[V.Next] 4178 Declaration of policy domains in policy expressions

We would like to get this issue logged for V.Next.


http://www.w3.org/Bugs/Public/show_bug.cgi?id=4178


        Title

Declaration of policy domains in policy expressions


        Description and Justification

An explicit declaration of policy domain is important and improves 
processing efficiency. Such an explicit declaration could:

   1. Make explicit requirements on intersection and merging.
   2. Allow the policy vocabulary to be explicitly declared thus
      alleviating the need to iterate through all assertions contained
      in the policy.
   3. Enable the association of semantics with the absence of an assertion.
   4. Facilitate reuse by allowing specialized policy engines to process
      policies for a specific domain.
   5. Avoid combinatorial explosion in computing policy intersections
      whereby there must be a way to determine which policies must be
      intersected with others.

Otherwise, all combinations must be attempted. Combinatorial explosion 
may render impossible the effective and efficient computability of 
intersection of large policies.


        Target

WS-Policy Framework V.Next


        Proposal

Of identified options, one solution would be to add a new attribute to 
the Policy element:

/wsp:Policy/@Domains where @Domains could take a list of URIs to 
indicate the domains that the policy addresses. The URIs are separated 
by a space similar to the PolicyURI attribute. The domains would define 
suitable URIs such as the default namespace.

An example of an RM policy with its domain:

<wsp:Policy wsu:Id="anRMPolicy"
            Domains="http://schemas.xmlsoap.org/ws/2005/02/rm/policy"
            xmlns:wsp="http://schemas.xmlsoap.org/ws/2004/09/policy"
            xmlns:wsrm="http://schemas.xmlsoap.org/ws/2005/02/rm/policy"/>
  <wsrm:RMAssertion/>
</wsp:Policy>

The intersection of policies that address different domains is an empty 
policy. Policies can be merged by adding up the URIs of the respective 
Domains attributes and applying the regular policy merge algorithm. 
Nested policies MAY use the Domains attribute to declare the domains 
they address. The top-level policy element SHOULD enumerate all Domains 
that its nested policies are declaring in their respective Domains 
attribute.


-- 
Fabian Ritzmann
Sun Microsystems, Inc.
Stella Business Park             Phone +358-9-525 562 96
Lars Sonckin kaari 12            Fax   +358-9-525 562 52
02600 Espoo                      Email Fabian.Ritzmann@Sun.COM
Finland