Re: A question on OCL



Re: A question on OCL

From: Anthony Simons <A.Simons_at_dcs.shef.ac.uk>
Date: Thu, 18 Dec 2008 10:36:19 +0000
Message-ID: <494A27A3.30400@dcs.shef.ac.uk>
Jorn,

What do you think of my suggestion about subsetting in an *abstract* 
conceptual model?

--Tony

Jorn Guy Suess wrote:
>
> Arnon,
>
>  
>
> As has been advised allInstances() is the technical way to do it. 
> However, there is a formal catch: What is the total set of instances 
> you have? In a technical system (a MOF repository) this set is a 
> closed /extent/. Mathematically, the set is usually infinite. So 
> queries of that are a bit of a high-ball. The more instances you load 
> into a repository, the more drastic these effects become. I assume 
> your question alludes to profiles. You will find that after the third 
> or fourth class drawn into such a Cartesian product, evaluation is 
> quite sluggish.
>
>  
>
> Kind regards,
>
>  
>
> Jrn Guy S
>
>  
>
> *From:* puml-list-request@cs.york.ac.uk 
> [mailto:puml-list-request@cs.york.ac.uk] *On Behalf Of *Arnon Sturm
> *Sent:* Thursday, 18 December 2008 18:36
> *To:* puml-list@cs.york.ac.uk
> *Subject:* A question on OCL
>
>  
>
> All,
>
>  
>
> I wonder whether it is possible to specify an OCL constraint on two or 
> more model elements which do not have a navigation path among them.
>
>  
>
> For example, in case of a library system we have two "unrelated" 
> classes: item and person.
>
> I would like to specify the follwoing constraint: if the items of a 
> particular system are all of type 'journal' or 'proceeding', then all 
> the persons in this system are of type 'faculty'.
>
>  
>
> For sure, there is the possibility to define a "mediator" class that 
> will create navigation paths. However, we are interested in specifying 
> the constraint without that "mediator" class.
>
>  
>
> Thanks for your help,
>
>  
>
> Arnon Sturm
>

-- 
==========================================================================

Dr Anthony J H Simons                   a.simons@dcs.shef.ac.uk
Senior Lecturer in Computer Science     http://www.dcs.shef.ac.uk/~ajhs

Department of Computer Science          tel:  (+44) 114 22 21838
University of Sheffield                 dept: (+44) 114 22 21800
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Received on Thu 18 Dec 2008 - 10:36:24 GMT