[news.eclipse.modeling.gmf] Re: GMF mapping Audit Rules

["Christian W. Damus" <cdamus@xxxxxxxxxxxxx>]

Hi, Achilleas,

You can, in the context of any classifier, use allInstances() to access 
all instances of any other classifier.  So, for example:

  context Class1
  inv:
    Class2.allInstances()->forAll(c2 | self.value1 <> c2.value2)

However, this may be over-constrained.  I see from your sketch of your 
model that Class1 and Class2 are aggregated in a root.  So, you might 
rather do:

  context Root
  inv:
    classes1->product(classes2)->forAll(pair |
        pair.first.value1 <> pair.second.value2)

which would scope the constraint to the context of each individual Root 
element.

HTH,

Christian


Achilleas wrote:
> Hi,
>
> I will like to ask if it is possible to compare two attributes using one 
> audit rule;one constraint.
>
> For instance if i have the following metamodel
>
>      Root (aggregates classes1,classes2)
> Class1(includes EAttribute value1) Class2(includes EAttribute value2)
>
> Usually when a constraint is written it will be of the form:
>
> Domain Element Target: |Class1::EClass
>     Class1.allInstances()->forAll( c1, c2 | c1 <> c2 implies c1.value1 
> <> c2.value1 )
>
>
> What if I want to compare the values of instances of the Class1 with 
> instances of the Class2? Is there a way to define two Domain Element 
> Targets? Could it be done directly from the Root class specifying this 
> as the Domain Element Target?
>
> Thanks,
>
> Achilleas