Issue - 294 - Factoring of XML Schema Artifacts

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Issue - 294 - Factoring of XML Schema Artifacts

Status: received
Date added: 4 Jun 2006
Date submitted: 02 June 2006
Submitter: Dieter Koenig
Document: WS-BPEL 2.0 XML Schema
Description: According to the resolution of issue 24, there will be two WS-BPEL 2.0 XML schema artifacts, each with its own target namespace, one for Executable Processes and one for Abstract Processes.

There are several problems associated with this approach:

1. The XML schema types and elements for Properties and Property Aliases appear currently in the Executable Process namespace. It is *unclear* whether they should also be in the Abstract Process namespace as well. If they are, then it is *unclear* which one to use in the WSDL.

2. The XML schema types and elements for Service References would similarly appear in both namespaces - it is *unacceptable* that the namespace changes when switching between Abstract and Executable - if this schema type would appear on a WSDL operation then this switch would cause a change of the interface.

3. For XPath extension functions defined by WS-BPEL, we again have the same situation: is is unclear whether both namespaces would be used to qualify them - again, it is *unacceptable* that the namespace changes when switching between Abstract and Executable.

4. The XML schema contains many global element definitions instead of just <process> - it is therefore allowed to create valid documents that only contain a <property> element (or a <copy> element, etc.), which is useless and not mandated by the WS-BPEL 2.0 specification.

Submitter's proposal: [Just one option - subject to discussion] Refactor the WS-BPEL 2.0 XML schema artifacts into the following:

1. One WS-BPEL 2.0 XML schema for validation of Executable Processes - the only allowed root element is <executable:process>
2. One WS-BPEL 2.0 XML schema for validation of Abstract Processes - the only allowed root element is <abstract:process>
3. One WS-BPEL 2.0 WSDL extension XML schema for validation of Properties and Property Aliases - same target namespace as (a) - the only allowed root elements are <bpel:property> and <bpel:propertyAlias>
4. One WS-BPEL 2.0 XML schema for Service Reference variable declaration in Executable or Abstract Processes - same target namespace as (a) - the only allowed root element is <bpel:service-ref>

Notes:

• The target namespace values for (a) and (b) are valid URLs that point to the location of the two artifacts, respectively.
• The location of (c) and (d) is provided in a <xsd:documentation> element contained in (a) and (b).
• The XML schema artifact (c) has an <xsd:include> for the schema (a) in order to be able to reuse the WS-BPEL extensibility mechanism.

Changes: 4 Jun 2006 - new issue

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