Hello,

I've got a question about integrating Hibernate into the business and data tier within a multi-tier J2EE application.

Tiers:
(1) Presentation
(2) Business
(3) Data

The data tier is encapsulated within DAO's returning DTO'S. A BO within the Business Tier has one or more DTO's associated (I'll call them Business Entities so that they are not confused with the DTO's that are passed to the presentation tier). The Business Entities are the persistent Hibernate Objects. The idea was to seperate the data tier completely from the business tier.

After some lively discussions someone meant that I'm missusing Hibernate as it was intended to persist the Business Objects itself, following the OO paradigma that keeps data and operations together. But what about seperation of concerns? Do I really need to integrate the BO's into the data tier (Which is necessary if I return BO's from the DAO's)?

Are there some good architects out there that can answer my question?

Thx Rene

It all depends on your needs.

Sometimes it is necessary to seperate the layers models, but more often than not it is ok to share the model (mainly to reduce the overhead of having different models for the exact same thing!)

Check out the Hibernate in Action book - it got a chapter about this stuff.