W3C home > Mailing lists > Public > public-ws-chor@w3.org > February 2004

Re: WSDL and pub/sub

From: Farrukh Najmi <Farrukh.Najmi@Sun.COM>
Date: Tue, 17 Feb 2004 14:01:38 -0500
To: david.burdett@commerceone.com
Cc: chiusano_joseph@bah.com, UCorda@SeeBeyond.com, Monica.Martin@Sun.COM, andyb@whyanbeel.net, steve@enigmatec.net, public-ws-chor@w3.org
Message-id: <40326512.40903@sun.com>

david.burdett@commerceone.com wrote:

>Thanks for the explanation, it makes sense. Here's another question as I am really trying to get my mind around this ...
>Suppose, that you want to build an auction capability using the the following services, for example:
>1. User Registration - registers a user
>2. Auction Registration - records a registered user's interest in an auction
>3. Bid Placement - a user that has registered an interest in an auction places a bid
>4. Bid Notification - users that have registered an interest are notified of successful bids placed
>4. Bid Result - the winner of the auction (if any) and other interested users are notified of the result of the auction
>3. Winning Bid Payment - the winner of the auction pays, by credit card
>Let's go further and assume that:
>1. There are existing User Registration and Winning Bid Payment services that the operator of the auction wants to use
>2. Bids are not automatically accepted, for example they must be higher than any previous bid and perhaps mulitples of $10, if that what the auction rule says
>3. Users must be registered before they can bid.
>This sounds to me to be more than what the ebXML Resistry was designed for.
I agree that this is begining to sound like an Auction application that 
use ebXML Registry in its
implementation. Even so, the ebXML Registry can provided much more than 
one might think. For example it can do the following:

-Serve as a User Registration service based upon strong DSIG based 
authentication and custom  Role Based Access Control using XACML 1.0 

-Allow app specific content validation to be applied before accepting a 
content (e.g. Bid lower than highest bid wont be accepted, Users must be 
registered before they can bid.)

>So some more questions:
>1. Could you sensibly use the pub/sub part of ebXML RR in the above example.
I believe you can. It can provide some basic features that the 
application can be built upon.

>2. If you can, you still have the problem of defining how you combine the ebXML RR pub/sub protocol with other existing protocols to ensure that they occur in the correct sequence.
>Don't misunderstand me, I do think that ebXML RR has great value in maintaining information about "static" objects, e.g. WSDL definitions, schemas, etc, I'm just not sure that it is the appropriate technology to use for this use case.
Just to clarify. I stated early in this thread that:

"I too occasionally wonder about whether registries *SHOULD* play a role 
in multi-party collaboration but have no doubt about their need to 
support a content based event notification feature."

But I have no doubts that it *COULD* be used for this use case .

If one views the registry like a database for web services as I do then 
I do not see this use case as an abuse of ebXML Registry. Many people 
are using ebXML Registry as a general purpose database/CMS for web services.

I defer to you and other ws-choreography folks on whether such uses of 
ebXML Registry make sense for this use case.

>-----Original Message-----
>From: Farrukh Najmi [mailto:Farrukh.Najmi@Sun.COM]
>Sent: Tuesday, February 17, 2004 4:39 AM
>To: Burdett, David
>Cc: chiusano_joseph@bah.com; UCorda@SeeBeyond.com;
>Monica.Martin@Sun.COM; andyb@whyanbeel.net; steve@enigmatec.net;
>Subject: Re: WSDL and pub/sub
>david.burdett@commerceone.com wrote:
>>Monica, Joseph, Ugo et al
>>A question. Just suppose you wanted to use the ebXML RR spec with other XML documents designed to support the Auction use case I described earlier, would there be any issues that you can think of. For example ... would you need to have an ebXML Registry to store information about Auction objects?
>Funny you should mention an auction scenario and ebXML Registry. See a 
>recent exchange below where I used the same scenario in the context of 
>ebXML Registry event notification.
>I feel that ebXML Registry event notification could be used to support 
>multi-party collaboration scenarios as the next logical step from binary 
>collaborations exemplified by ebXML Messaging and SOAP.
>As it currently stands, registry events are only triggered when a 
>CREATE/UPADTE/DELETE operation occurs
>in the registry. For example a BiddableObject must be written to 
>registry to represent that something is open for bids. Bidders would be 
>subscribed to BiddableObjects and will be notified. They can then write 
>Bid objects to the registry. The auctioneer would be subscribed to Bids 
>for "their" BiddableObjects and will be notified when a Bid is placed. 
>They would have to write a BidResult object to registry when bidding 
>closes and all Bidders would be notified of the BidResult.
>So yes several objects would have to be written to the registry in order 
>to support this scenario.

Received on Tuesday, 17 February 2004 14:01:42 UTC

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