Re: [wsrf] Proposed resolution to WSRF 174 - references to instances of MDDs

[David Snelling <David.Snelling@UK.Fujitsu.com>]

Ian,

This sounds very good and I agree. Thanks for the write up.

One question of clarification. This proposal makes no changes to the 
WSDL extension part of the spec and the 
/wsdl:portType/@wsrmd:metadataDescriptor remains a QName. Correct?



On 4 Apr 2006, at 12:26, Ian Robinson wrote:

>
>
>
>
> On the TC call on Mon Apr 3 we discussed an alternative resolution to 
> that
> originally proposed for issue 174 for obtaining the values of metadata
> descriptor document instances that might be specific to a WS-Resource
> instance and potentially dynamic (hence factored as a RP). Instead of
> introducing an additonal RP that contains the value of an RMD instance 
> doc
> for a WS-Resource, this proposal changes the type and some semantics 
> of the
> existing MetadataDescriptorRef RP (which contains a reference to an RMD
> instance doc).
>
> Regardless of which solution we follow, we need to start by fixing a
> problem in theRMD wd-08 draft so that:
>
> Line s 897/898,
>       <xsd:element name="MetadataDescriptor"
>                    type="wsrmd:MetadataDescriptorRef"/>
> should be
>       <xsd:element name="MetadataDescriptorRef"
>                    type="wsrmd:MetadataDescriptorRefType"/>
>
> This resolution then proposes the further change that the definition of
> MetadataDescriptorRefType be changed to wsa:EndpointReferenceType. The
> value of MetadataDescriptorRef is then an EPR to a "metadata 
> WS-Resource"
> associated with the original WS-Resource.
>
> The description of this element should be changed as follosw:
>
> "
> The constraints on this element are as follows:
>
> /wsrmd:MetadataDescriptorRef
> This element is an EndpointReference to a "metadata WS-Resource" 
> associated
> with the target WS-Resource. This metadata WS-Resource has a resource
> properties document that is the MetadataDescriptor document of the 
> target
> WS-Resource. The metadata WS-Resource MUST support the
> wsrf-rpw:GetResourcePropertiesDocument message exchange and MUST 
> respond to
> such a request by returning the MetadataDescriptor document that 
> describes
> the target WS-Resource.
> "
> The description of
> "/wsrmd:MetadataDescriptorRef/@metadataDescriptorLocation" should be
> removed from this section.
>
>
> <TC discussion not intended to be included in the resolution>
>
> In general, if a WS-Resource "A" has an associated metadata WS-Resource
> "mdA" then the resource properties document associated with mdA *is* 
> the
> metadescriptor document associated with A. Information about A's
> (potentially dynamic) instance metadata can then be queried (and
> potentially updated) using normal WSRF-RP message exchanges targeted 
> at the
> mdA EPR.
> A constraint on metadata WS-Resources, above and beyond that of general
> WS-Resources, is that they MUST support the GetResourcePropertyDocument
> message exchange (which is optional for general WS-Resources). The
> constraint needs to be stated in the RMD doc in the section "10.2 Using
> Resoure Property Elements to expose MetadataDescriptors "
>
> </TC discussion not intended to be included in the resolution>
>
>
> The schema should then define:
>     <!--
>     <MetadataDescriptorRef>
>       <wsa:Address>URI</wsa:Address>
>       <tns:SomeReferenceParameter>xsd:any<tns:SomeReferenceParameter> ?
>     </MetadataDescriptorRef>
>     -->
>       <xsd:complexType name="MetadataDescriptorRefType" >
>         <xsd:complexContent>
>           <xsd:extension base="wsa:EndpointReferenceType">
>           </xsd:extension>
>         </xsd:complexContent>
>       </xsd:complexType>
>
>     <xsd:element name="MetadataDescriptorRef"
>                    type="wsrmd:MetadataDescriptorRefType" />
>
>
>
>
>
> Regards,
> Ian Robinson
>
>
-- 

Take care:

     Dr. David Snelling < David . Snelling . UK . Fujitsu . com >
     Fujitsu Laboratories of Europe
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