Support session replication through OSGi 6 http whiteboard

Currently, session replication can only be done through specifying the Hazelcast filter/listener in the web.xml file of a web-application. This can be a serious disadvantage if you also want to install a web-application to another web-container which does not need clustering, and, consequently, does not contain the Hazelcast libs. In this case, the application won't start.

I suggest an additional way how session replication could be realized without the need of modifying the web-app: it could be done through a Cellar component which implements a http whiteboard. I would realize this as follows:

• Register a Filter/Session listener to the OSGi service registry. Per default, every web-application installed is considered for session replication.
• It should be possible to configure Hazelcast filter properties either through a config file inside the OSGI-INF folder of the web-app, or, through the ConfigAdmin service.
• If the sessions of a specific web-application should not be replicated, then this could be flagged either through a config file inside the OSGI-INF folder of the web-app, or, through the ConfigAdmin service.
• The new Cellar component should be installable as additional feature "http-failover"

What's your opinion?