Hi,
I have looked fairly closely into service metadata and SOA in general, and there are some useful things to note here:
Firstly, WSDL is good at defining the interface from a structural perspective - what messages and what are they composed of. It tells you absolutely nothing about the content being exposed by the service other than what you could infer from arbitrary type names in schemas - or by ringing up the person who set up the service!
WMS and WFS are well-known services - i.e. the structural component is pretty much fixed ( you could use WSDL to describe some of the variability). The "capability" documents are largely (but not exclusively) concerned with the content and related business rules. Future OGC specs should clean up consistency and better modularise these, and one would hope to see formal registration of WSDL specs for the services (service type WSDL) somewhere, with individual services just referencing these and adding the specific operation bindings they choose to support. Maybe some future "semantic WSDL" may provide a WSDL only solution.
In general, with well known interfaces you should not approach interoperability by generating stubs and coding business logic for each service instance, instead you should be able to build single interface classes with the business logic required to make sense of the content on offer from the service. i.e. automatically generated stubs will not buy you an awful lot of productivity because all the hard work has been done in advance in defining the service interface and semantics.
Hope this helps clarify the current state of play - who knows what the future will bring? But if you do know - please keep us all posted!
Regards
Rob Atkinson
I've a question about java development. I'm using Geoserver and its WFS/WMS webservices, and I'd like to know if there is a WSDL file for each of these services. This could allow me to use apache Axis to generate client java classes, that could deal with a WFS or WMS service. I didn't find a generic WSDL file for WFS/WMS. Maybe I should have another look to the OGC specs... or should I make calls to WFS only with HTTP queries?
Thanks