IoC container that supports constructor injection with Scala named/default arguments?

Question

I would prefer using constructor injection over JavaBean property injection if I could utilize the named and default arguments feature of Scala 2.8. Any IoC-containers exists that supports that or could be easily extended to do so? (The required information is there on runtime in the scala.reflect.ScalaSignature annotation of the class.)

I also have some basic(?) expectations from the IoC container:

• Auto-wiring (by target class/trait or annotation, both one-to-one and one-to-many)
• Explicit injection (explicit wiring) without much hassle (like Guice is weak there). Like user is injected that way in new ConnectionPool(user="test").
• Life-cycle callback for cleanup on shutdown (in the proper order)

Spring can do these, obviosuly, but it doesn't support named parameters. I have considered using FactoryBean-s to bridge Scala and Spring, but that would mean too much hassle (boilerplate or code generation), as far as I see.

Answer 1

PART A

I have a work-in-progress reflection library that parses the Scala signature and is currently able to resolve named parameters: https://github.com/scalaj/scalaj-reflect

Unfortunately, I haven't yet tied it back into Java reflection to be able to invoke methods, nor have I added the logic to resolve default values (though this should be trivial). Both features are very high on my to-do list :)

This isn't an IoC container per-se, but it's a pre-requisite for another project of mine: https://github.com/scalaj/scalaj-spring. Work on scalaj-spring stopped when it became blindingly obvious that I wouldn't be able to make any worthwhile further progress until I had signature-based reflection in place.

PART B

All of that stuff is intended for big enterprisey people anyway. Those with no choice but to integrate their shiny new Scala code into some hulking legacy system... If that's not your use case, then you can just do Scala DI directly inside Scala.

There's DI support provided under the Lift banner: http://www.assembla.com/wiki/show/liftweb/Dependency_Injection

You should also hunt around for references to the cake pattern