Hibernate3 is now ready for a public test, go get it! It has all (well almost all) features we'll ever need for object/relational mapping, and if it doesn't have it, it's easy to subclass, extend, and implement.
There's been a certain amount of noise recently surrounding simple JDBC frameworks
like iBATIS. I've liked the idea of iBATIS myself, for use in applications which
don't need an object-oriented domain model, and don't work with deep graphs of
associated entities in a single transaction. A JDBC framework also makes good sense
if you are working with some kind of
insane legacy database; ORM solutions tend
to assume that associations are represented as nice clean foreign keys with proper
referential integrity constraints (Hibernate3 much less so than Hibernate 2.x).
Another major change in Hibernate3 is the evolution to use an event and listener paradigm as its core processing model. This allows very fine-grained hooks into Hibernate internal processing in response to external, application initiated requests. It even allows customization or complete over-riding of how Hibernate reacts to these requests. It really serves as an expansion of what Hibernate tried to acheive though the earlier Interceptor, Lifecycle, and Validatable interafaces.
Hibernate3 adds the ability to pre-define filter criteria and attach those filters at both a class and a collection level. What's a
pre-defined filter criteria? Well, it's the ability to define a limit clause very similiar to the existing
where attribute available on the class and various collection elements. Except these filter conditions can be parameterized! The application can then make the decision at runtime whether given filters should be enabled and what their parameter values should be.
I've seen three or four
ORM tool comparisons in the last three weeks; on some weblogs, on our
forum and I've even been part in several decisions.
I just released 2.1.2 . This is a maintenence release, meaning no especially exciting new features (the interesting work is all going on in the 2.2 branch). However there are some small changes that might make a big performance difference in certain specific cases, especially if you are using a second-level cache. I'm hoping that this release brings the 2.1 branch to the same level of maturity that we were able to achieve with 2.0.3.