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Re: Can we break Rule One? (was RE: Proposed Draft Charter for Choreo graphy WG)

From: bhaugen <linkage@interaccess.com>
Date: Sun, 10 Nov 2002 06:51:09 -0600
To: www-ws-arch@w3.org
Message-id: <001601c288b7$d7eb25e0$b8eafea9@default>

Mike Champion wrote:
>> As the ISO Open-EDI group discovered (and called Rule One),
>> you're not just exchanging data, you're making legal commitments.
>> For example, Purchase Orders are legal contracts.
>> I expect choreographies (or whatever rules of engagement evolve
>> for electronic business collaborations) to become legal contracts.

> I hope I'm not being naive to think that the business/legal/semantic
> aspects of web services transactions/choreography can be decoupled
from the
> technological aspects of describing sequences of web services and
> coordinating their state.

The business/legal aspects inform the requirements,
if you're trying to coordinate business deals.
Otherwise it doesn't matter.

It's sort of like in eXtreme programming,
the business people define the stories
and decide the priorities, the technical
people devise the solutions (but only
to the stories that were presented,
according to business priority.)

For example, if you define a hypothetical use case
of unnecessary complexity and then create a technological
solution to fit, you may have an over-engineered "solution",
plus you may miss some critical aspects of the problem.
One of which is that complexity hurts in this domain
even more than some others.  And that some
dimensions of complexity hurt more than others.
E.g. the number of parties who must agree
to follow a particular scripted behavior hurts more
than the number of activities.

Or for another example, you may devise a solution
for a stunningly complex set of business interactions
without considering the exceptions, only to find that
a different solution may be much simpler when the
exceptions come into the picture
And many of the exceptions will be business-level,
not technical. (E.g. unfulfilled commitments.)

I think this will end up being the case with
explicit sequencing vs preconditions.
Explicit sequencing will seem simpler
until you get tangled in a spaghetti bowl
of exception paths.

(But I'll wait and see.)

> We discussed this somewhat during the
> requirements phase under "non-repudiation."  That has a business/legal
> meaning that the web services architecture probably won't say much
> but some infrastructure is needed to collect the data about who did
> when, and how we know that reliably, in order to allow business-level
> non-repudiation.  I think we can aspire to something like that in the
> of choreography:

The non-repudiation discussion flailed about similarly
for a while until people who understood the business/legal
aspects of the problem persuaded everybody that
no technical solution exists, all you can do is
collect good evidence.

In other words, the business/legal understanding
helped to simplify the technical issues.

When somebody gets down to collecting the good evidence,
they may want to go back to the business/legal understanding
to help determine what evidence to collect, and in what form.

-Bob Haugen
Received on Sunday, 10 November 2002 08:01:12 UTC

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