Abstract base class for endpoints that handle the message payload with a SAX ContentHandler. Allows
subclasses to create a response by returning a Source.
Implementations of this class should create a new handler for each call of createContentHandler, because
of thread safety. The handlers is later passed on to createResponse, so it can be used for holding
request-specific state.
ContentHandler. Allows subclasses to create a response by returning aSource. Implementations of this class should create a new handler for each call ofcreateContentHandler, because of thread safety. The handlers is later passed on tocreateResponse, so it can be used for holding request-specific state.