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

James Odell email@jamesodell.com
Sun, 23 Mar 2003 09:06:51 -0500

Here's a response to another of Michael Winikoff's questions:

>Page 8 (and elsewhere): the threads of interaction of AUML (version 1) are no
>longer used. I'm still getting used to this but I think it's an improvement
>since lifelines are no longer split - except for splitting boxes the vertical
>dimension really does now indicate time, whereas in AUML version 1 it was more
>confusing because of implicit splitting of lifelines.

If I understand your point correctly, UML2 does still support this.  They
are called "activation" bars.  Unfortunately, none of the examples in the
UML 2.0 Interactions chapter depict this, except one.  But, they are still

>page 12, second para: why are Seq, Strict, Critical region etc. not applicable?

After spending a few hours with the author of the chapter, I understand why
they are there.  IMO, some aspects of them are not well defined.  But, we
can choose a) to fix them up, or b) ignore them.  Electrical engineers seem
to want them.