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Re: LC 104 and the abstract info model for EPRs

From: Prasad Yendluri <pyendluri@webmethods.com>
Date: Fri, 08 Jul 2005 15:11:05 -0700
Message-ID: <42CEF9F9.4050202@webmethods.com>
To: Jonathan Marsh <jmarsh@microsoft.com>, Anish Karmarkar <Anish.Karmarkar@oracle.com>
CC: "Nilo Mitra (TX/EUS)" <nilo.mitra@ericsson.com>, tom@coastin.com, public-ws-addressing@w3.org
Though I certainly see the merit to the duplication argument, IMO 
Infoset is a formal description of XML representation (it is XML Infoset 
after all). I personally find a conceptual description always useful 
over describing things from strict layout of bits angle only.

Regards, Prasad

------- Original Message --------
Subject: 	RE: LC 104 and the abstract info model for EPRs
Resent-Date: 	Fri, 08 Jul 2005 18:19:28 +0000
Resent-From: 	public-ws-addressing@w3.org
Date: 	Fri, 8 Jul 2005 11:18:33 -0700
From: 	Jonathan Marsh <jmarsh@microsoft.com>
To: 	Nilo Mitra (TX/EUS) <nilo.mitra@ericsson.com>, <tom@coastin.com>, 
Anish Karmarkar <Anish.Karmarkar@oracle.com>
CC: 	<public-ws-addressing@w3.org>


Very interesting work.  It does appear to be simpler on the surface,
especially for the EPR properties (though some slight clarifications in
Section 2 about what the "value" is would be nice - mostly
s/value/EII/).  This works because we can stop talking about properties
altogether.

However, it's not quite so clean in the Message Addressing Properties
section.  We still talk about properties, but conflate the names of
these properties with the elements that represent them, which will lead
to confusion.  I think it's particularly confusing for wsa:RelatesTo.
If I say "the wsa:RelatesTo property has the value 'mid:***'", does that
imply that there is no wsa:Relatesto/@RelationshipType value?  Does
wsa:RelatesTo mean the property or the structure, or is it a structured
property?  I think you've removed some terminology which is designed to
differentiate distinct concepts.  So while it may appear simpler, it
reduces clarity - not a win-win.

It appears to me that adopting just the EPR part of your proposal would
satisfy LC101 and LC104.

-----Original Message-----
From: public-ws-addressing-request@w3.org
[mailto:public-ws-addressing-request@w3.org] On Behalf Of Nilo Mitra
(TX/EUS)
Sent: Thursday, July 07, 2005 10:35 AM
To: tom@coastin.com; Anish Karmarkar
Cc: public-ws-addressing@w3.org
Subject: RE: LC 104 and the abstract info model for EPRs


+1

Nilo 

> -----Original Message-----
> From: public-ws-addressing-request@w3.org 
> [mailto:public-ws-addressing-request@w3.org] On Behalf Of Tom Rutt
> Sent: Thursday, July 07, 2005 1:10 PM
> To: Anish Karmarkar
> Cc: public-ws-addressing@w3.org
> Subject: Re: LC 104 and the abstract info model for EPRs
> 
> 
> Anish Karmarkar wrote:
> 
> > I took an action item to kick off a discussion on LC 104.
> 
> I find this edit to be very readable.
> 
> I prefer this edit to remove abstract properties to the 
> original text.  
> I changes nothing technically.
> 
> Tom Rutt
> Fujitsu
> 
> >
> > Thinking about LC 104 and LC 101, I have the following
> > questions/comments:
> >
> > What is the purpose of section 2.1 [1], the abstract 
> information model 
> > for EPRs?
> >
> > Currently the spec defines an abstract model and then a mapping to 
> > Infoset. Infoset itself being abstract and which can be 
> further mapped 
> > to XML 1.0 or XOP or a binary serialization (eg, IT/UT's ASN.1 based
> > serialization) or something else. This is an XML spec, so it seems 
> > that an Infoset model should be sufficient. I haven't heard of 
> > requirements/usecases for an abstract model for EPRs (for which an 
> > infoset is not sufficient). The abstract properties are in any case 
> > specified in terms of XML schema types. It seems to me that -
> >
> > 1) This unnecessarily complicates and lengthens the spec with no 
> > advantage.
> > 2) This also results in pesky problems such as those 
> pointed by LC 104 
> > and LC 101 -- how does one extend an EPR at the abstract 
> level? At the 
> > infoset level it is clear as there are extensibility 
> > elements/attributes. How are the extensible 
> attributes/elements in the 
> > Infoset (eg: attributes of wsa:EndpointReference element) 
> > reverse-mapped back to the abstract model? Something like
> > /wsa:EndpointReference/@myext:Ext1 attribute has to be 
> mapped to the 
> > abstract model but something like /wsa:EndpointReference/@xml:lang 
> > does not necessarily have to be mapped. How does one distinguish 
> > between the two and what does the spec have to say about this and 
> > about extensibility guidelines and framework.
> > 3) Following the principle: Things should be made as simple as 
> > possible, but no simpler -- it seems to make sense to remove the 
> > abstract model, unless someone can demonstrate a real need for this 
> > (and Infoset is not sufficient).
> >
> > To see what the spec would look like without the abstract 
> model and to 
> > figure out how much work/change is needed, I took the 
> current spec and 
> > removed the abstract model (for both EPRs and MAPs) 
> sections, merged 
> > the still-relevant text from the deleted sections with the infoset 
> > stuff, changed [...] to /wsa:..., + some misc changes to 
> accommodate 
> > the deleted sections (such as removal of text from the 'notation'
> > section). The changed version is attached. I used HtmlDiff 
> to create 
> > diff'ed version (which is also attached). Pl. note that 
> some text was 
> > moved from one section to another, but the diff version 
> just shows a 
> > delete-and-add.
> >
> > Overall, the changes (from an editorial perspective) are 
> minor. Such a 
> > change would also require some very minimal changes in the 
> > SOAP-binding and WSDL-binding specs (to refer to the QNames rather 
> > than [...] properties).
> >
> > Please note that there were some cardinality constraints 
> ('?' and '*') 
> > missing in the infoset mapping for MAP, which I added -- this had 
> > nothing to do with the removal of the abstract model.
> >
> > Comments?
> >
> > -Anish
> > --
> >
> > PS: for those who are worried about 2nd LC, AFAIK, removing 
> a feature 
> > does *not* trigger another LC (but adding a feature may).
> >
> >
> > [1]
> > 
> http://dev.w3.org/cvsweb/~checkout~/2004/ws/addressing/ws-addr-core.ht
> > ml?content-type=text/html;%20charset=utf-8#eprinfomodel
> >
> >
> > 
> ----------------------------------------------------------------------
> > --
> 
> ----------------------------------------------------
> Tom Rutt	email: tom@coastin.com; trutt@us.fujitsu.com
> Tel: +1 732 801 5744          Fax: +1 732 774 5133
> 
Received on Friday, 8 July 2005 22:12:28 GMT

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