[news.eclipse.modeling.gmf] Re: Shortcut for 1:1:n containment reference

[Alex Shatalin <vano@xxxxxxxxxxx>]

Hello Christian,

> model so that i can ask A for instances of C. (containment, derived,
> transient references from A->C) - Remember: A->B is 1:1 containment
This is a right solution for now with only addition â this reference should 
not be containment and GMF should allow you to specify non-containment reference 
as containment one in ChildReference (you should be able to igronre warning 
on map->gen transformation and generate code then).

> Might it eventually be possible to extend GMF to support this? If so,
I think, generic support of this situation is rather complex, so I doubt 
support this kind of  âcomplex diagram structure modellingâ will be implemented 
in GMF in near future. As you correctly found there is a workaround for this 
problem â you can use EMFâs derived features + java to implement all the 
logic there so for GMF this will be still a parent domain model element (indirectly) 
containing child one.. 
Nevertheless for now you can try modifying GMF templates (using custom templates 
for this diagram editor generation) to handle this situation at least to 
some extend. Once youâll find a solution you can simply raise a bugzilla 
request with appropriate patch attached to contribute this functionality 
into the project.

First of all you have to modify templates generating CreateCommand to properly 
create intermediate element + properly assign child element to the chain 
of containment feature. In this case an entry point will be xpt/diagram/commands/CreateNodeCommand.xpt 
template.

Then youâll probably face some problems with update logic. This part will 
not be so simple (update is quite compex place in GMF) and in this case you 
have to start with xpt/diagram/updater/DiagramUpdater.xpt template. 

I can not remember any other templates to be involved into this task, so 
good luck and ping me if you get any more questions.

-----------------
Alex Shatalin