W3C home > Mailing lists > Public > xml-dist-app@w3.org > December 2005

Re: What it means to "get rid of MEPs"

From: Francisco Curbera <curbera@us.ibm.com>
Date: Fri, 23 Dec 2005 19:47:48 -0500
To: Noah Mendelsohn <noah_mendelsohn@us.ibm.com>
Cc: David Hull <dmh@tibco.com>, Rich Salz <rsalz@datapower.com>, xml-dist-app@w3.org, xml-dist-app-request@w3.org
Message-ID: <OF3BFB1B87.310A2F12-ON852570E1.00038609-852570E1.000460BE@us.ibm.com>

There seems to be is a common misundertanding about whether mustUnderstand
can replace the need for service contracts. AFAIK, mustUnderstand provides
senders (clients) with the ability to state their own requirements (client
side contract) at runtime. mU does not cover receiver (server) side
requirements, that is, server side contracts.

Whether the receiver side contract needs to be explicitly provided (as WSDL
or something else) depends on the specific use case. I fully agree (as Rich
says, who doesn't?) that SOAP itself has no dependency on WSDL.


                      Mendelsohn/Cambridg        To:       Rich Salz <rsalz@datapower.com>                                          
                      e/IBM@Lotus                cc:       David Hull <dmh@tibco.com>, xml-dist-app@w3.org                          
                      Sent by:                   Subject:  Re: What it means to "get rid of MEPs"                                   
                      12/23/2005 06:19 PM                                                                                           

Rich Salz wrote:

> Noah Mendelsohn wrote:

> > SOAP needs to stand on its own without WSDL.

> Is there anyone here who disagrees with this?

Well, there certainly have been times recently when I've thought I heard
people say words to the effect:  we don't need MEPs in SOAP and/or we
don't need detail X to be covered by MEPs in SOAP because WSDL will be
there to provide the answer.   Maybe or maybe not the implication is to
suggest an inappropriate dependence of SOAP on WSDL, but I think there is
at least a risk that we would inadvertently fail to take enough care in
having SOAP stand on its own.  As I think I mentioned earlier, even those
servers that are themselves built with the help of WSDL benefit from an
ability to interact with software (e.g. built in scripting languages) that
may not be WSDL-based.  Of course, everyone involved needs to agree on the
contract, or safely realize that they haven't agreed.  The good news is
that SOAP provides you pretty good ways of using mustUnderstand and
(crucially in this case) binding specifications to check on the level of
agreement without necessarily using WSDL.

Noah Mendelsohn
IBM Corporation
One Rogers Street
Cambridge, MA 02142
Received on Saturday, 24 December 2005 00:48:05 UTC

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