An endpoint handler of requests passing through WebAppTool and
WebAppToolSink that works in a canonical way - it dispatches
"like-for-like" in that HTTP GETs and POSTs originating from the
client are mapped onto the same, and the remote servlet is
provided with enough context to allow it to compute ultimate
URLs by itself, obviating the need for rewriting.
Individual tool handlers override the adjustRequest
method which is provided with a freely writeable parameter map
object into which should be put any extra parameters required
to deal with the request (e.g.
InformationServlet represents a generalised web service handler.
The portion of the URL after the servlet mapping is used as an index
into a table of InformationHandler objects, which are handed the
deserialised argument decoded from the request body.