| Re: Extending JWT's EMF metamodel [message #26641] |
Wed, 02 July 2008 04:39  |
 Marc Dutoo
Messages: 71
Registered: July 2009 |
Member |
|
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Hi all
Please reply to this message instead so it also get posted in JWT's forum.
Regards,
Marc
Marc Dutoo a écrit :
> Hi all
>
> In the project Eclipse JWT, we manage workflows using ecore-specified
> XMI models and we want to let our users define and add custom
> information in it.
>
> We've logically though about allowing to define ecore metamodels than
> extend ours, and about the possibilities of Dynamic EMF. So we've tried
> a few things (using Europa's EMF) and come across what seem to be
> limitations of extending EMF, especially concerning typing of relations :
>
> * a dynamic class can only extend a non-interface, non-abstract
> static class. OK, actually I can agree with this one ;)
>
> * in order to create dynamic extensions inheriting from this
> non-interface, non-abstract static class, I've had to create and
> register a custom factory that does this work for the package containing
> the dynamic ecore extension. Well, ok again, we could automatically do
> this for all ecores that are found in a given place.
>
> * Now to the fun stuff : I defined in a dynamic EMF extension to my
> core, static metamodel a containment eReference that whose target type
> is a core, static type, but any sample model fails to load. It appears
> that proxy resolution fails for my eReference at parsing : it goes
> through XMLHandler.setFeatureValue()'s proxy handling code at line 2628
> where either createObjectFromFeatureType() believes the eReference's
> eType is eClassifier (because it is the type of the "eType" feature of
> EReference), or createObjectFromTypeName() believes the eReference's
> eType is PropertyImpl (whereas it should be a ClassImpl with name
> Property).
>
> * and upside down, I defined a core, static-typed element under a
> dynamic defined, but was not able to load a sample following this model,
> for the same reason. Though proxy resolution works fine for attributes,
> or if typing the dynamic-defined relation with a dynamic-defined
> extension of a core, static type.
>
> Any feedback about this behaviour ?
>
>
> NB. for those more interested about the "requirements" side of our
> endeavours, you can look here see more here
> http://wiki.eclipse.org/JWT_Metamodel .
>
> Regards,
> Marc Dutoo
> Open Wide
> Eclipse JWT co-lead
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