RE: [wsbpel] Issue - 152 - Proposal to Vote

["Martin Chapman" <martin.chapman@oracle.com>]

It is indeed possible to not have the reference-scheme attribute and 
have the scheme be recognized from the QName of the child element of the

wrapper element. For example, a WS-Addressing wsa:EndpointReference 
could be the child element of the wrapper element, and it would be very 
clear from the wsa:EndpointReference element as to which addressing 
scheme is being used. But this is not always the case as explained 
below. Therefore, it makes sense to have the reference-scheme attribute 
and make it optional.

WS-MD uses the WSDL 1.1 service element to reference a Web service by 
adding certain restrictions to the wsdl11:service element -- all port 
child elements of the service element MUST be alternate ways to get to 
the same Web service. This restriction is over and above of WSDL 1.1 
allows/requires. It is certainly possible for someone to use WSDL 1.1 
service element to reference a Web service but not have the restriction 
imposed by WS-MD. Since the same QName will be used as the child element

of the addressing wrapper element (i.e., wsdl11:service), without a 
reference-scheme disambiguator it will not be clear as to which 
addressing scheme is being used.

Martin.

>-----Original Message-----
>From: Ron Ten-Hove [mailto:Ronald.Ten-Hove@Sun.COM] 
>Sent: 27 August 2004 23:52
>To: ygoland@bea.com
>Cc: Martin Chapman; Alex Yiu; Francisco Curbera; 
>wsbpel@lists.oasis-open.org
>Subject: Re: [wsbpel] Issue - 152 - Proposal to Vote
>
>
>Yaron,
>
>Yaron Y. Goland wrote:
>
>> Since service-ref is an attribute how can reference-scheme be an
>> attribute of service-ref? Attributes in XML cannot have attributes.
>
>This is a typo / misunderstanding; service-ref is an element, with a 
>reference-scheme attribute. Service-ref serves as a "wrapper" for the 
>EPR, so it must be an element.
>
>>
>> Furthermore there can never be an ambiguity about the 
>namespace of the
>> EPR because the EPR root element MUST always declare what its 
>> namespace is, even if it's nothing.
>>
>> So I'm still unclear as to what role the service-ref plays.
>
>The namespace of the enclosed EPR may be insufficient to identify the 
>addressing scheme in use. For instance, WS-MD uses wsdl:endpoint 
>elements for EPRs, and it is conceivable that other addressing schemes 
>may follow the same approach (if only newer versions of WS-MD!).
>
>-Ron
>
>
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