[hibernate-dev] Defaultable service strategies

Thoughts on allowing certain services to be defaulted to the single implementor registered with the `StrategySelector` service when there is just one? For example, when resolving the RegionFactory unless both (a) `hibernate.cache.region.factory_class` and (b) one of `hibernate.cache.use_second_level_cache` or `hibernate.cache.use_query_cache` are defined caching support will be disabled. What I am proposing would kick in in this case and check to see if there is just a single RegionFactory registered with the StrategySelector and if so use that one. It would allow Hibernate to more seamlessly operate as a JPA provider too, as currently to use caching with JPA and Hibernate users have to do the normal JPA stuff and then also define these Hibernate settings. It would be nicer if they could just do the JPA stuff.