On Thu, Jan 19, 2012 at 8:55 AM, Durchholz, Joachim <joachim.durchh...@hennig-fahrzeugteile.de> wrote: > Delegation would give me more independence from the generated code, at the > expense of some memory usage (which could become relevant since some of the > things we do are bulk operations on hundreds of thousands of objects; some of > the operations haven't been split into reasonably-sized auto-continuing > transactions yet).
It's trivial to change the template to generate delegation patterns instead. I've done that in a project where either Cayenne or JPA could be used as the backend. In fact, I used Cayenne templates to generate both backends. The same project also worked with an in-house system where all of the "authoritative" metadata was stored in a database. I wrote a simple extension to the modeler to automatically "import" from the metadata rather than the xml file, and then resave it to a standard cayenne format. > I'm extremely wary of modifying templates. It means I have to revisit them on > each and every Cayenne update to see whether the basic machinery has changed > and I need to redo my modifications. The templates are standard velocity templates with a very few number of cayenne-specific attributes predefined. I am fairly certain that the templating tasks have only changed once in the last 8 years -- I did the upgrade -- and when they did change, full backward compatibility was left in as an option. I am not using the 3.x branch yet, but I would expect that Cayenne 1.1 templates created back in 2004 would work just as well today. Yes, it's always possible that the basic data structure behind the Cayenne mapping could change, but I don't think that's happened yet, other than perhaps new additions, which shouldn't affect older models.
