W3C home > Mailing lists > Public > xml-dist-app@w3.org > November 2001

Re: updated proposal on issue #144 - array metadata in SOAP Encod ing

From: Alan Kent <ajk@mds.rmit.edu.au>
Date: Thu, 15 Nov 2001 12:16:12 +1100
To: xml-dist-app@w3.org
Message-ID: <20011115121612.F16396@io.mds.rmit.edu.au>
On Wed, Nov 14, 2001 at 04:31:43PM +0100, Jacek Kopecky wrote:
...
>  All this makes me think we'd best leave this decision on the
> receiver and not try to communicate sparseness on the wire.

There was lots of well thought out discussion about different
interpretations etc that I deleted from the above. This is a
slight side track which I have tried before without convincing
everyone. But I keep coming back to the same conclusion in my mind.

*Personally*, all the complexity, confusion, various interpretations etc
of sparse arrays/partially transmitted arrays/what-is-null-anyway
leads me to the opinion that they should not be in the SOAP spec.
There are so many possible interpretations I would rather push
it up a level. Make SOAP encoded arrays very simple and naive.
Then get groups of people who need sparse arrays agree how to
encode then using an XML Schema specification and make them different
to SOAP encoded arrays. Then each specific interpretation or group
of people who require a specific interpretation can work out how
they want to do the XML markup.

I guess my fundamental uneasiness is that there are so many possible
interpretations that *are* useful in different cases. I would rather
push the argument to the application layer rather than have it in
the low level SOAP layer.

This is why personally I would like to see the SOAP spec drop support
for sparse/partially transmitted/whatever-they-are arrays. Not because
I don't think they are useful concepts, but rather because they are
complex specialist concepts that would be better managed using
XML Schema tuned data structures rather than trying to put into the
fundamental SOAP types. Is using an encoding like below really a problem?
(The markup is only to illustrate using a higher level structure - I am
not trying to propose precise markup).

    <sparsearray>
	<cell><pos>3</pos><value>hello</value></cell>
	<cell><pos>29</pos><value>there</value></cell>
    </sparsearray>

This would be instead of something like

    <sparsearray>
	<item position=3'>hello</item>
	<item position=29'>there</item>
    </sparsearray>

(Both of the above leave out namespaces etc.)

Bottom line: The *length* of the discussions (rather than the content)
leads me to say 'sparse arrays as currently in SOAP are confusing'.
I would also say 'there are many different and useful interpretations.'
I believe moving the concept of sparseness out of SOAP and into a WSDL
file would simplify SOAP without loosing any real power and would increase
interoperability.

Alan
Received on Wednesday, 14 November 2001 20:16:46 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 7 December 2009 10:59:04 GMT