Callback interface for extracting a result object from a
WebServiceMessage instance.
Used for output object creation in
WebServiceTemplate. Alternatively, output messages can also be returned to
client code as-is. In case of a message as execution result, you will almost always want to implement a
WebServiceMessageExtractor, to be able to read the message in a managed fashion, with the connection
still open while reading the message.
Implementations of this interface perform the actual work of extracting results, but don't need to worry about
exception handling, or resource handling.