[news.eclipse.modeling.gmf] Re: links aren't drawn correctly

["Steven Kelly" <stevek@xxxxxxxxxxxx>]

The root problem is simply that GMF uses EMF's Ecore concepts for describing 
the modeling languages. Those concepts aren't enough to describe common 
situations nicely - like in the case you describe. This problem was proved 
over 20 years ago, along with the fact that even type inheritance is no real 
solution: see sections 3.5.2 and 4.4 in the article here: 
http://www.dsmforum.org/papers/CASE_Repository.html.

To be able to nicely describe connections that can occur between sets of 
object types, you need a better set of concepts, like the OPRR described in 
that article. With OPRR, you'd just say your connection can be from 
{NodeType1, NodeType2 or NodeType3} to {NodeType1, NodeType2 or NodeType3} 
(or whatever other rule you want).

Maybe the committers can tell us if there are any plans to improve GMF to 
start using more powerful concepts, as other tools have successfully been 
doing for decades?

All the best,
Steve
-- 
Steven Kelly, CTO, MetaCase
www.metacase.com/blogs/stevek

"Alexandr Zaitsev" <zaicev.alex@xxxxxxxxx> wrote in message 
news:7474ff96a760c180b11ab52685b11d3b$1@xxxxxxxxxxxxxxxxxx
> Hello,
>
> I have some figures of different types and I like to connect them with one 
> ConnectionLine. I read in other posts it is possible. I create pairs of 
> sources and targets for each figure in link element, something like this:
> link{
> sourceNode1:Node1Type;
> targetNode1:Node1Type;
> sourceNode2:Node2Type;
> targetNode2:Node2Type;
> sourceNode3:Node3Type;
> targetNode3:Node3Type;
> }
> And I create pairs of LinkMappings, like this:
> linkMapping{
> source:link.sourceNode1;
> target:link.targetNode2;
> }
> linkMapping{
> source:link.sourceNode1;
> target:link.targetNode3;
> }
> linkMapping{
> source:link.sourceNode2;
> target:link.targetNode3;
> }
> linkMapping{
> source:link.sourceNode2;
> target:link.targetNode1;
> }
> and so on.
> For each mapping I specify the same tool creation and diagram link.
> When I try to create link all works good for first link mapping, but for 
> others only record in model file is created but graphical line isn't 
> drawn. In *CanonicalEditPolicy I see that linkDescriptors containes all 
> created links but in domain2NotationMap only one - for first mapping, 
> because in model only one link loaded correctly, others doesn't contain 
> source or target. Why it happens?
>