Where I work, we use
Java Data Objects, using DataNucleus as the provider. At the outset of my project, I visited Spring in Action, and POJOs in Action, and a couple other books, to try and get up to speed. And oh, yeah, I read the JDO specifications (in shifts--I kept falling asleep!). We settled on JDO because it was 1) more mature then JPA, and 2) it works with our legacy data model with very little work-around. JPA would simply not be able to handle our data model and its old-style relationships without a HUGE amount of coding to manage the relationships.
What I had wanted to do with our app was use Spring as the transaction manager, connection manager, etc. I had two problems, however: JDO is very poorly documented and examples are quite lacking (and we had a short timeline), and I need to retrieve the database URL via a Web server (long story there, the retrieval method isn't going to change, can't have the URL statically configured in a bean, etc.). In JDO, once the PersistenceManagerFactory has been configured, certain properties are immutable. E.g., the DB URL.
So, the problem was, Spring would load the JDO beans and I couldn't set the URL that was retrieved from the Web service. What we ended up doing was creating a custom PersistenceManagerFactory wrapper that loaded all the basic properties, retrieved the URL, and instantiated the Factory. Works OK, I guess, but we would've saved some time in both coding and
testing if we could've just autowired it all together.
My questions for Craig (or anybody who knows) are, does the new book have a more in-depth treatment of JDO and other persistence specifications (e.g., JPA, EJB3). And does Spring 3 provide expanded capabilities for managing JDO providers and resources, over Spring 2? And are those resources any better documented than in Spring 2.x?
I don't want to start any JDO vs. JPA discussions (EJB3 is totally out--not running in a container)--I just want to know if Spring 3 expands JDO-provider management any over Spring 3, and if the book has more in it than the last Spring in Action book I got, which had only a few pages touching JDO.
Thanks,
Matt
