Comments inline:

On Fri, 2005-01-14 at 23:35 -0500, Ian Springer wrote:
> (14:23:02) ips: what do u think of renaming SubscriptionManager to
> Subscription ?
> (14:23:20) ips: since it represents a single subscription
> (14:23:41) lischke: :-) in my impl Subscription implements
> SubscriptionManager, so i would like to see that on the API too
> (14:23:53) ips: ok, let's change then
> (14:23:57) ips: makes it more inutitive
> (14:24:11) lischke: +
> (14:24:13) lischke: 1
> (14:24:24) ips: to me, the name subscriptionmanager implies a class that
> manages multiple subs
> (14:24:43) ips: will methods be added to TopicFilter and XPathFilter?
> (14:25:08) lischke: i dunno i just added them....
> (14:25:44) lischke: maybe in future
> (14:26:19) lischke: you changed SubscriptionManager->Subscription or me?
> (14:28:28) lischke: things to discuss: callback methods deliver() and
> end() and the parameters...... sam wants to put subscriptionpolicy in
> subscribe method too, but i cannot model that in wse... i think the
> Filter is enough

On the policy front: I believe that there are some arguments that will
for the time being have to be ignored by eventing.

> (15:16:50) ips: i'm curious why were the fields in Status split out into
> another object instead of putting them in Subscription?

For extensibility reasons mostly. Both the rp document and the eventing
get status reply are open content so I figured it would be good to have
another factory like method here.

> (15:52:31) lischke: can we change subscribe(....filter[]...) to
> subscribe(... filter...) and allow filter to have subfilters? then we
> have one filter, which may contain a selector, precondition and maybe a
> subscriptionpolicy
> (15:53:09) lischke: so filter contains array of filter
> (15:53:16) ips: sounds good to me
> (15:53:59) ips: can we change dialect from String to java.net.URI?
> (15:57:40) lischke: yeah and maybe change name :-) cause it conflicts
> with wse FilterType which has also getDialect :-)
> (15:57:59) lischke: maybe getURI ?
> (15:58:32) lischke: but name changing is not that importand
> (16:12:10) lischke: if we change filter[] to filter and make a bigger
> filter concept out of it containing selector, precondition ..... then we
> should change Status and only do get/setFilter() instead of get/set all
> selector.....
> (16:13:02) lischke: maybe you are right, and Subscription should be
> derived from Status
> (16:33:23) ips: i think we should stick w/ an array of filters
> (16:33:55) scamp: tsk tsk they didn't lock down their dirs!
> http://saturn.jpl.nasa.gov/multimedia/videos/movies/
> (16:34:04) ips: precondition and selector are defined by basenotif
> (16:34:26) ips: so they really have nothing to do w/ topicexpression
> (16:34:32) ips: just another form of filter
> (16:35:41) ips: they prolly don't need to be in the pubsub interfaces at
> all
> (16:35:53) ips: since they're WSN-specific

I suggested Filter[] because even from a message modeling pov WS-BaseN
is headed down that path (I suspect there will be a action item during
the next f2f for combing both selector, precondition and topic
expression into a number of filter elements). 

A few more thoughts:

* On the subscription store front I really do not see the need to invent
a new API. What is wrong with the resource home concept/APIs? I also
don't see why we can't just have one big subscription home?

* Evaluating filters: I would rather leave this up to the 2 different
implementations rather than trying to come up with a common API (which
is definitely going to clash with our existing WS-N APIs). In general
the problem seems to me one of how you view your subscriptions working.
The two approaches I see are:

        1) You have a single stream per producing resource to which 
           you continuously apply filters
        2) You subdivide you stream into a hierarchy of streams (in 
           some sense these are server defined filters rather than 
           client defined filters) and then apply the client provided 
           filters to the substreams.    

WS-E has imo chosen 1 and WS-N has chosen 2. While you could also model
2 as 1 I think it makes more sense to model 2 somewhat differently
(since the number of predefined filters is somewhat fixed you can
explicitly model them). In conculsion, I do not think you can come up
with a common API if you want to explicitly model 2 which is what we
chose to do for WS-N. Hmm, on the other hand you can come up with a API
for filtering streams and apply it to the big stream in 1 as well as the
substreams in 2. It would mean treating some filters (topics) in the
subscription API differently from other filters though, but maybe that
is acceptable?

/Sam

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-- 
Sam Meder <[EMAIL PROTECTED]>
The Globus Alliance - University of Chicago
630-252-1752



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