[Springframework-developer] Abstract bean definitions

[<jue...@we...>]

Rod, Colin, everybody,

I've implemented an "abstract" attribute for <bean> tags in XML bean =
definitions. It works as expected in test cases. I've also adapted the =
"baseTxProxy" bean definitions in Petclinic and JPetStore (as introduced =
by Colin) accordingly, marking them as "abstract" rather than =
"lazy-init".

There's one issue with visibility, though: For consistency, an abstract =
bean definition is currently visible just like any other bean =
definition: returned by ListableBeanFactory's getBeanDefinitionNames and =
ConfigurableBeanFactory's getBeanDefinition. On getBean, an =
BeanIsAbstractException gets thrown.

We plan to introduce a "public" attribute for Spring 1.2: This could be =
used to make a bean private, be it abstract or not. IMO, these are =
effectively two separate concerns: I believe that we should treat them =
separately, i.e. not automatically make an abstract bean private.

For example, a bean factory needs to be able to access a parent bean =
definition in an ancestor bean factory, even if that parent bean is =
marked as "abstract" to never get instantiated directly. If an abstract =
parent bean definition were automatically private, this wouldn't work.

What do you think? I'll polish and commit my current implementation =
tonight, if there are no objections. As I said earlier, I'd like to =
release 1.1 final by the end of this week: Abstract bean definitions is =
the last essential feature for that release.

Juergen