Investigate JSR-330 compliance of backstack.lookupService()

[Zhuinden]

https://web.archive.org/web/20110613022418/http://picocontainer.org/inversion-of-control.html

As defined in the PicoContainer docs that no longer exist, "contextualized lookup IoC design" is the Type-0 variant of dependency injection containers, even if lately people call it a service locator.

However this also means that as Backstack in an activity is technically "global context", it is possible to use lookupService on @Inject annotated fields via reflection from outside! Then it stops being a service locator.

So the list to comply to JSR-330 is as follows:

• @Inject support over fields

• @Inject support over setters

• @Inject support over constructor (can I really make that work...? I need to support Provider<T> for that first. Currently you must manually invoke the constructor and create an instance before registering it to the backstack at a given scope. It is only possible to constructor-inject something that is registered as a Provider<T> and not as an instance.)

• Injection of Provider<T> (is there a sane API for that using lookupService(), or is that lookupFactory()? is this really worth it? Not exactly sure if this is worth it. Honestly it's probably not worth it.)

• @Named @Inject (should be easy, service tags are already strings)

Question becomes:

• what of inherited @Inject annotated fields?

• is it enough to support field injection, but not constructor injection + Provider<T>? (did Avalon even support constructor injection + providers? is that even possible with Type-0 DI? it probably didn't, that's why they created PicoContainer in the first place)

• is this worth the effort?

Edge case:

• would I conflict with Dagger?

The idea is cool, though.

[Zhuinden]

YAGNI