Here the user should specify MultiplexedJBossCacheRegionFactory as their hibernate.cache.region.factory_class. The MultiplexedJBossCacheRegionFactory shares almost all its code with SharedJBossCacheRegionFactory; the main difference is it constructs a different CacheInstanceManager implementation -- the MultiplexedCacheInstanceManager.

MultiplexedCacheInstanceManager differs from SharedCacheInstanceManager in that it does not directly instantiate a cache. Rather, it creates an instance of org.jboss.cache.CacheManager, providing it with a ChannelFactory and the location of the user-specified cache configuration file. The CacheManager parses the configuration file.

MultiplexedCacheInstanceManager analyzes Hibernate's configuration to determine the name of the desired cache configuration for entities, collections, queries and timestamps. See Section 3.1.5, “The MultiplexedJBossCacheRegionFactory” for details. It then asks its CacheManager to provide each needed cache. In the diagram, two different caches are needed:

Both the "optimistic-entity" configuration and the "timestamps-cache" configuration specify the use of the "udp" JGroups channel configuration, so the CacheManager's ChannelFactory will ensure that they share the underlying JGroups resources.

The way the region factory creates regions is exactly the same as in the single JBoss Cache case; the only difference is the region factory's internal reference to its timestamps cache now points to a different cache object from the entity, collection and query cache references.