When providing a web services API (well, let's say SOAP), do you provide a library wrapper along with it to make it "easier" for people to use? Or do you just package up a WSDL and documentation for it and let people figure out what to do with it?
What are people doing usually? I've seen a bunch of examples where the wrapper is provided, but it has always seemed counter-productive to me.
WSDL is easily discoverable (all functions & types as declared), so there is usually no need to offer any package with it, and minimal documentation (apply an XSL to the WDSL and it's usually enough :) ). My theory about the appearance of libraries/wrappers is that it is directly related to security measures / needed authentication & hashes (usually: concatenating some fields with a secret & hash it), about which one simply doesn't want to answer every single question anymore.
Audience matters I think: if you want you run-of-the-mill hobby coder to be able to use your service, providing a package can get you that much more users. If you're more in business to business services, the webservice usually has to be integrated in some larger package and most libraries would be futile.
That being said, I'd say of the webservices I came across: about 60% of the libraries provided were hopeless spaghetti code fit for the bin, 30% were not the code I'd use, but could clear up some questions not answered by the documentation, and only about 10% were fit enough to integrate in a project (or the project small and/or worse enough to be no worse for it).
How you going to support multiple web-service stacks - JAX-WS, AXIS2, CXF etc? My choice - WSDL/XSD. In practice I got service built with JAX-WS and a client with AXIS2. And I don't want to build a client wich you are going to use. I don't even know your preferable web-service stack and your JVM version limitations. For example, I can call web-service from java 1.4 - there are no annotations and not possible to use client lib built with annotations for java 1.5. So WSDL is right way to build ws-client instead of providing generated client library.