Re: [xml-dev] REST, SOAP, Speech Acts and the mustUnderstand model of SOA communications (was: Re: What Does SOAP/WS Do that A REST System Can't?)

[Joe Gregorio <joe.gregorio@gmail.com>]

Excellent, an enumeration is the right way to go with this. The advantage
is that you can then dip into negative numbers:

xml:mustUnderstand="-1" - The recipient MUST NOT understand 
the message fragment. 

xml:mustUnderstand="-2" - The recipient MUST willfully misinterpret
the message fragment. 

xml:mustUnderstand="-3" - The recipient MUST willfully misinterpret
part of the message while generating error messages that include
ad hominem attacks on the author of the message fragment.

xml:mustUnderstand="-5" - The recipient MUST willfully misinterpret
part of the message in a libelous manner while claiming to have 
invented the format and claiming you are using it wrong.

   -joe


On Apr 1, 2005 2:21 AM, Sean McGrath <sean.mcgrath@propylon.com> wrote:
> Whatever about the pros and cons of REST versus SOAP, I think it is
> abundantly clear that the mustUnderstand model [1] is a key concept in
> developing loosely coupled systems that can evolve independently.
> 
> I would like to suggest that the mustUnderstand model is sufficiently
> important that it should be added to the xml namespace alongside
> xml:space and xml:lang.
> 
> I'm a big fan of conceptualising XML message exchange in terms of
> Speech Acts[2]. To make the most of the power of this abstraction, I
> think it is necessary to extend the coarse boolean mustUnderstand
> model into a more fine grained model that matches the way speech acts
> are used in the real world.
> 
> I would like to suggest that xml:mustUnderstand be an enumeration with
> a number of positive integer values, the semantics of which, should be
> part of the specification. I can think of five.
> 
> Additions/comments on these welcome:
> 
> xml:mustUnderstand="0" - It is permissable for the recipient to not
> understand the message fragment. No specific directions about the
> speech act semantics in this case.
> 
> xml:mustUnderstand="1" - The message fragment must be understood,
> otherwise the conversation must fail.
> 
> xml:mustUnderstand="2" - reciever must claim to understand, even if it
> does not. The sender should have not be able to tell whether or not
> the receiver really understands or is simply claiming to
> understand. This is particularly useful in the service industries.
> 
> xml:mustUnderstand="3" - receiver may at first issue one or more
> failure responses indicating that it does not understand the message
> fragment. Then, without any action from the sender other than retries,
> the receiver begins to understand the message fragment. This has many
> applications in the political arena.
> 
> xml:mustUnderstand="4" - reciever may claim to understand the message
> fragment one or more times and then begin issuing failure
> responses. The failure responses should indicate that the message was
> never understood and assert that the receivers behavior has been
> consistent in this regard all along. This has many applications in the
> media and in academia.
> 
> xml:mustUnderstand="5" - reciever may claim not to understand but,
> unknown to the sender, may act upon the message fragment. This has
> many applications in e-commerce.
> 
> Thoughts?
> 
> Sean
> seanmcgrath.blogspot.com
> 
> [1]
> http://www.pacificspirit.com/blog/2004/07/27/dare%20versioning%20extensibility%20article%20comparison
> 
> [2]
> http://www.manageability.org/blog/stuff/the-restfulness-of-speech-acts/view
> 
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-- 
Joe Gregorio        http://bitworking.org