Generic bounds (super/extends/eUpperBound/eLowerBound) queries

[ewillink]

While rationalizing OCLinEcore support for wildcard template parameters, I spotted that the "? extends MyType" syntax has never been exercised (not used by regular Ecore or UML models or my manual test models).

While trying to elaborate an Ecore test model with wildcards, I found that I could not use the Sample Ecore Model Editor and was puzzled that "extends" relates to eUpperBound and "super" to eLowerBound. I would expect a wildcard to extend its lowerbound. Checking with Wikipedia, the relatres is correct although very confusing to me.

Am I being stupid, or has the eUpperBound/eLowerBound functionality never been used and consequently the inadequacy of the Sample Ecore Model Editor never been detected?

It seems to me that there are three options

• reference to named EClassifier
• reference to named ETypeParameter
• declaration of wildcard EGenericType with bounds

The latter option is missing from the Sample Ecore Model Editor but can be realized by XMI editing.

[merks]

I think you are trying to do something that isn't valid/sensible. You can create upper and lower bounds in this context, i.e., the type arguments of a generic type, but you cannot do that directly for the type of a feature.

E.g., you can do this in Java either:

[ewillink]

Yes. I got confused. A wildcard is only sensible when nested as a specialization argument. Somehow my test example oversimplified to a direct wildcard. The Sample Ecore Model Editor seems fine for sensible cases. Sorry for the noise.