On 23 Dec (18:47), Gavin King wrote: > Would someone have a look over this: > > http://carrierwave.sourceforge.net/doc/Overview.html > > and figure out exactly what it does and how it does it .... it has > a Hibernate persistence provider, apparently, and seems to > maybe help with the problem of retrieving a fully initialized > graph of objects. > > I havn't quite got time to try to get my head around it right now.
Ah, I developed something similar to this for my company: An abstract Criteria. We faced the problem of decoupling the client from the Business Facade: A client view needs all Persons whose firstName is "Foo" and wants the returned Collection to be a sorted List by "lastName". Imagine other abstract "queries" or "criterias" like that. The EJB Entity Bean approach would be to model methods and finders for every kind of query. Thats not a solution of course. Our abstract Criteria is an object query parse tree, you just build the Query in memory with method calls like infix/postfix/projection/selection/whereClause/and-much-more This gives you a Criteria object which can be passed down to the Business Facade to retrieve Collections. A method would be defined as "findPersonsByCriteria(Criteria criteria)". The DAO (abstract DAO factory) also receives a Criteria. The magic part is: The Criteria has Generators for, currently: EJB-QL, SQL, HQL. EJB-QL is pretty useless, but it was an easy start. The DAO uses the appropriate Generator to produce the real query for its native implementation, e.g. the HQLGenerator. So far, we used the Criteria on a couple of projects and never wrote any SQL or other queries by hand. I like it. :) CarrierWave has the same idea, but a different implementation and some features our Criteria doesn't have or would be outside the scope (like modification of the graph). -- Christian Bauer [EMAIL PROTECTED] ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ hibernate-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/hibernate-devel
