[Modeling] Feedback on the latest draft interaction diagram s pec.

Stephen Cranefield scranefield@infoscience.otago.ac.nz
Mon, 7 Jul 2003 10:06:44 +1200

Marc-Philippe Huget wrote (in response to my comments on the
last draft of the interaction diagram specification):

> > * There are stereotypes for changing and adding roles.  Why isn't
> >   there one for deleting a role too?
> Er... let's say I consider that a lifeline that has no more 
> messages is
> stopped and as a consequence the role is removed, it is the reason we
> have no stereotype <<delete role>>, do you have any counterexample?

No, you are right.  I was imagining a single lifeline for an agent that
plays different roles, but now I remember that each role an agent plays
must have a different lifeline.

> > * UML 2 allows an abbreviation in the use of combined fragments: more
> >   than one operator can be shown in the corner pentagon of a frame,
> >   e.g. "sd strict" (see page 389 in the UML 2 spec.).  This is useful
> >   because if an interaction has multiple interaction fragments
> >   (representing message ends and nested combined fragments) then the
> >   semantics declare that the weak sequencing operation is used to
> >   combine the sets of traces of the fragments to form the traces of
> >   the overall interaction.  Writing "sd strict" provides a compact way
> >   of getting strict rather than weak sequencing - otherwise the frame
> >   must contain an intermediate combined fragment that uses the
> >   "strict" operator to combine the required message ends, etc.
> I don't understand this point, where do I make an error in the
> specification?

There's no error - I was just pointing out an abbreviation that UML 2
and which we might want to allow in AUML as well.  Here is the wording from
page 371 of the UML 2 spec. that we could consider copying:

  "More than one operator may be shown in the pentagon descriptor.  This is
  shorthand for nesting CombinedFragments.  This means that sd strict in the
  pentagon descriptor is the same as two CombinedFragments nested, the
  outermost with sd and the inner with strict."