RE: [wsn] Proposed requirement from WSDM

["Vambenepe, William N" <vbp@hp.com>]

Hi David,

 

The difference between this and the use of topics, is that this is useful in the case where the subscriber knows what is of interest to the consumer but the publisher doesn't. So the publisher cannot create a special topic for this.

 

For example, one the of the deliverables of WSDM is a way to manage Web services (the MOWS spec). In MOWS, we define a notification that is sent when a managed Web service receives a message (through its operational interface, not its management interface). In this notification, we'd like to pass the message that was received to trigger the notification. But this message can be huge. And maybe the only thing my manager really needs is one SOAP header out of the message. But the notification producer doesn't know that and wouldn't know to offer a specialized topic that is used to return messages that only contain the right SOAP header. On the other hand, the subscriber could specify this as part of the subscribe request.

 

Regards,

 

William

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From: David Hull [mailto:dmh@tibco.com]
Sent: Thursday, September 09, 2004 12:10 PM
Cc: wsn@lists.oasis-open.org
Subject: Re: [wsn] Proposed requirement from WSDM

+1 on "sounds like filtering on steroids"

The other instant reaction is "sounds like you're not making good use of topics."  I.e., each submessage should be on its own topic.  If you want more info, subscribe to more topics.  I'd like to see a strong use case that can only reasonably be solved by this kind of filtering.

That said, this could probably be treated as a particularly funky dialect of precondition.

Vambenepe, William N wrote:

Dear WSNers,

The WSDM TC would like to submit the following requirement to WSN:

"Add the option, when subscribing for notification, to specify that only
parts of the message should be sent. Note that the message that is sent
still needs to be schema-valid for the schema of the message."

The reasoning behind this requirement is that the content of the
notification message can get very large and in some cases only a subset
of this is of interest to the consumer. And in some cases, the
notification producer doesn't know what parts of the notification the
consumer is interested in, but the subscriber knows. So it should be
possible for the subscriber to express this in the subscription.

The WSDM TC would like WSN to add this to the WSN issues list.

Regards,

William

PS: doesn't it make us all feel good that Outlook wants to correct
"WSNers" to "Winners" on the first line of this email? ;-)