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RE: Action Item 2004-07-01 Solution to 168/R114

From: Jim Webber <Jim.Webber@newcastle.ac.uk>
Date: Wed, 14 Jul 2004 01:23:43 +0100
Message-ID: <37E80E80B681A24B8F768D607373CA800103DA8B@largo.campus.ncl.ac.uk>
To: <www-ws-desc@w3.org>

Prasad:

> I can relate to leaving this to the complexities of server 
> side implementation to figure how to dispatch the message (to 
> the correct operation), even though I do see cases where this 
> can become difficult (having to parse the entire message to 
> determine the "real" operation (performance issue))  if not 
> totally ambiguous in the worst case.

The performance of a service is not the consumer's responsibility. If
you want a high-performance service then architect it that way, but
don't delegate your service's needs to the consumer.
 
> If we can make it easier for a client to direct a message at 
> an operation  on the server in a guaranteed fashion (from the 
> client perspective), it is really useful IMO. This gets my 
> vote on "what the WG wants" vs what 114 means.

No it's not useful because i)operations are imaginary (a function of a
particular view of a message; and ii) this violates encapsulation and
encourages consumers to bind to something that they shouldn't (both
because it's intangible and because its yours not theirs).

> 1. In promoting the client and server sides having the same 
> understanding on what is being invoked unambiguously (goes 
> towards interop).

This is, I believe, emminently achievable through the structure and
content of messages.
 
> 2. Avoid debug head-aches on the server implementation when 
> things *do* go wrong.

You're right here, sort of. The first time something breaks you've got a
head start because you immediately know what operation is causing the
problem. However over time as your service evolves and perhaps the
wsdl:operation and the com.foo.Bar.operation() method become more
detached (perhaps completely) then you're at the same place I am with
just a bunch of messages that have to be matched to some back-end
system.

So in the general case you get nothing from mixing in operation names,
apart from undesirable tight-coupling.

Jim
--
http://jim.webber.name 
Received on Tuesday, 13 July 2004 20:21:54 GMT

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