RE: Proposal to Simplify the UML

Proposal to Simplify the UML
  -----Original Message-----
  From: www-ws-arch-request@w3.org [mailto:www-ws-arch-request@w3.org]On
Behalf Of Cutler, Roger (RogerCutler)
  Sent: Thursday, June 12, 2003 6:02 PM
  To: www-ws-arch@w3.org
  Subject: Proposal to Simplify the UML


  In accordance with the expression on the concall today that we should not
incorporate excessive detail into the UML, I would like to propose the
following guidelines (which I am perfectly willing to admit are phrased
loosely):

  1 - Cardinalities should be omitted unless they are really obvious (and
contribute to understanding the sense of what is going on -- often where
there is a "1")  or where they are really non-trivial and we have discussed
and agreed on them (as one hopes will happen with the number of receivers or
paths).

  The tool I use doesn't give me much choice in eliminating some of the "1",
which I agree is redundant. If someone elee wishes to redraw in another tool
to eliminate the "1"s then they are welcome to do that,

  2 - We adopt a convention, for the purposes of this document only and
documented prominently (since it is nonstandard), that "*" means "0 or more
OR 1 or more, we are not specifying which".  When we really know which we
mean and want to make a point of it, we always use "0,.." or "1,..".

  What is not standard? * means 0 or more. This is now counter to the
changes you suggested yestereday (to elimitae 0..*)

  There are two reasons for this.  To avoid:

  1 - Endless fruitless arguments about arcane issues (like whether a
message exists if it has not been read . does a sender exist if he has not
sent . does a . uh, SLAP! . gotta stop .)

  Why is this fruitless. It helps to fully understand what is going on.

  2 - The possibility of people down the line saying things like:
     A:"The WSA DEMANDS that if a spec will allow a FOO it must in all cases
tell you how to have a BAR";
     B:"The WSA DEMANDS that the spec MUST be capable of having a MEAL
without a BARF".

  and the problem with this is?


  Well, maybe in the latter case it's reasonable, but surely you see what
I'm talking about.  Both cases are, in fact, silly if we never really
thought about how FOO's and MEAL's relate to BAR's and BARF's.

  The point of doing this execrise is exactly to consider all such issues.
Its not just about pretty pictures.

  Let's keep the detail down to things we really mean.

  So after we finish this current excercise of modelling soap, we need to
decuide what detail to elimiate for our doc.

  I suggest that cardinalities are imporant and we should be looking to
supress some of the boxes and relationships.