Issue - 152 - Clarification of usage of "reference-scheme" attribute of "service-ref" element

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Issue - 152 - Clarification of usage of "reference-scheme" attribute of "service-ref" element

Status: open
Categories: Syntax and validation
Date added: 27 Jul 2004
Submitter: Alex Yiu
Date submitted: 26 July 2004
Description: This is a follow-up issue for Issue 34, which we passed to introduce a "bpws:service-ref" element wrapper to contain details of the EPR used by partnerLink. There was some discussion on how to use the "reference-scheme" attribute of the "bpws:service-ref" wrapper element.

Here are some suggested usage:

(A) Keep it required as mentioned in original proposal of Issue 34:

The “bpws:service-ref” has a required attribute called “reference-scheme” to denote the URI of the reference interpretation scheme of service endpoint, which is the child element of bpws:service-ref. Most likely, the URI of reference scheme will have the same value for the namespace URI of the child element of bpws:service-ref. But they are not necessarily the same.

• When the BPEL container fails to interpret the combination of the "reference-scheme" attribute and the content element OR just the content element alone, a standard fault "bpws:UnsupportedReference" must be thrown.

(B) Make it optional:

The “bpws:service-ref” has an optional attribute called “reference-scheme” to to denote the URI of the reference interpretation scheme of service endpoint, which is the child element of bpws:service-ref.

Most likely, the URI of reference scheme and the namespace URI of the child element of bpws:service-ref are not necessarily the same. Typically, this optional attribute is used ONLY when the child element of the “bpws:service-ref” is ambiguous by itself. The optional attribute supplies further information to disambiguate the usage of the content.

Example: different treatments of wsdl:service element

• If that attribute is not specified, use the namespace URI of the content element within the wrapper to determine the reference scheme of service endpoint.

• if the attribute is specified, use the URI as the reference scheme of service endpoint and treat the content element within the wrapper accordingly.
  • When the "reference-scheme" attribute is specified, the URI value is MOST LIKELY different from the namespace URI of the content element for EPR.
• When the BPEL container fails to interpret the combination of the "reference-scheme" attribute and the content element OR just the content element alone, a standard fault "bpws:UnsupportedReference" must be thrown.

Submitter's proposal:

I personally prefer (B) over (A).
Changes: 27 Jul 2004 - new issue

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