I was also looking for a JPA CacheLoader implementation to be used with OGM as was asked here: viewtopic.php?f=31&t=1012798&start=0
as it seems a powerful combination. However, I do understand that it is not there yet.
So, I decided to take a quick look at what it would take to implement one. Looking at the existing Jdbc implementations I see that some of them extend LockSupportCacheStore which locks the keys before delegating to the concrete subclass. Is that really needed in the context of JDBC (it did make sense in the context of a File store, for instance)? If I were to create a JDBC Cache store, should it extend AbstractCacheStore or LockSupportCacheStore?