[GRAAP-WG] XPath issues in Creation Constraints

[Oliver Wäldrich]

Hi Dominic,

In the XMLBeans implementation you can declare the namespace prefix directly
in the Xpath call. The Xpath expression we use are therefore constructed as
follows:

	declare namespace foo='http://bar.org'; $this/foo:bar

I did not find the place in the Xpath specification where the namespace
declaration is defined, but 

  http://www.w3.org/TR/xquery-xpath-parsing/

indicates that this should be standard conform. However, this expressions
work for XMLBeans. I think other implementations should support this as well
(Saxon?).

Best regards,
Oliver

-----Ursprüngliche Nachricht-----
Von: graap-wg-bounces at ogf.org [mailto:graap-wg-bounces at ogf.org] Im Auftrag
von Dominic Battre
Gesendet: Donnerstag, 23. August 2007 00:05
An: GRAAP-WG
Betreff: [GRAAP-WG] XPath issues in Creation Constraints


Hi.

As we are looking for interoperability tests and implementations start
showing up, I have a question about common practice in the evaluation of
creation constraints.

I have raised the issue before, but I think I have never received an answer.

The issue is:

A creation constraint might have an xpath "//wsag:foobar" but it is very
difficult to get the namespace that is bound to the "wsag:" prefix. At least
in case Axis 1 that is used.

Does Axis 2 solve this problem or any other toolkit? Otherwise the question
is whether it is technically feasible to evaluate XPath expressions like
that at all. If it is not feasible, it might be considered a problem in the
WS-Agreement spec.

The reason for my writing this is that I found this bug report:
http://bugzilla.globus.org/globus/show_bug.cgi?id=4227

The Globus Toolkit community faced the same issue and surrendered - or lets
say, they came up with a very nice solution: Introducing a sane query
language TargetedXPath.

This is the Schema:
http://src.gridindex.org/globus_4.1.1/xref/src/wsrf/schema/core/query/

This is the Implementation:
http://src.gridindex.org/globus_4.1.1/xref/src/wsrf/java/core/source/src/org
/globus/wsrf/query/targetedXPath/

I like this approach a lot. Would this be a viable approach for
WS-Agreement?

Best regards,

Dominic
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