On your question of going from Analysis classes to design classes I thought
I would interject that the approach of trying to take analysis classes and
convert them into design classes is an approach fraught with difficulties.
The traceability of the relationships and transformations that are occurring
is beyond the ability of most projects. In fact there is little work on how
to do this outside of Desmond D'Sousa's work on the Catalysis method. I've
adopted a pragmatic approach where business objects are modeled in the
analysis model and I expect the transformations to be one to one on these
going into design. In addition, I model generic processing objects in the
analysis model that are proto-subsystems. These processing objects may be
combined into subsystems at design time, but not split. Some of these
processing objects fall naturally out of the business domain and some are
architectural constructs. The introduction of architectural constructs into
an analysis model may strike you as odd but I find it is a big positive. It
forces the analysis model and the architecture model to have some
correspondence at a very high level. This helps the architecture evolve
from an abstract stock architecture into a customized one appropriate for
the project. On the analysis side, this helps avoid the analysis team going
off into baseless modeling of responsibilities for processing behavior.
This type of analysis modeling is time consuming, fruitless since this is
largely an architectural issue, and can result in analysis paralysis if not
controlled. This approach is ideal for component based development because
outside of the business object model, all object discussions are postponed
and made into issues to be worked when the subsystem/component design is
begun. Just my $.02
Neal McWhorter
President
McWhorter Technology Management
Business Process Modeling/Enterprise Architecture/Process Mentoring
[EMAIL PROTECTED]
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]]On Behalf Of Williamson, Rusty
> Sent: Friday, December 01, 2000 5:35 PM
> To: 'Charlie Mead'; Williamson, Rusty
> Cc: 'Couball, James'; 'Rose Forum'
> Subject: RE: (ROSE) Use Case Activity Diagram Location...
>
>
>
> Hi Charlie,
>
> Regarding 'Use Case Activity Diagram Location' -- the answer was never in
> doubt in my mind (which is always a sure sign to seek confirmation when it
> comes to UML!!) but our RUP instructor made some statements that confused
> the issue and others in my organization were in danger of setting off in a
> direction I felt was... not the best. You are right in line with my
> thinking on this and so, it seems, is Rational. My rule on the use-case
> model has always been "if its an 'external view' of 'what' the system does
> it goes in the use-case model" (it looks like RUP puts storyboards in the
> analysis model or use-case realization area so this is now kind of an
> exception). Anyway at the end of this email I've included an email from
> Rational support on this and other matters that were being questioned.
>
> Regarding 'blurred... by combining Analysis and Design': I'm
> willing to give
> it a chance. The decision was made to try to follow RUP 'as is'
> as much as
> possible in the elements we use (that is we are forgoing elements we don't
> feel we need). Your question is timely for me as I am at this
> moment trying
> to figure out how to get from 'use-case realization' analysis classes to
> 'design model' design classes. Pretty much I'm just doing the analysis
> model (and story boards) under 'use-case realizations'. Use-case model to
> 'use-case realization' is cleanly represented by a stereotyped
> <<realization>> dependency (as with include/extend, in Rose you use an
> association... unbelievable!) and all of your analysis diagrams go 'under'
> this realization. Now for trace-ability between this and
> 'design' we should
> do the 'many-to-many' analysis class to 'design class or
> subsystem or method
> or whatever' using the trace dependency... but where exactly?
> Anyway, I did
> like the analysis model (although I was really brought up on a different
> approach using CRC) but I think this will serve.
>
> Regards,
> Rusty
> ------------------------------------------------------------
> Rusty Williamson
> > Sr. Systems Architect
> GERS Retail Systems
> http://www.gers.com/
> The Object Workshop
> http://home.san.rr.com/williamson/
> Home Page
> http://www.znet.com/~rusty/
> ------------------------------------------------------------
>
> ------------------------------------------------------------
> >From Rational Support
> ------------------------------------------------------------
> Hi Rusty,
>
> I got the following comments from one of the RUP developers:
>
>
> > ------------------------------
> > Question 1: Regarding the reply from 'one of the Rational University
> > trainers in Europe', he says:
> > >Without claiming this to be the only way to do things I will
> provide my
> > view
> > >of things.
> > Isn't there an 'official' RUP way of doing things? Jacobson, Booch and
> > Rumbaugh's "The Unified Software Development Process" 1999
> Addison-Wesley
> > states this in no uncertain terms.
>
> The RUP is not quite as rigid as the your question makes it sound. For any
> project, there is a range of appropriate solutions and formality
> of process.
> The choice of how formal to be, and what parts of the process to use, is
> driven by risk and specific observed process-related problems. This
> configuration of the process is, in fact, a key benefit of the RUP.
>
> So while RUP does provide a set of best practices, the choice of
> which best
> practices to apply will vary based on the situation. The
> instructor may not
> have made this as clear as it should have been.
>
> > Question 2: Regarding the reply from 'one of the Rational University
> > trainers in Europe', he says:
> > >In the UC-view you can create an activity diagram to describe the
> > >normal flow and the alternative flows...
