Re: WSDL 2.0 element order enforcement in schema

On Wed, 6 Jul 2005 09:58:52 -0400
Lawrence Mandel <> wrote:
> Following from this description, can someone give me an example of a 
> problem that may arise if the schema is defined as follows? (I updated it 
> to allow extensibility elements before the types element.)

Ambiguous content model.  Not allowed in schema; likely to be triggered
by anyElement when other content is optional.

Specifically, if you have:

  <other:random />

you don't know whether that's the any paired with include/import or the
one that interleaves with interface/binding/service; you don't know,
because types is optional, whether to expect types, interface/service/
binding/any, or what.

UPA.  We keep tripping over it.  The WSDL 1.1 schema has a similar

(tangentially, this is not a problem for RNG, and it is known that some
schema validators refuse to implement the UPA constraint.  However,
we're sorta stuck here.  We can't get all the way to accurate, and the
more complex we get, the less likely it is that people will look at the
(normative) text.)

Hmmm.  I'd recommend that we document this in our schema, including
text to the effect:

The content model of the documentation element as represented in schema
is not complete.  Validators MUST implement the constraints as
specified in [specref], which permits extension elements in more
locations than we can show in a schema that abides by the UPA

Amelia A. Lewis
Senior Architect
TIBCO/Extensibility, Inc.

Received on Wednesday, 6 July 2005 14:22:48 UTC