[news.eclipse.tools.emf] Re: EReference and primitive types

[Adrian Herscu <bmf1972@xxxxxxxxxxx>]

Hi Dirk, and thanks for your fast reply :)

Dirk Hoffmann wrote:
> Hi Adrian,
>
> what I would do is to describe types with a type hierarchy like so:
>
> AbstractType<>--0..* Field
>
> AbstractType <|--+- PrimitiveType
>                  |
>                  '- ComplexType
>
> You may extend PrimitiveType further with Integer, String, etc. This has 
> the advantage that you specify the available primitive types in your 
> meta model.

Unfortunately, this requires the user to define the primitive types in 
his model instance.

> You may alternativly define an enumeration attribute with PrimitiveType. 
> Then you would need to add an EEnum with the respective constants.
>
> You may also add an attribute of type java.lang.class to AbstractType.
>
> It really depends on your application on what approach fits best.
>
> Anyway you need to provide some code that creates the PrimitiveType 
> instances I believe. You may use reflection mechanisms to find them if 
> you used the "extend PrimitiveType" approach.

The solution I have found is to make Field abstract and extend it with a 
Reference (that is associated with a Type) and with an Attribute (that 
has "type" attribute with a Primitive EType, where "Primitive" is 
defined as an EEnum enumerating the available primitives).

> Regards,
> Dirk
>
>
>
> Adrian Herscu schrieb:
> > Hi all,
> >
> > I am trying to build a meta-model which describes an application that 
> > contains types, which contain fields.
> >
> > Application <>--0..* Type
> > Type <>--0..* Field
> >
> > Type has a name attribute. Field has a name attribute too.
> > Field also has a type reference (EReference). In the instance the 
> > reference should be of an existing Type.
> >
> > So far so good. But how to add primitive types to the system without 
> > requiring the user to define them as "Type"-s?
> >
> > My current solution is to add an enumerated "kind" attribute to the 
> > Field. Any better ideas?
> >
> > Adrian.