What kind of Web Service is this?

[Steve Cohen]

I am trying to develop client code for a vendor-provided service of a 
type I've never seen before.  The vendor does not provide a WSDL, but 
they do provide an XSD schema definition, a URL, and a protocol document 
in which it is explained that the request parameters are provided as 
query parameters appended to the URL itself ?key1="value"&key2="value", 
etc.  The XSD does not define a request packet but it does define the 
response packet.

Is there a name for this type of Web Service?  (Is it even considered a 
Web Service?)  And are there facilities in CXF (or other systems) for 
generating client code based on it?  Or am I better off just writing my 
own parsers for the response?