[news.eclipse.modeling.mdt.uml2.ocl] Using OCL to specify derived Refere

[JG <jguni@xxxxxx>]

Hi all,

I am using Rose/Ecore to model my application models (for the
representation of database metadata). I have a number of a
Associations/EReferences whose members are actually a subset of another
Association. For example, a Schema contains among other things tables
and structured types (which are both subclasses of ModelElement). I have
a "content" reference from schema which can contain both of these (via
the common superclass). But I also want specific references like
"tables" and "structuredTypes" in the Schema class, which only contain
the tables and structured types, respectively.
Of course I could always write my own getters and setters into the
generated code that would use the "content" relationship and filter only
those classes that are needed. But I am hesitant to do so, as this would
mean a lot of effort and would make it more difficult to keep my still
evolving model in sync with the code.
I considered adding annotations and modify the way EMF generates its
code (so that EMF creates the getters and setters for these "derived"
references for me), but when I took a look at the EMF codegen templates
I lost my courage, as they are quite hard to read, and I did not want to
invest effort in modify the EMF 2.2 templates and have to do the
modification again for the next version of EMF that might change these
templates.

My current "solution" is to have these derived references redundantly,
and setting them via a Helper class. For example, I have an
"attachTableToSchema method, which adds the given table both to the
"content" and to the "tables" relationship. This is however, quite
cumbersome and was only intended as a temporary fix.

So to come to the question: I understand that OCL can (or is meant to be
able to?) specify derived attributes. Could this mechanism also be used
to specify a derived relationship (which is usually many-valued).

Regards

Jürgen