[Bug 3723] Non-normative recommendation on how effective polices should be calculated when a policy is associated with an arbitrary XML element.

http://www.w3.org/Bugs/Public/show_bug.cgi?id=3723

           Summary: Non-normative recommendation on how effective polices
                    should be calculated when a policy is associated with an
                    arbitrary XML element.
           Product: WS-Policy
           Version: FPWD
          Platform: All
        OS/Version: Windows XP
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Attachment
        AssignedTo: sergey.beryozkin@iona.com
        ReportedBy: sergey.beryozkin@iona.com
         QAContact: public-ws-policy-qa@w3.org
                CC: asirveda@microsoft.com


Title : Non-normative recommendation(or clarification) on how effective polices
should be calculated when a policy is associated with an arbitrary XML element.

Target : WS-Policy Attachment, section 3.3

Justification :
WS-Policy Attachment, section 3.3 [1] describes how a policy can be associated
with an arbititrary XML element. This section says : "The precise semantics of
how element policy is to be processed once discovered is domain-specific;
however, implementations are likely to follow the precedent specified in the
section below on WSDL [WSDL 1.1] and Policy."
The referenced section (see [2] for ex) describes how WSDL element policies are
processed and how they should be merged so that an effective policy for a
corresponding policy subject be calcualted.
This can be generalized in section 3.3 as a non-normative recommendation.

Proposal :
Add to section 3.3 a non-normative recommendation(or clarification) on how
effective polices should be calculated when a policy is associated with an
arbitrary XML element. It can be added after the following text :

"The precise semantics of how element policy is to be processed once discovered
is domain-specific; however, implementations are likely to follow the precedent
specified in the section below on WSDL [WSDL 1.1] and Policy ...".

Like this :

" which follows this non-normative recommendation : When attaching a policy to
an XML element, a policy scope SHOULD be implied for that attachment. The
policy scope SHOULD contain the policy subject associated with that element and
not those associated with the children of that element."
this is a key addition (several options are possible, whichever is
simplier/better):

"An effective policy for a contained policy subject SHOULD be calculated by
merging an element policy of *this* xml element with any other element policies
whose policy scope contains the same policy subject"

If we take WSDL' EndpointPolicySubject [2] as a fictitious example and say we
take a wsdl:port as an arbitray XML element to which a policy is attached, then
according to this non-normataive recommendation an effective policy for
EndpointPolicySubject  will be a merge of wsdl:port, wsdl:binding and
wsdl:portType, which is what [2] describes.

Now, just as an example, let's have a look at an EPR as an arbitrary XML
element with a policy attached inside, perhaps as a first child of epr metadata
element[3]. EPR identifies an EndpointPolicySubject, specifically it might be
assumed it maps to wsdl:port. According to this non-normative recommendation an
effective policy for identified subject will be a merge of a policy attached to
EPR + wsdl:binding + wsdl:portType which is consistent with [2]
Please note that an EPR example is just an example. Relevant sections or
specifications may decide that in case of EPR no merge is needed with
wsdl:portType and wsdl:binding for an effective policy be calculated, that is
its attached policy will be a single element policy which will be used to
calculate an effective policy for a corresponding policy subject

[1]
http://dev.w3.org/cvsweb/~checkout~/2006/ws/policy/ws-policy-attachment.html?content-type=text/html;%20charset=utf-8#XMLElementAttachement 
[2]
http://dev.w3.org/cvsweb/~checkout~/2006/ws/policy/ws-policy-attachment.html?content-type=text/html;%20charset=utf-8#EndpointPolicySubject
[3]
http://lists.w3.org/Archives/Public/public-ws-policy/2006Sep/0028.html

Received on Wednesday, 13 September 2006 17:55:57 UTC