[Modeling] Re: Seq. diag. answer to Michael Winikoff

James Odell email@jamesodell.com
Wed, 26 Mar 2003 15:52:19 -0500

Radovan makes some good points.  To supplement his comments, I would also
like to add that Sequence Diagrams are not just a UML standard, they are
also the result of the Z.120 standard from the ITU (See SERIES Z: LANGUAGES
description techniques (FDT)  Message Sequence Chart)  So, if we start
deviating (i.e., changing) the "vanilla" sequence diagram, we will be
deviating from *two* existing standards.



P.S.  The ITU (International Telecommunication Union) is the United Nations
Specialized Agency in the field of telecommunications. The ITU
Telecommunication Standardization Sector (ITU-T) is a permanent organ of the
ITU. The ITU-T is responsible for studying technical, operating and tariff
questions and issuing Recommendations on them with a view to standardizing
telecommunications on a worldwide basis.

On 3/26/03 3:29 AM, Radovan Cervenka scribed:

>> On 3/25/03 3:14 AM, Radovan Cervenka scribed:
>>> BTW looking at UML 2.0, I feel that there could be more cases for which
> we
>>> will offer alternative notations. Not only replacing some acronyms by
> icons,
>>> but also replacing maybe several modeling elements by one visual element
> (of
>>> course with unambiguous metamodel mapping). E.g. while modeling some
>>> concept that is naturally represented by a dependency and a constraint.
> It
>>> can be drawn e.g. as a line with special arrowhead and guard, instead of
>>> drawing dependency and constraint as two separate visual elements...
>> At some point, we have to decide how much to *deviate* from UML 2.0 and
> how
>> much to *extend" it.  By "extending" I mean adding to UML 2.0; by
>> "deviating" I mean changing the UML 2.0 notation without extending it.
>> Deviation carries with it the problem that the thousands of people that
> are
>> using it in its non-extended version will not be able to move easily to
> the
>> extended version a minimum of change to the base notation.
> I think that the aim of AUML is to *extend* UML 2.0, e.g. by adding of new
> modeling element types (stereotypes). By default, a standard UML notation
> will be provided for new elements (of course with possible new icons for
> stereotypes, etc.). Furthermore, we can offer *deviations* - PRESENTATION
> OPTIONS. The presentation options can be supported by CASE tools, but they
> do not need to be. Situation is the same also for existing CASE tools and
> UML 1.*. E.g. some tools support special iconic markers for visibility (that
> is a presentation option in UML 1.4) and some support just textual notation;
> or some tools use comma-separated list of template parameters and some tools
> place one parameter per line, etc.
> It is important to realize this "extend/deviate" problem, but at this stage
> of AUML defining it is maybe useless to go into detail "general"
> discussions. We will see concrete cases of notations and presentation
> options, when AUML is defined in more details.
> Regards,
> Rado1.
> --
> Radovan Cervenka | rce@whitestein.com
> Whitestein Technologies | www.whitestein.com
> Panenska 28 | SK-81103 Bratislava | Slovak Republic
> Tel +421(2)5443-5502 | Fax +421(2)5443-5512
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