[bpel4people] New Issue: Blocked Substitution Elements in Human TaskDefinitions

[Dieter Koenig1 <dieterkoenig@de.ibm.com>]

Target: ws-humantask.xsd

Description: The WS-HumanTask language
XML Schema contains an abstract element "genericHumanRole" and
substitution elements (such as "potentialOwner" etc.) which are
used in people assignments in place of the abstract element. However, in
a concrete task definition (an XML Schema instance document), the schema
currently does not allow this replacement. The reason is the blockDefault="#all"
attribute on the schema root element. 

Proposal: In general, it is reasonable
to block substitutions and derivations by extension/restriction for WS-HT
language elements. Both languages are already extensible by allowing elements
and attributes of other namespaces to be added to all existing language
elements. It is therefore not necessary to allow introducing substitution
elements or derived types. The same approach is used in bpel4people.xsd
(and in WS-BPEL 2.0 XML Schema artifacts).

In this particular case (genericHumanRole),
it is necessary to allow substitutions in instance documents, otherwise
people assignments cannot be specified at all. This can be done by overriding
the global "blockDefault" setting by using a concrete "block"
attribute. This attribute must allow substitutions, but type derivations
by extension/restriction may still remain blocked. 

As a result, the definition of
the "genericHumanRole" abstract element should be changed from:
<xsd:element
name="genericHumanRole"
type="tGenericHumanRole"
abstract="true"
/>
to:
<xsd:element
name="genericHumanRole"
type="tGenericHumanRole"
abstract="true"
block="extension
restriction"
/>

Kind Regards

Dieter König

Senior Technical Staff Member,
WebSphere Process Server Architect
IBM Software Group, Application
and Integration Middleware Software
WSS Business Process Solutions

Phone:	+49-7031-16-3426	IBM Deutschland
E-Mail:	dieterkoenig@de.ibm.com	Schönaicher Str. 220
		71032 Böblingen
		Germany
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