The EA version of the JAXB binding schema had <interface>s that allowed for the
polymorphic use of elements (for example: a choice group of elements could be
treated as a collection of an interface if each of the choice elements was
listed as a member of the <interface>). This has proved most useful to me in the
work I've done with the EA version.
When I heard about the new version of JAXB mapping schema types to interfaces I
thought this sounded like the prefect answer to the messiness of the <interface>
definition. Using xsi:type or subsitutionGroups this could all be specified
using schema mechanisims without having to list them explicitly in the binding
schema. And even better, through <xsd:import> we could add new
sub-interfaces/classes to these types without modifing the base schema or bindings.
How come then the 0.75 spec states that xsi:type and substitutionGroup are not
required to be supported by a JAXB implementation - as this IMHO seems to be a
fundamental feature and an obvious use of the type hierarchy that JAXB builds
from XML schemas. What use is mapping schema types to java interfaces if we
can't make use of them in our schemas?
regards,
Damon.