Re: How to force initialization of inner objects?

I want to discover dynamically the name and description of specific inner fields declared in a "Component" class but with as little extra effort as possible from the programmer perspective. With:

trait ComponentVar {
  def description:String
}

abstract class Whatever

class MyComponent extends Component {
   object x extends Whatever {
       def description = "Hello, I'm a variable used to do this cool thing in MyComponent"
   }
}

"x" and his description are registered automatically to the local store in the parent "Component" class (e.g. a map) because they extend ComponentVar and the compiler can check that the description is not missing. At the time using "object" seemed easy but I didn't expect it would turn out to be lazy too...

What bothers me most with my approach is that I need to create instance of MyComponent because I cannot access the description string statically. Ideally I would need something like ComponentVar["Hello, this is a description of ComponentVar in MyComponent"] to reason on the type itself but this is not possible with Scala generics.

Any suggestion is welcome,
Sébastien

2008/12/19 Seth Tisue <seth@tisue.net>

>>>>> "Sebastien" == Sebastien Bocq <sebastien.bocq@gmail.com> writes:

 Sebastien> Thanks you all for the advice, it works now. javap shows
 Sebastien> that the field corresponding to the inner object is
 Sebastien> initialized with a new instance of Funny$name in the name()
 Sebastien> method is invoked. Therefore I used reflection to invoke all
 Sebastien> the methods that return a specific type inherited by my
 Sebastien> inner objects like in the sample below.

Now I'm kind of curious what problem you had, that you decided you had
no choice but to do this...?  The whole thing seems baroque and best
avoided if there's some way to avoid it.

--
Seth Tisue / http://tisue.net
lead developer, NetLogo: http://ccl.northwestern.edu/netlogo/

>>>>> "Sebastien" == Sebastien Bocq <sebastien.bocq@gmail.com> writes:

 Sebastien> Thanks you all for the advice, it works now. javap shows
 Sebastien> that the field corresponding to the inner object is
 Sebastien> initialized with a new instance of Funny$name in the name()
 Sebastien> method is invoked. Therefore I used reflection to invoke all
 Sebastien> the methods that return a specific type inherited by my
 Sebastien> inner objects like in the sample below.

Now I'm kind of curious what problem you had, that you decided you had
no choice but to do this...?  The whole thing seems baroque and best
avoided if there's some way to avoid it.

--
Seth Tisue / http://tisue.net
lead developer, NetLogo: http://ccl.northwestern.edu/netlogo/

It still seems to me that you're describing a solution you've already
chosen, rather than describing the problem you're trying to solve.