Re: [wsrf] [NEW ISSUE] Constraints on use of schema for resource propertiesdocument

[Ian Robinson <ian_robinson@uk.ibm.com>]

The primary requirement that has to satisfied in order to support the
message exchanges defined in WSRF-RP is that the root element of the RPdoc
and any individual resource properties contained within that RPDoc can be
unambiguously identified by QName. This is always possible with the
constraints described in rules 1, 2, 3 and 4.

As a consequence of rule #1, and the association of the QName as an
attribute of the portType, requesters can reason about the structure of an
RPDoc at design time. This is a requirement of WS-RF that is stated in the
charter; we should not relax this rule.
Rule #4 is required for WS-Resources that provide access to resource
properties (rather than just the RPDoc as a whole). Removing rule #4 would
restricts WSRF-RP to operations on the RPDoc as a whole rather than
individual properties. If the TC considered this acceptable then we would
need to provide text that makes this rule normative but optional (so that
IF a WS-Resource supports access to individual resource properties then its
RPDoc MUST.... etc).

We could consider further relaxation of specific aspects of specific rules
but I do not believe it makes sense to simply "Remove the 5 rules and
substitute a sentence indicating that a resource properties document is
created using XML Schema." for the reasons stated above. I think we would
be better served by an issue that targetted more specific objections and
proposed updates to the individual rules stated in section 4.2.

Regards,
Ian Robinson
STSM, WebSphere Messaging and Transactions Architect
IBM Hursley Lab, UK
ian_robinson@uk.ibm.com


                                                                           
             "Murray, Bryan                                                
             P."                                                           
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             20/08/2005 01:53                                              
                                                                   Subject 
                                       [wsrf] [NEW ISSUE] Constraints on   
                                       use of schema for resource          
                                       properties document                 
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           




Title: Constraints on use of schema for resource properties document

Description:

Section 4.2 of WSRF-RP lists a set of rules that must be followed to
create a resource property document. The rules are as follows:

"
1 The resource properties document MUST be a global element declaration
(GED) in some
  XML namespace. This GED defines the type of the root element of a
resource properties
  document and hence the type of the resource properties document
itself.

2 The resource properties document MUST be uniquely identified by a
QName.

3 The complexType defining the resource properties document MUST define
element children
  only.

4 The complexType defining the resource properties document MUST define
a collection of
  zero or more child elements, called resource property elements. Each
child element MUST
  be a GED.

5 The complexType defining the resource properties document MAY allow
open element
  content (xsd:any).
"

This set of rules prevents an arbitrary XML document from being accessed
through WSRF-RP. Existing resources already having XML representations
may break one of more of these rules, preventing this spec from
accessing those resources.

Rules #1 and #3 are only useful if all access to the representation of
the resource state is through properties. We also have
getResourcePropertyDocument and QueryResourceProperties that allow
non-property access.

Rule #4 is just repeating rule #1.

Rule #5 is not adding anything.


Proposed Resolution:

Remove the 5 rules and substitute a sentence indicating that a resource
properties document is created using XML Schema.