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RE: Reference requirements

From: Liu, Kevin <kevin.liu@sap.com>
Date: Fri, 1 Mar 2002 23:49:06 +0100
Message-ID: <5144A3121B37D411BC0100508B955A1808B94264@uspalx20>
To: "'Paul Prescod'" <paul@prescod.net>
Cc: "'www-ws-desc@w3.org'" <www-ws-desc@w3.org>
Hi Paul, Please see my comments below marked [KL]

> 1. Does it make sense to pass by references if the services is stateless?
Is
> it a good idea to keep a web services stateful?

How could a web service be entirely stateless? If I submit a purchase
order and want to check up on its status a week later, doesn't that
require state? How do I even tell the company what customer I am so they
can check my payment history?

[KL] State management and stateful objects are two different things. All
applications need to manage state somehow, stateful object is only one way
to do that. Even in a 'classic' n-tier application, many people consider
stateful object as not scalable. 
  
In your example, Do you mean you want to keep your stateful object alive for
a week?

> 2. What's the benefit of passing by references vs.  passing by value
across
> Internet ?

It's simply the case that almost all serious business problems involve
references to things that have already gone before. Those are
references.

[KL] Again, referencing an object and passing an object by reference, in my
opinion a two different thing. In the WSDL interface term, passing by
reference is more relevant. 

> 3. As for WSDL, it already has some construct for expressing in/out
> parameters using ParameterOrder attribute of Operation - any needs to go
> further?

That's an unrelated feature.
[KL] Can you explain?

 Paul Prescod
Received on Friday, 1 March 2002 17:49:41 GMT

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