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RE: Are nested assertions part of the policy vocabulary?

From: Ashok Malhotra <ashok.malhotra@oracle.com>
Date: Mon, 16 Apr 2007 14:23:54 -0700
To: "public-ws-policy@w3.org" <public-ws-policy@w3.org>, "public-ws-addressing@w3.org" <public-ws-addressing@w3.org>
Message-ID: <20070416142354172.00000003048@amalhotr-pc>
I'm at the OASIS Symposium and have had extensive discussions with the WS-Addressing folks re. the problems they are having in using WS-Policy to express their requirements.

 

As I see it, the sticky usecase is where the provider wants to say this it supports WS-Addressing in all its manifestations and the requester specifies that it supports a particular variation of WS-Addressing.   These two policies must match.  Thus, the provider says:

 

<Policy>

     <ws-addressing>

         <Policy/>

     </ws-addressing>

</Policy>

 

And the requester says:

 

<Policy>

     <ws-addressing>

         <Policy>

             <ws-addressing-specific-assertions> 

         </Policy>

     </ws-addressing>

</Policy>

 

These two policies must match in the intersection algorithm.  The text that prevents them from matching says:

 

"If either assertion contains a nested policy expression <http://www.w3.org/TR/2007/CR-ws-policy-20070330/#policy_expression> , the two assertions are compatible if they both have a nested policy expression and the alternative in the nested policy expression of one is compatible with the alternative in the nested policy expression of the other."

 

In the note below (which Glen +1ed), Maryann suggests that a Policy with just the <ws-addressing> assertion is expressing a constraint which can be met in several ways - at least that's how I read her note.  She does not, however, suggest concrete wording.  Here are a couple of suggestions:

 

1.	Change the quoted text above to say that matching of nested policy assertions is dependent on the semantics of the parent assertion.  This way, WS-Addressing could define its own semantics for matching and solving their usecase.
2.	Bob Freund suggested a wildcard assertion that could be included within a nested Policy that would match any other nested policy.

All the best, Ashok 

________________________________

From: Maryann Hondo [mailto:mhondo@us.ibm.com] 
Sent: Wednesday, April 04, 2007 7:37 AM
To: Glen Daniels
Cc: Ashok Malhotra; Monica J. Martin; public-ws-policy@w3.org; public-ws-policy-request@w3.org
Subject: RE: Are nested assertions part of the policy vocabulary?

 


Glen, 
I think the problem is that the assertions are really trying to express a constraint .....and should be something 
like "nonAnonymousONLY".  so the absence, is not the absence of support but rather the absence of the constraint. 

And in this case I think the " no constraints" is  sufficient for your use case 
The client has no constraints on what the provider will do. 
That should intersect with all the provider options. 

I hope we can talk this through on the call. 
Maryann 



"Glen Daniels" <gdaniels@progress.com> 
Sent by: public-ws-policy-request@w3.org 

04/04/2007 09:59 AM 

To

"Monica J. Martin" <Monica.Martin@Sun.COM>, "Ashok Malhotra" <ashok.malhotra@oracle.com> 

cc

<public-ws-policy@w3.org> 

Subject

RE: Are nested assertions part of the policy vocabulary?

 

 

 





Hi Monica:

I'm a little confused here.  Are you and MaryAnn indeed saying that
selecting the first alternative in Ashok's (and indeed WS-Addressing's)
example means that neither anonymous nor non-anonymous responses are
allowed?  That certainly isn't the goal of the policy, and indeed this
interpretation would seem to disallow ANY kind of response.

How would you write a consumer policy which was meant to successfully
intersect with endpoint policies which either a) express nothing about
anonymous responses, b) express a requirement for anonymous responses,
or c) express a requirement for non-anonymous responses?

--Glen

> -----Original Message-----
> From: public-ws-policy-request@w3.org 
> [mailto:public-ws-policy-request@w3.org] On Behalf Of Monica J. Martin
> Sent: Tuesday, April 03, 2007 5:30 PM
> To: Ashok Malhotra
> Cc: public-ws-policy@w3.org
> Subject: Re: Are nested assertions part of the policy vocabulary?
> 
> 
> 
> hondo: Ashok,
> My response is yes.
> Maryann
> 
>  >>mm1: Ashok, agree with MaryAnn on question one answer - this point 
> has been made that the nested assertions are part of the policy 
> vocabulary.  Yet, an important point associated with this surrounds 
> whether or not the guiding conformance [1] requires support for those 
> response types - that provides substance on your second 
> question and its 
> disposition.. [2]
> 
> We also state in Section 3.2 Framework before the statement you cite:
> 
>     An alternative with zero assertions indicates no behaviors. An
>     alternative with one or more assertions indicates 
> behaviors implied
>     by those, and only those assertions.
> 
> Remember: (no position just stating the action-result), we augmented 
> this text in 
> http://www.w3.org/Bugs/Public/show_bug.cgi?id=3602 Issue 3602.
> 
> [1] WS-A specification(s) referenced
> [2] Related to empty and the base assumptions of WS-Addressing.
> 
> >Ashok Malhotra wrote: Section 3.2 of Framework says "When an 
> assertion whose type is part of the policy's vocabulary is 
> not included in a policy alternative, the policy alternative 
> without the assertion type indicates that the assertion will 
> not be applied in the context of the attached policy 
> subject."    Are nested assertions included in the policy's 
> vocabulary?
> >
> >Consider the following example:
> >
> >  <wsp:ExactlyOne>
> >        <wsp:All>
> >            <wsam:Addressing> <-- supports all response 
> types --> Alternative 1
> >                <wsp:Policy> 
> >                </wsp:Policy>
> >            </wsam:Addressing>
> >        </wsp:All>
> >        <wsp:All>
> >            <wsam:Addressing> <-- requires Anonymous 
> responses --> Alternative 2
> >                <wsp:Policy>
> >                          <AnonymousResponses />
> >                </wsp:Policy>
> >            </wsam:Addressing>
> >        </wsp:All>
> >        <wsp:All>
> >            <wsam:Addressing> <-  requires nonAnonymous 
> responses --> Alternative 3
> >                <wsp:Policy>
> >                          <NonAnonymousResponses />
> >                </wsp:Policy>
> >            </wsam:Addressing>
> >        </wsp:All>
> >    </wsp:ExactlyOne>
> ></wsp:Policy>
> >
> >If Alternative 1 is selected, does this mean that neither 
> Anonymous responses nor NonAnonymous responses are allowed as 
> both are part of the policy vocabulary but not included in 
> the alternative.
> >
> >All the best, Ashok
> >
> >  
> >
> 
> 
> 
> 
Received on Monday, 16 April 2007 21:24:57 GMT

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