[news.eclipse.tools.emf] Re: Is there a way to extend EFactories?

[paul.fullbright@xxxxxxxxxx (Paul Fullbright)]

Ed,

> It's nice that the schema has a version attribute, but that doesn't help 
> you distinguish which version any particular instance will be using.

It does help actually.  We use a custom content describer that introspects 
the root element, namespace, and version, and then we associate the 
resource with the client objects.  We'd just like to not have to create 
twice the number of client objects (we have rather a lot of objects per 
document).

> It still begs the question how you'd know which to use?

(See above)

> > Is such a thing possible?  
> No.
> > Or is something similar possible?
> No.

Hmm.  Unfortunate.

> >   The encapsulation of object creation is the key here for me.
> Certainly object creation is centralized in XMLHelperImpl's   public 
> EObject createObject(EFactory eFactory, EClassifier type) but without 
> information in the document, it's not clear how that would help.

I'll take a look into this.  Thanks.

> Typically "binary" incompatible schema changes should be associated with 
> a change to the namespace and that of course makes the problem very easy 
> to solve because you'd have a different package and different factory 
> for that.

Talk to Sun.  :)  Though all the schema changes are not incompatible.  
Anything valid under v1 will also be valid under v2 (if my example didn't 
have this, that's my fault.)

Thanks,
Paul