> > Trying to answer from the view point of the RUP -- are statechart and
> > interaction diagrams still used in this manner? I say 'still'
> due to the
> > following section from Jacobson, Booch and Rumbaugh's "The
> > Unified Software
> > Development Process" 1999 Addison-Wesley, page 159:
> > "
> > Sometimes however, as in complex real-time systems, the use cases
> > may be so
> > complex that it becomes necessary to use a more structured description
> > technique. The interaction between the actors and the use cases may, for
> > example, go through so many states and alternative transitions
> that it is
> > almost impossible to keep a textual use-case description
> > consistent. It may
> > then be useful to use a visual modeling technique to describe the
> > use cases.
> > Such techniques can help the system analyst to better understand the use
> > cases:
> >
> > * UML statechart diagrams can be used to describe the states of the
> > use case and the transitions between those states; see Figure 7. 16.
> > * Activity diagrams can be used to describe the transitions between
> > states in more detail as sequence of actions. Activity diagrams can be
> > described as a generalized form of SDL state transition diagrams
> > [15], which
> > is a well-proven technique used in telecommunications.
> > * Interaction diagrams can be used to describe how an instance of a
> > use case interacts with an instance of an actor. The interaction diagram
> > then shows the use case and the participating actor (or actors).
> > "
>
> This is a correct statement and the RUP needs to be more precise
> in stating
> when and how different diagramming techniques can be applied. The book
> provides a good introduction to how and when these techniques
> could be used.
>
> > Question 3: Regarding the reply from 'one of the Rational University
> > trainers in Europe', he says:
> > >In the UC-view you can create an activity diagram to describe the
> > >normal flow and the alternative flows (partly replacing the
> need for a
> > >textual uc-description)
> > I'm not sure I would ever use an activity diagram (or sequence or
> > interaction diagram) to 'partly replace' the textual uc-description, but
> > rather to explore, workout and display complex use case flows.
> So that I
> > could understand and know that we (the end user and myself) were
> > on the same
> > page with what the system should do under multiple decisions and
> > circumstances. Sending an example would be difficult but I'm sure you
> > encountered these type of use cases. Also the above quote from
> > Jabcobson's
> > book alludes to this.
>
> Agreed.
>
> > Question 4:
> > Please confirm for me (actually for a co-worker) that you would not see
> > analysis classes anywhere the use-case view.
>
> That is correct; analysis classes would not appear in a use case
> view; they
> are related to use case realizations but these are part of the
> logical view.
>
> Best regards,
> Sara
> ===============================
> Sara Lerman
> RUP/RPW/SoDA Technical Support Engineer
> ===============================
> ------------------------------------------------------------
> ------------------------------------------------------------
>
>
> -----Original Message-----
> From: Charlie Mead [mailto:[EMAIL PROTECTED]]
> Sent: Friday, December 01, 2000 7:12 AM
> To: Williamson, Rusty
> Cc: 'Couball, James'; 'Rose Forum'
> Subject: RE: (ROSE) Use Case Activity Diagram Location...
>
>
>
>
>
> It seems to me that the real question is "what is the diagram trying to
> visualize?' -- and when you use an AD (with or without Swim Lanes
> -- I very
> much
> prefer the former) to visualize the flow and interaction between
> Actors and
> the
> System in a Use Case, you are looking at the system "from the outside,"
> which is
> what the UC view is supposed to do....the fact that you've used an AD is
> immaterial...the fact that you've viewed the system from outside is the
> critical
> fact....
>
> On a related subject: I do think that Rational and RUP have
> blurred/confused
> things a bit by combining the Unified Process's view that there are two
> distinct
> workflows -- Analysis and Design -- into one single workflow (Analysis and
> Design).....I have found considerable value in formalizing the Analysis
> workflow
> via UC realizations that are implementation independent and look basically
> like
> Jacobson's Robustness Analsysis stereotypes (and RUP's Analysis classes)
> placed
> in Collaboration (or responsibility-based Sequence) diagrams....the
> advantage of
> going through a round of UC realization a the "concept-not-class" and
> "responsibility-not-operation/message" level is that it
>
> a) helps you discover things about the UC you may have overlooked; and
> b) firmly established a tracability link into the UC realizations at the
> design
> level.
>
> Also, I have found that the ability to produce
> implementation-independent UC
> realizations (vs implementation-specific design-level ones) may
> not lie with
> the
> same person....System Analysts are, in general, much more willing
> to be (at
> least for the moment) blissfully ignorant of implementation details while
> simply
> modeling responsibility-based collaborations between instances of analysis
> model
> concepts rather than design-level classes .....designers, on the
> other hand,
> tend to want to get immediately to the class and message level in the
> realization....the Unified Process argues, I think, very convincinly for
> having
> a UC Realization--Analysis activity which is separate from the UC
> Realization--Design activity.....I wonder if Rational combined the two UP
> Workflows in large part because of their essentially identical tooling
> requirements....but I don't know that.....
>
> In the RUP class I took, the instructor said that Rational believes that
> developers/designers can gather requirements, build Analysis models as
> needed,
> and move to design and that therefore the workflow Analysis and Design
> should be
> considered as a single workflow....maybe that's true....but I've found it
> hard
> to keep good designers at an implementation-independent level for
> too long.
> --
> and also found that their work is made much easier and traceable
> (i.e. their
> implementation-specific compromises much easier to evaluate and
> potentially
> negotiate with customer requimenets) in the presence of formal UC
> Realizations
> at the Analysis level....
>
> charlie
>
>
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