Migration web application Listener to cluster mode

[luuzz]

Hello Everybody
We plan to switch our application in a clustered mode in jboss 4.2.0.
We are migrating the web module.
Every time the application is deployed, we have to make some treatments. Right now, we do this using an application listener in the web module.
But if we switch in a clustered mode, each node of the cluster will launch the treatments, what can be dangerous.
We tried to do this using a singleton service. So we created a .sar which we deployed in the deploy-hasingleton folder. But we get NoClassDefFound errors because the service use ejbs which are only deployed later in an Ear file (which is clustered but not singleton).
How can we make the service start after that ear is deployed ?
Excuse my english. Ihope that it's clear enough.
Thanks

[nvijsan]

(1) Use <dependency ....> ?

(2) Can you provide some brief details on what the treatments are?

Thanks
Naga Vijayapuram

[luuzz]

Thank you for the quick answer !!
In our application, when a user connects we create a ActorSession in the data base so that we can know on which machine he's connected to. And while an ActorSession is active (not closed) the user cannot connect on another machine until he closes it by disconnecting himself.
So when the application starts, we have to close all pending sessions other whise the users who were connected, can't connect anymore.
We did this when deploying the .war by using the ContextListener, this solution is not cluster safe.

[brian.stansberry]

See "HASingleton Deployments Using a Barrier" on http://www.jboss.org/community/docs/DOC-9838