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Re: service references (was: Re: WSA diffs from REST)

From: Paul Prescod <paul@prescod.net>
Date: Mon, 23 Sep 2002 15:28:37 -0700
Message-ID: <3D8F9595.4040206@prescod.net>
To: Sanjiva Weerawarana <sanjiva@watson.ibm.com>
CC: Mark Baker <distobj@acm.org>, www-ws-arch@w3.org

Sanjiva Weerawarana wrote:
> "Paul Prescod" <paul@prescod.net> writes:
> 
>>As an example, I am willing to bet a substantial amount of money (but in 
>>Canadian dollars) that [1] will also be an issue that will require TAG 
>>intervention if it is not fixed by the relevant working group:
>>
>>  * http://www.blogstream.com/pauls/1032521623
> 
> 
> All that's needed is a notion of service references and the ability
> for a WSDL part to say its of a certain reference type. That's it.

Do you mean "port" or "part". And if "part" then why not "element"? 
Parts don't don't have minoccurs. They don't have maxoccurs. They can't 
be mixed in with metadata about the reference.

> BPEL4WS already introduces a version of service ref.

I'm trying to understand it. How would it handle the situation where I 
have an interface like:

interface PurchaseOrder{
    ...
}

interface PurchaseOrderManager{
     PurchaseOrderReference createNew(PurchaseOrder po);
     boolean update(PurchaseOrder po)
     boolean updateFromReference(PurchaseOrderReference po)
}

What is the SOAP+WSDL+BPEL4WS representation?



This is an even more fundamental divergence from the Web model than 
anything labelled REST or GET etc. And to boot, it is a divergence from 
all of the other models like OO, pub/sub, etc. You *do not know* all of 
the services you need to talk to at design time, anymore than a Java 
program has a list of the objects it is going to create at design time.

>...
> I'm surprised your article takes the tone that the people doing
> WS stuff are so dumb as to not want or understand the need for
> certain functionality. 

The problem has been evident since SOAP 1.0 and the first versions of 
SOAP toolkits shipped. That was three (!) years ago.

For more than a year I've been agitating and getting very little 
traction (most often to responses of: "Why do we need that?"). My 
observation is that it has taken some "tone" to get people thinking. 
Better I use tone now then wait around and have the TAG mandate a deep 
rewrite of WSDL later.

Furthermore, this is a major architectural shift which will impact all 
of the other specifications and literally hundreds of SOAP tools. It 
would be better to address it sooner rather than later.

 > This is just a simple feature and a
 > solution to half of it was already published in the BPEL spec.
 > The rest will come too - soon.

Let's continue with the analogy of Java. If Java version 1 only allowed 
references to classes and static methods and Java version 2 added the 
concept of object instances, would you say that's a "simple feature"? It 
seems rather major to me.

  Paul Prescod
Received on Monday, 23 September 2002 18:29:11 GMT

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