[hibernate-dev] Defaultable service strategies

[Steve Ebersole]

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.