the code, the ibm-ejb-jar-bnd.xml and the activation spec in WAS itself. My main question is, why do I need ALL of them? Why should/could I specify things like the queue name or destinaton type via annotation (@ActivationConfigProperty) when I still need a activation spec in WAS where I also specify the destination e.g. Queue-Name? I addition I also need a binding via an xml file? Is that right? Is it also possible to specify the activationspec-name via annotation and thus get rid of the xml binding file? Can I avoid creating the activation spec in WAS?
Hope someone can clarify things, thanks.
You cannot avoid the Activation Spec entity because it is responsible to open connection to your JMS provider, query messages according to various options like the message selector filter.
According to WebSphere 7 InfoCenter EJB-3 annotations can replace activation specification properties from binding file but the properties required by WebSphere are not standard.
So as far as I know, you have to provide:
either the binding file, written manually or edited with the deployer tool
either at deployment setting properties in the administrative console or in automated jython/wsadmin script
Be aware that the Activation Spec is a runtime component that can be stopped, typically after some rollbacks on messages. In that case, it no longer consumes message and your MDB has nothing to process until you re-activate it from the WebSphere console.