Part 25, UML and BAG or LIST

[Bernd G. Wenzel]

Dave,

about a year ago, there was a discussion between the ISO 19103
team (including myself) with OMG's UML gurus. The consensus there
was, that the word set is used in its common sense, not its
mathematical sense in the UML spec. In other words, a UML set is
a collection, where duplicates are allowed.

Another recommendation was to use tagged values to express
optionality and uniqueness. This is however only useful in the
case of a UML profile.

:-) Bernd

----- Original Message -----
From: David Price <dmprice at us.ibm.com>
To: <wg10 at steptools.com>; <xmlsc4 at nist.gov>; <wg11 at smiling.net>
Cc: Stephen Brodsky <sbrodsky at us.ibm.com>
Sent: Monday, March 12, 2001 6:06 PM
Subject: Part 25, UML and BAG or LIST


>
> Folks,
>
> I've read the UML sections on Association and Attribute several
times now
> and it's become clear to me that UML has no concept capable of
supporting
> the EXPRESS concept of BAG or LIST with duplicates.  In every
case, the UML
> spec uses the word "set".
>
> Here's the relevent UML 1.3 text:
>
> UML Association
>
> "The Association represents a set of connections among
instances of the Classifiers. An instance of an Association is a
> Link, which is a tuple of Instances drawn from the
corresponding Classifiers."
>
> UML Attribute (multiplicity)
>
> "The possible number of data values for the attribute that may
be held by an instance. The cardinality of the set of values is
an
> implicit part of the attribute. In the common case in which the
multiplicity is 1..1, then the attribute is a scalar (i.e., it
holds
> exactly one value)."
>
>  I'm at a loss as to what to do.  It seems to me that whatever
we do is
> going to violate UML. Perhaps we should chose the option that
makes that
> violation visible? That could mean we'd need to make sure
something in the
> UML gets named Bag-xxx. Anyone have any bright ideas?
>
> Thanks,
> David
>
> IBM Corporation
> 5300 International Blvd.
> N. Charleston, SC 29418, USA
> dmprice at us.ibm.com
> Phone : +1 (843) 760-4341   Fax : +1 (843) 760-3349
> Oooo.
> (UNC)
>  ) /
> (*/
>