[sdo] [SDO-6]: Reference properties and JAXB 2.0

[Radu Preotiuc-Pietro <radup@bea.com>]

Omar Halaseh:
These are comments from Blaise Doughan:

"JAXB 2.0 (Referential Integrity, page 226) describes two possible
strategies for marshalling referenced properties:"

While the JAXB 2.0 spec does offer two options (page 224 on the latest
version of the spec). As a member of the JAXB 2.0 expert group I can say
that it is currently expected that all relationships for a property be
of the same type (all containment or all reference). Relationships are
containment by default and the @XMLID & @XMLIDRef annotations can be
used to make the relationships by reference.

—

"To have closure, the first option forces you to have these referenced
objects contained in some root data object in schema. This is a
requirement in XML only, and its not required in the object
representation in Java as referenced objects are treated just like
contained objects from an object access point of view."

While Java does not make a distinction between references and contained
objects, SDO does. SDO properties are explicity reference or containment
based on the "isContainment" property.

Changes would need to be made to Property to have it act as both
containment and reference.

—

"<xsd:complexType name="Line" Type="Line">
<xsd:sequence>
<xsd:element name="ID" type="xsd:int">
<xsd:element name="Buyer" type="BuyerType"
sdo:marshalReferenceInPlace=true/>
</xsd:sequence>
</xsd:complexType>"

If this is the XML Schema then the "Buyer" element will need to specify
the nodes defined in "BuyerType". It won't be possbile to just replace
the expected "Buyer" element with <Buyer sdo:ref="456"/>.

Changes would need to be made to the XML Schema. This would impact
XSDHelper and XMLHelper.


Steve Brodsky:
People who start with XSD will not be able to understand documents with
behavior that has object reference serialization rules.



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