Definitions:
concrete use case == use case with a primary actor
abstract use case == use case w/ no primary actor, exists to help other use
cases.
primary actor == an actor that initiates the dialog in the use case.
If you think about it, includes is a dependency from the concrete use case
to the abstract use case because the concrete use case makes no sense
without the abstract one.
Extends is also a dependency in the opposite direction because the concrete
is fine without the abstract, but the abstract extends a concrete so there
is a dependency in that direction instead...
Confusing I'm sure.
--anthony
> -----Original Message-----
> From: Quatrani, Terry [mailto:[EMAIL PROTECTED]]
> Sent: Monday, January 29, 2001 8:15 AM
> To: 'Eric D. Tarkington'; '[EMAIL PROTECTED]'
> Subject: RE: (ROSE) Bar Bet #2
>
>
>
> Eric,
> Glad to help (and you made my day saying that I am your
> favorite writer on
> the UML). I think the reason that they picked a dependency
> relationship is
> that is what is really happening. Use case A depends upon
> Use case B to
> specify some functionality. You are not stating how that
> functionality is
> done, just that it is needed. Does this make sense?
> TQ
>
> Terry Quatrani
> Rose Evangelist
>
> Phone: 610-940-2132
> Cell: 610-659-8272
> Fax: 610-940-2150
>
>
> -----Original Message-----
> From: Eric D. Tarkington [mailto:[EMAIL PROTECTED]]
> Sent: Sunday, January 28, 2001 6:43 PM
> To: Quatrani, Terry; ROSE_FORUM
> Subject: Re: (ROSE) Bar Bet #2
>
>
> Terry,
>
> First of all, I'm thrilled that my favorite writer on the UML actually
> replied to Bar Bet #2. I was just at the point of deciding it was a
> dud, and trying again to stir some controversy. I'm
> forwarding the mail
> to my mother -- see, Ma, somebody important answered me!
>
> Technically, there is one standard (OMG) answer, and the latest Rose
> supports it: we should stop using <<uses>> & <<extends>>,
> and we should
> use <<include>> and <<extend>> with a dependency relationship. The
> discussion probably failed to heat up because people have
> long ago given
> up on using these stereotypes "properly", anyway. I *have* used
> unidirectional association, at least partly because we
> haven't upgraded
> from Rose 98 yet.
>
> The thing that bugs me most is that unidirectional association with
> these stereotypes actually makes more sense to me than dependency.
> Clearly, the base use case will not be "compiled" before
> "linking" with
> the extending use case (because we don't compile use cases,
> at least for
> now). On the other hand, association implies messaging, and
> it seems to
> me that, if you can bundle up behaviour into use cases, the
> bundles can
> send messages to each other.
>
> In the end, standards and common usage will trump other
> considerations.
> I accept that. I've been telling people for years that I
> plan to become
> famous by promulgating "Tarkington's Principle", which says: "It's
> better that it be standard than that it be good." That's a very
> perverse idea to software types, who are nitpicking perfectionists by
> nature, but it's amazing how often it applies. Call it "Tarkington's
> Perverse Principle", if you like. For me, it applies here.
>
> It's quite clear that dependency is the standard relationship to use
> with <<include>> and <<extend>> in use case diagrams, therefore that's
> the better answer until standards change. It still doesn't
> strike me as
> a good answer, though.
>
> I'm looking forward to your next version of Visual Modeling with RR,
> though I don't expect you to explain why dependency is intuitively the
> right relationship in a basic introductory book on the UML.
>
> But, it would be very nice if one of the philosophers or angels at
> Rational Corp. has written this up somewhere. Please, somebody, just
> give me a sense of the word "dependency" that makes sense in this
> context. Bend me, shape me.
>
> -Eric
>
> "Quatrani, Terry" wrote:
> >
> > Eric,
> > Now you can see how hard it is to write a book when things keep
> changing.
> > In the earlier versions of UML (and Rose) the relationships
> between use
> > cases were uses and extends and I think the notation was indeed a
> > generalization arrow. In later (and the current) version
> of UML, the
> words
> > changed to include and extend and the notation was a stereotyped
> dependency.
> > But Rational Rose did not support that (so I used a stereotyped
> > association). Now, Rose does support a stereotyped
> dependency between use
> > cases. So the correct answer is "there are two different
> relationships
> > between use cases. They are include and extend. Both
> relationships are
> > stereotyped dependencies. For an include relationship, the
> dependency
> > points from the use case doing the using to the used use
> case. For an
> > extend relationship, the dependency points from the
> extension use case to
> > the base use case (the use case being extended". These
> relationships will
> > be update in the next version of my book (which I am
> starting to write).
> > Hope this helps.
> > TQ
> >
> > Terry Quatrani
> > Rose Evangelist
> >
> > Phone: 610-940-2132
> > Cell: 610-659-8272
> > Fax: 610-940-2150
> >
> > -----Original Message-----
> > From: Eric D. Tarkington [mailto:[EMAIL PROTECTED]]
> > Sent: Thursday, January 25, 2001 2:24 AM
> > To: ROSE_FORUM
> > Subject: (ROSE) Bar Bet #2
> >
> > It's been months since Bar Bet #1 (which I really enjoyed,
> thanks), but
> > I guess everyone will forgive, since we are all too busy for humans.
> >
> > Largely because I'm teaching the UML at Seneca College (School of
> > Computer Studies), I keep on asking basic questions over
> and over. The
> > instructors don't agree about some basic stuff, and neither does the
> > literature on the UML. We get down to the point where you
> can't appeal
> > to logic and you can't appeal to authority.
> >
> > So, here's my latest vexed question: In use case diagrams, how do
> > association stereotypes know which way to go?
> >
> > In VISUAL MODELING WITH RATIONAL ROSE AND UML, (c)1998, p. 34, Terry
> > Quatrani writes: "Uses and extends relationships must use
> stereotypes
> > because they are both represented by a generalization arrow."
> >
> > In VISUAL MODELING WITH RATIONAL ROSE 2000 AND UML, (c)2000, p. 34,
> > Terry Quatrani writes: "Include and extend relationships must use
> > stereotypes since they are both represented by a dependency
> > relationship." The rest of chapter 3 contains examples that
> > consistently use a unidirectional association relationship, instead.
> >
> > We're teaching an introduction to the UML using Rose, and we've been
> > treating include/extend as identical to uses/extends. So, reading
> > Quatrani, we get three options for which relationship "goes with"
> > include and extend stereotypes:
> > 1. generalization (solid line, closed arrow)
> > 2. dependency (dashed line, open arrow)
> > 3. unidirectional association (solid line, open arrow)
> >
> > Quatrani is a genuinely excellent resource, who gives a lot
> of her kung
> > fu along with the facts in her books. Which one of these options is
> > wrong? Is more than one of them right? Are uses/extends
> the same as
> > include/extend? When David Duchovny comes back, will there
> be another
> > season of X-Files?
> >
> > There are actually two bar bets here. My final formulation is:
> > 1. Uses/extends is the same as the newer include/extend.
> > 2. Unidirectional association is the relationship to which these
> > stereotypes should apply.
> >
> > As before, I won't tell what I think until the pressure becomes
> > unbearable.
> >
> > -Eric
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