Issue 278

[Kevin Conner <Kevin.Conner@arjuna.com>]

In response to my AI from the last meeting.

Summary of the issue:

The context schema allows for extension by specifying an XMLSchema any extension at the start of the context type.  This allows for extension elements to prefix the context structure provided their qualifed names are not included in the context namespace.  It is also a requirement for each derived context structure to have its own extension point.

If we are to continue with the use of the XML Schema any at the top level of the context type then we will end up with an ambiguity.  Placing the any at the start of the cf structure causes an ambiguity with the trailing optional elements within context structure, whilst placing it at the end causes an ambiguity with any derived structure.

My suggestion is to encapsulate the extension elements within a top level element, isolating them from all other elements.

The cf context structure would look as follows: -

<xs:complexType name="RegistrationContextType">

  <xs:complexContent>

    <xs:extension base="wsctx:ContextType">

      <xs:sequence>

        <xs:element name="registration-service" type="ref:ServiceRefType"/>

        <xs:element name="sub-protocol" type="xs:anyURI" minOccurs="0" maxOccurs="unbounded"/>

        <xs:element name="participant-service" type="ref:ServiceRefType" minOccurs="0" maxOccurs="unbounded"/>

        <xs:element name="extension" minOccurs="0" type="tns:ExtensionType"/>

      </xs:sequence>

    </xs:extension>

  </xs:complexContent>

</xs:complexType>

    

<xs:complexType name="ExtensionType">

  <xs:sequence>

    <xs:any namespace="##other" maxOccurs="unbounded"/>

  </xs:sequence>

</xs:complexType>


	Kev

-- 
Kevin Conner
Arjuna Technologies Ltd.