JBC currently does not handle JGroups merge events, mainly because there is no clear way of handling this.

This is clearly not a concern for caches backed with shared cache loaders, but could lead to inconsistencies in other cases. The biggest problem here is that there is no 'correct' way of handling a merge.

The approach proposed is to expose a MergePolicy interface and provide a default implementation (EvictOnMergePolicy?) which evicts the contents of the cache on merge, and allow end users to handle the merge manually.

What, typically, would you need to handle a merge, what should this interface contain?

BTW, this is for 2.1.0 - see http://jira.jboss.com/jira/browse/JBCACHE-471