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RE: Why do we have a component model?

From: <paul.downey@bt.com>
Date: Wed, 9 Mar 2005 15:12:15 -0000
Message-ID: <2B7789AAED12954AAD214AEAC13ACCEF1A0333EC@i2km02-ukbr.domain1.systemhost.net>
To: <ryman@ca.ibm.com>, <sanjiva@watson.ibm.com>
Cc: <Anish.Karmarkar@oracle.com>, <bparsia@isr.umd.edu>, <jean-jacques.moreau@crf.canon.fr>, <umit.yalcinalp@sap.com>, <www-ws-desc@w3.org>, <www-ws-desc-request@w3.org>

+1  the Z notation isn't so much another layer of abstraction, but rather
a validation tool for the spec itself.

When Z raises an issue, it's either the consistency of the abstraction or unclear 
text that is at fault. i've far more confidence in Z than the models we're all carrying 
in our heads, certainly the one in mine is very broken.

now it might have been nicer to use OWL, given we're the W3C, and avoid
the difficulties of the Z chars with browsers and pub tools, and maybe 
move the Z to a separate document (problematic), but complaining
about spec issues raised by a QA technique? come on!


-----Original Message-----
From: Arthur Ryman [mailto:ryman@ca.ibm.com]
Sent: 08 March 2005 16:15
To: Sanjiva Weerawarana
Cc: Anish.Karmarkar@oracle.com; bparsia@isr.umd.edu; jean-jacques.moreau@crf.canon.fr; Downey,PS,Paul,XAGA C; umit.yalcinalp@sap.com; www-ws-desc@w3.org; www-ws-desc-request@w3.org
Subject: Re: Why do we have a component model?


I understand your reservations about Z Notation and agree it would be better if the spec didn't need it. However, I think it does. I'd like to clarify the purpose of the Z Notation. 

The WSDL 1.1 was great in that it was short and got the Web services wave going, but it did have some problems. 

My experience as a tool implementer working with WSDL 1.1 pointed out how easy it is for people to misinterpret a spec. We ran into many problems where one team generated WSDL 1.1 that they thought was valid, only to find that other tools could not process it. This was an industry-wide problem. It led to the creation of WS-I. The WS-I BP 1.0 [1] contains around 89 clarifications to the WSDL 1.1 spec. I don't think any of us wants to see that repeated for WSDL 2.0. 

Z Notation is simply a QA technique to expose problems in the spec, and I think it has already found quite a few of them. I am confident that if we produce a spec that has a consistent Z description, then we will have far fewer problems in implementations. 

[1] http://www.ws-i.org/Profiles/BasicProfile-1.0-2004-04-16.html#description 

Arthur Ryman,
Rational Desktop Tools Development

phone: +1-905-413-3077, TL 969-3077
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"Sanjiva Weerawarana" <sanjiva@watson.ibm.com> 
Sent by: www-ws-desc-request@w3.org 
03/08/2005 10:25 AM To<paul.downey@bt.com>, <umit.yalcinalp@sap.com>, <jean-jacques.moreau@crf.canon.fr>, <bparsia@isr.umd.edu> 
cc<Anish.Karmarkar@oracle.com>, <www-ws-desc@w3.org> 
SubjectRe: Why do we have a component model?

Hi Paul,

> seems to me that we spend most of our time trying to fix bugs in the
> model, in particular the area of composition.

Can you back that up with real info please? I'd be impressed if you could
show that we spend most of our time on component model problems. IIRC
very few of our LC comments are about the component model *per se*; of
course they have component model implications as that's how WSDL is

If you want to claim that the Z notation stuff has brought up lots of
well, then the problem is that we decided to retrofit an abstraction on top
an abstraction.. not the other way around. Record will show that I was
doing the Z notation from day one.

>The engineer in me wants to find a
> simpler solution rather than continue to add more sticky tape and chewing

Well so do I. I hardly find this particular assault on the component model a
good reason to throw it all away and start with a new mess.

As was re-asserted at the F2F, the spec as its written was explicitely not
written for end-users (read as people implementing services) but rather for
implementors (read as people implementing WSDL tools/runtimes, SOAP
stacks, etc.). The component model provides a degree of rigour to that; so
read with the runtime and tooling engineer in you rather than the Web
author engineer in you. I know you have at least two engineers in you! ;-)

> i'm drawn to the idea of spec which is focused on the document rather than
> processing model, even if that meant losing import (but keeping a lexical

Been there, done that. Again, with all due respect, you need to read the
archives and see how we got here. I personally was against adding import/
include but lost. Such is the world of design by committee; somethings you
like, some that you don't. The other option is design in a closed room;
you prefer that (esp. if you didn't happen to be in the room)?

Received on Wednesday, 9 March 2005 15:21:54 UTC

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