RE: [wsn] New Issue: SubscriptionManager Interface in BrokeredNotification

[Steve Graham <sggraham@us.ibm.com>]

"Patil, Sanjay" <sanjay.patil@sap.com>
wrote on 03/03/2005 10:18:05 PM:

> Hi Steve,
>  
> I wasn't suggesting to merge the SubscriptionManager
interface into the 
> NotificationBroker interface. Rather I was thinking if it makes sense
to include 
> the SubscriptionManager interface definition in the WS-NotificationBroker
WSDL file
> for the sake of completeness.
Ah ok, sorry for the misunderstanding.  Would
you imagine this could be accomplished
by use of wsdl:import, or do you suggest the SubscriptionManager
interface be defined
in the WS-Brokered Notification namespace as well?

>  
> Regarding the net effect of introducing a broker
intermediary ... I agree that we 
> should allow the NotificationBroker to delegate the SubcriptionManager
> functionality. Taking the same line of argument, should we then also
allow the 
> broker to delegate the NotificationConsumer as well as NotificationProducer
> behaviors. Why should  we require that there be a single aggregate
> NotificationBroker interface (and therefore a single endpoint!) that
supports 
> operations from the NotificationConsumer and the NotificationProducer
interfaces? 
Good question.  To me, the motivation for the
aggregation is that it is exactly
the combination of the consumer (for publish) and
producer (for subscribe etc.) that
is the essence of what it means to be a broker, hence
it seems to make sense to combine
these into one interface. 

>  
> Thanks,
> Sanjay
> -----Original Message-----
> From: Steve Graham [mailto:sggraham@us.ibm.com] 
> Sent: Wednesday, Mar 02, 2005 4:28 AM
> To: Patil, Sanjay
> Cc: Lily Liu; wsn@lists.oasis-open.org
> Subject: RE: [wsn] New Issue: SubscriptionManager Interface in BrokeredNotification

> 
> "Patil, Sanjay" <sanjay.patil@sap.com> wrote on 03/01/2005
10:15:14 PM:
> 
> > I believe the intent here may have been to point out that the
broker role is a 
> > composition of producer and consumer roles. However, I am with
you in that we 
> > should clarify whether and how this role composition translates
to assuming support
> > for WSDL Interfaces. 
> With respect to the composition of the producer and consumer roles,
this is 
> captured in the NotificationBroker portType.  What is missing
from that? 
> 
> >   
> > In addition to clarification text in the spec, the WSDL/Schema
for the  BrokeredN 
> > should perhaps also include a copy of the SubscriptionManager
PortType from the 
> > BaseN. Or should there be a wsdl:include of BaseN WSDL in the
BrokeredN WSDL? 
> I am not sure we should increase the size of the WSDL/Schema for BrokeredN.
 Why 
> is it not sufficient for the Broker to delegate to another SM service?
> Another alternative to this issue is to modify the requirement text:
> 
> (starting line 100 of the 21 July 2004 draft of BrokeredN): 
> Must allow for a notification broker as an intermediary. A 
> NotificationBroker is an intermediary Web service that decouples 
> NotificationConsumers from Publishers. A notification broker can relieve
a 
> Publisher from having to implement message exchanges associated with
> NotificationProducer; the NotificationBroker takes on the duties of
a 
> SubscriptionManager (managing subscriptions) and NotificationProducer
> (distributing NotificationMessages) on behalf of the Publisher. 
> 
> Perhaps it is the "takes on the duties of a SubscriptionManager"
that is the 
> text in concern?  We could rephrase that to include the notion
that 
> a NB could implement SM or it could delegate the behavior.  The
net result is 
> that the responsibility of managing subscriptions is removed from
the publisher 
> by the Broker. 
> 
> >   
> > Thanks, 
> > Sanjay 
> > -----Original Message-----
> > From: Lily Liu [mailto:lily.liu@webmethods.com] 
> > Sent: Tuesday, Mar 01, 2005 9:43 AM
> > To: wsn@lists.oasis-open.org
> > Subject: [wsn] New Issue: SubscriptionManager Interface in BrokeredNotification
> 
> > In the WS-BrokeredNotification specification, it states that
a broker should take 
> > on subscription manager duties in the Requirement section. However,
it only lists 
> > out two interfaces that a NotificationBroker inherits: NotificationProducer
and 
> > NotificationConsumer. I think we should add SubscriptionManager
to that list. 
> >   
> > Lily