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RE: [Bug 8205] New: MEX: can mex appear more than once in an EPR

From: Doug Davis <dug@us.ibm.com>
Date: Wed, 20 Jan 2010 07:35:13 -0500
To: public-ws-resource-access@w3.org
Message-ID: <OFA3FC96B9.A7FF47B7-ON852576B0.00681839-852576B1.00452727@us.ibm.com>
To illustrate why this might be needed, take a metadata resource, EPR0, 
that has as its representation a mex:Metadata document:
EPR0.transfer.Get():
     <mex:Metadata attr='foo'> list of <metadataSection>s #0 
</mex:Metadata>

This would appear in an EPR like this:
<wsa:EndpointReference>
  <wsa:Address> ... </wsa:Address>
  <wsa:Metadata>
    <mex:Metadata attr='foo'> list of <metadataSections>s #0 
</mex:Metadata>
  </wsa:Metadata>
</wsa:EndpointReference>

Now change it slightly. Start with a Metadata resource, EPR1,  that has as 
its representation a mex:Metadata document:
EPR1.transfer:Get():
     <mex:Metadata attr='foo1'> list of <metadataSection>s #1 
</mex:Metadata>

Add a 2nd (different) Metadata resource, EPR2,  that is associated with 
(ie. is metadata for) the same service:
EPR2.transfer:Get():
     <mex:Metadata attr='foo2'> list of <metadataSection>s #2 
</mex:Metadata>

These would appear in an EPR for that service like this:
<wsa:EndpointReference>
  <wsa:Address> ... </wsa:Address>
  <wsa:Metadata>
    <mex:Metadata attr='foo1'> list of <metadataSections>s #1 
</mex:Metadata>
    <mex:Metadata attr='foo2'> list of <metadataSections>s #2 
</mex:Metadata>
  </wsa:Metadata>
</wsa:EndpointReference>

If we forced people to merge these two into one mex:Metadata 
element/document then we would lose the ability for someone to extend the 
mex:Metadata element as shown in the above example - what's the value of 
'attr' supposed to be?   And we lose any implicit meaning that might have 
been implied by the grouping that was established - as defined by whoever 
did the grouping.  In short, people should be able to define their 
metadata in whatever form they want.

thanks
-Doug
______________________________________________________
STSM |  Standards Architect  |  IBM Software Group
(919) 254-6905  |  IBM 444-6905  |  dug@us.ibm.com
The more I'm around some people, the more I like my dog.



Ram Jeyaraman <Ram.Jeyaraman@microsoft.com> 
01/19/2010 12:41 PM

To
Doug Davis/Raleigh/IBM@IBMUS, Asir Vedamuthu <asirveda@microsoft.com>
cc
"public-ws-resource-access@w3.org" <public-ws-resource-access@w3.org>
Subject
RE: [Bug 8205] New: MEX: can mex appear more than once in an EPR






It is not clear to me why a service would include more than one 
<mex:metadata> element inside the <wsa:metadata> element, since the 
service could already include multiple <mex:medatasection> elements within 
<mex:metadata>. Using a single <mex:metadata> wrapper provides a simple 
and less-confusing processing model to the client.
 
If the concern is that the xs:any inside the <wsa:metadata> allows using 
more than one <mex:metadata> element, then  the specification could fix 
the problem by explicitly limiting the number of <mex:metadata> element to 
at most one. For example, WS-Transfer limits the content as follow [1].
 
How about [2] that explicitly limits the number of <mex:metadata> elements 
to at most one?
 
[1] http://www.w3.org/2002/ws/ra/edcopies/wst.html#Put
The Put request message MUST be of the following form: 
[Action]
  http://www.w3.org/2009/09/ws-tra/Put
 
[Body]
  <wst:Put Dialect="xs:anyURI"? ...>
    xs:any*
  </wst:Put>
The following describes additional, normative constraints on the outline 
listed above: 
[Body]/wst:Put 
This REQUIRED element MUST have as its first child element, an element 
that comprises the representation of the resource that is to be replaced. 
[2] 
http://www.w3.org/2002/ws/ra/snapshots/20091117/wsmex.html#Metadata-in-Endpoint-References
 
/wsa:EndpointReference/wsa:Metadata/mex:Metadata 
A unique mex:Metadata element appearing as a direct child of the 
wsa:Metadata endpoint reference element. No more than one mex:Metadata 
element MUST be present as a child of the wsa:Metadata endpoint reference 
element.
From: public-ws-resource-access-request@w3.org 
[mailto:public-ws-resource-access-request@w3.org] On Behalf Of Asir 
Vedamuthu
Sent: Tuesday, December 15, 2009 9:03 AM
To: Doug Davis
Cc: public-ws-resource-access@w3.org
Subject: RE: [Bug 8205] New: MEX: can mex appear more than once in an EPR
 
Clarification sounds good.
 
