Question

I have an interesting XML situation in which I’m trying to write an XSD for. The web service I am using has an unusual way of sending responses in that it is generic in a way.

For example,

Web Service Call 1:

<rootElement>
  <result>
    <resultset>
      <row attr="some value" attr2="some value 2" />
    </resultset>
  </result>
</rootElement>

Web Service Call 2:

<rootElement>
  <result>
    <resultset>
      <row someOtherAttr="some value" someOtherAttr2="some value 2" />
    </resultset>
  </result>
</rootElement>

As you can see, the only thing that differentiates the two web service responses is the attributes within the row element.

I’ve tried a few different approaches by having an abstract element for the result element, which works to a point, but I can’t figure out how allow JAXB to choose which result element to use when marshalling.

i.e.

... other xs declarations excluded for sanity ...
<xs:element ref="abstractResult" />
... snip ...

<xs:element name="abstractResult" type="ResultType" abstract="true" />

<xs:complexType name="ResultType" abstract="true" />

<xs:complexType name="SomeResultType">
  <xs:complexContent>
    <xs:extension base="ResultType">
... snip ...

The problem with this approach is JAXB tries to instantiate the abstract ResultType while marshalling rather than searching for a proper implementation.

Is there any way to avoid this?

Thanks a bunch!

Answer 1

Ended up separating the schemas into independent files in which there are the different implementations of the root element.

I then tied the multiple schemas to their own namespace so the marshaller is able to differentiate between the similar elements.

Since the xml comes in without a namespace from the webservice, I am using JDom to set the namespace since I know what the target object type will be at runtime.

Hope this helps anyone interested.