RE: Re: Query / Response type messages

[Patrick Lidstone \(Personal E-mail\)]

> -----Original Message--
> 3) I like the way WHA puts the query back in the response message;
> makes things more stateless. You could argue that it is already
> implicit in BSC so no need to add it.

This is a really sound design policy/best practice, and should be
"policy" IMO.
Reliable xAP applications MUST be stateless (in terms
of dependencies between successive messages) because of the possibility
of message loss. Including what I would call a "context envelope"
in
the response obviously restricts the size of the request, but the robust
approach wins out. There is a case to be made for permitting the
inclusion
of private, opaque, sender-specific data as part of the context envelope
as necessary.
As a side note, the technique can occasionally be useful with generic
broadcast interactions, although it's most useful when targeting
messages.

Patrick