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I agree WSDL documents should be generated rather than written by hand,
but doesn't schema provide means to pass trees around whose structure
you don't know (or at least, do not need to know for the sake of web
Generating WSDL dynamically (like creating a new type of service at
runtime) seems rather odd to me, because sure the invoker program has to
make sense out of the web service description. If some form of
negotiation takes place that leads to a new service, the form of this
negotiation is surely predetermined, and you don't really need to create
a new schema for that.
It might make sense for contexts, ports (e.g. suppose google rents out a
searching web service with 20.000 instead of 1.000 queries a day, they
generate the WSDL after payment has been confirmed.) But dynamically
changing the type of the data that goes over the wire does not happen there.
Maybe the point is that some specialization occurs (I am inspired by
what Mike Kay suggested, that later in a process you might want to apply
stricter validation). Suppose two components talking to each other,
finding out that they can both deal with more specific messages, and
then switch to the new protocol. But again, this requires that both know
the protocol (the schema tht is more specific) in advance.
Maybe some unanticipated reconfiguration mechanism might benefit from
dynamically generated schemas, but I am still missing a good example for
such a reconfigurable component.
What would be an ad-hoc interaction that involves the change in the type
Chiusano Joseph wrote:
>I have often thought about the concept of dynamically generated WSDL
>documents, for cases in which more ad-hoc interaction among systems
>needs to occur, perhaps driven by the context of a request. But I think
>we're a ways off from that in terms of standards and products - if it is
>indeed a useful concept.
>Booz Allen Hamilton
>Strategy and Technology Consultants to the World