From: Doug Davis [mailto:dug@us.ibm.com] 
Sent: Tuesday, December 15, 2009 5:14 AM
To: Asir Vedamuthu
Cc: public-ws-resource-access@w3.org
Subject: RE: [Bug 8205] New: MEX: can mex appear more than once in an EPR
 

On the contrary, it clarifies whether more than one mex element can appear 
and what it means - which was the point of the issue. 

thanks
-Doug
______________________________________________________
STSM |  Standards Architect  |  IBM Software Group
(919) 254-6905  |  IBM 444-6905  |  dug@us.ibm.com
The more I'm around some people, the more I like my dog. 

Asir Vedamuthu <asirveda@microsoft.com> 
Sent by: public-ws-resource-access-request@w3.org 
12/14/2009 09:52 PM 


To
Doug Davis/Raleigh/IBM@IBMUS, "public-ws-resource-access@w3.org" <
public-ws-resource-access@w3.org> 
cc

Subject
RE: [Bug 8205] New: MEX: can mex appear more than once in an EPR
 








It sounds like that the change proposal does not offer any additional 
value to WS-MetadataExchange users. Suggest that we keep it simple and add 
additional text to tighten the specification to everyone?s satisfaction. 
  
Regards, 
  
Asir S Vedamuthu 
Microsoft Corporation 
  
From: Doug Davis [mailto:dug@us.ibm.com] 
Sent: Monday, December 14, 2009 6:04 PM
To: Asir Vedamuthu
Cc: public-ws-resource-access@w3.org
Subject: RE: [Bug 8205] New: MEX: can mex appear more than once in an EPR 
  

Even without this change multiple mex:MetaData elements can appear since 
the xs:any could be another mex:metadata element. 

There is no difference between: 
<mex:Metadata> 
 <mex:MetadataSection>...data1...</mex:MetadatSection> 
 <mex:MetadataSection>...data2...</mex:MetadatSection> 
</mex:Metadata> 
and 
<mex:Metadata> 
 <mex:MetadataSection>...data1...</mex:MetadatSection> 
</mex:Metadata> 
<mex:Metadata> 
 <mex:MetadataSection>...data2...</mex:MetadatSection> 
</mex:Metadata> 

We don't need to say anything about the relationship because there isn't 
one. 

thanks
-Doug
______________________________________________________
STSM |  Standards Architect  |  IBM Software Group
(919) 254-6905  |  IBM 444-6905  |  dug@us.ibm.com
The more I'm around some people, the more I like my dog. 

Asir Vedamuthu <asirveda@microsoft.com> 
Sent by: public-ws-resource-access-request@w3.org 
12/14/2009 08:26 PM 
 


To
"public-ws-resource-access@w3.org" <public-ws-resource-access@w3.org> 
cc

Subject
RE: [Bug 8205] New: MEX: can mex appear more than once in an EPR

 
 









><mex:Metadata> xs:any* </mex:Metadata>?

As you can see, the intent is once - a unique mex:Metadata element 
appearing as a direct child.

> Change the ? to a * on mex:Metadata and remove the word "unique"

We would like to understand why multiple mex:Metadata elements add value? 
What is the relationship among such multiple elements?

Regards,

Asir S Vedamuthu
Microsoft Corporation

-----Original Message-----
From: public-ws-resource-access-notifications-request@w3.org 
[mailto:public-ws-resource-access-notifications-request@w3.org] On Behalf 
Of bugzilla@wiggum.w3.org
Sent: Thursday, November 05, 2009 9:02 AM
To: public-ws-resource-access-notifications@w3.org
Subject: [Bug 8205] New: MEX: can mex appear more than once in an EPR

http://www.w3.org/Bugs/Public/show_bug.cgi?id=8205

         Summary: MEX: can mex appear more than once in an EPR
         Product: WS-Resource Access
         Version: FPWD
        Platform: PC
      OS/Version: Windows XP
          Status: NEW
        Severity: normal
        Priority: P2
       Component: MetadataExchange
      AssignedTo: public-ws-resource-access-notifications@w3.org
      ReportedBy: dug@us.ibm.com
       QAContact: public-ws-resource-access-notifications@w3.org


We define wsa:Metadata/mex:Metadata as:
--
<wsa:EndpointReference ...>
  <wsa:Address>xs:anyURI</wsa:Address>
  <wsa:ReferenceParameters> xs:any* lt;/wsa:ReferenceParameters> ?
  <wsa:Metadata>
      <mex:Metadata> xs:any* </mex:Metadata>?
      xs:any*
  </wsa:Metadata> ?
  xs:any*
</wsa:EndpointReference>

/wsa:EndpointReference/wsa:Metadata/mex:Metadata
  A unique mex:Metadata element appearing as a direct child of the
wsa:Metadata endpoint reference element. 
--

What not clear is whether or not there can be more than one
mex:Metadata element under the wsa:Metadata element since the xs:any could
technically include it.  I see no reason to ban it.

Proposal:
Change the ? to a * on mex:Metadata and remove the word "unique".

or if we do want to ban it then we need to add some text being explicit 
about
it.


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Received on Wednesday, 20 January 2010 12:36:04 GMT

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