[news.eclipse.tools.emf] Re: Finding an CDOObject based on its intrinsic

[Ed Merks <Ed.Merks@xxxxxxxxx>]

Jasper,

Yes, getURIFragment is the most general way of obtaining the string that 
the resource itself decides is the one that it wants to use for 
identifying the object.  EcoreUtil.getID can be used to determine the 
intrinsic ID of an EObject, if it has one, but their's no guarantee that 
any particular resource implementation will necessarily use it.


Jasper wrote:
> Eike,
>
> CDOResource.getURIFragment(EObject) saves the day :-) I guess I should 
> have used this all along (even when using an XMIResource), but I was 
> manually retrieving the intrinsic ID and using just that...
>
> As for the CDOID's, I understand the idea, but as much as possible I 
> want my front-end to be able to work with both CDOResources and 
> XMIResources.
>
> Thanks,
> Jasper.
>
>
> Eike Stepper wrote:
> > Jasper schrieb:
> > > Using an XMIResource, I can look up an object based on its intrinsic 
> > > ID, by calling Resource.getEObject(String uriFragment).
> > >
> > > If I try the same with a CDOResourceImpl, that fails because, as 
> > > I've discovered, CDO uses CDOID's to encode the object's CDOID.Type...
> > Yes, internally CDO always uses CDOIDs to identify objects. They are 
> > guaranteed to be unique ina whole repository (as opposed to only a 
> > resource). You can think of it as an opaque token that is valid only 
> > in the associated session (you even can't compare them between 
> > sessions). You can use it in any view of the session: getObject(CDOID).
> >
> > > Does this mean that CDO does not honor the intrinsic ID's declared 
> > > in the model? Or if it does, how can one find an EObject based on 
> > > the intrinsic ID?
> > I don't think that CDOResource honors *intrinsic* IDs. But if the CDO 
> > native apporach, i.e. CDOView.getObject(CDOID), doesn't suit your 
> > needs there should now (HEAD) be the possibility to call 
> > CDOResource.getURIFragment(EObject) to receive a fragment that you 
> > can use with CDOResource.getEObject(String). The fragment will 
> > possibly not contain the value of the ID attribute of your model but 
> > rather an encoded CDOID.
> >
> > Maybe the URI gurus want to add something?
> >
> > Cheers
> > /Eike