questions/concerns on initial working draft doc (and scope)

["Michael Shenfield" <mshenfield@rim.net>]

Hi all,
At the last conference call we had a discussion on taking the initial working draft to the general public. I suggested 'no' based on my initial impression from scanning through the document 2 weeks ago. Finally, past weekend I was able to review the document in detail. Here's the list of questions and/or concerns that I would like to post here for your review:

- Factory "resource". 
I am not sure about the concept of "factory" and passing observerURI as a part of CreateInstanceRq. Let's take Java Web Services as an example. When a Web Service deployed as a servlet the hosting Web Server container plays the role of the "factory" but this is "invisible" for the caller. The caller posts to the WS endpoint URI an HTTP request that contains the SOAP message to be invoked. Lifecycle management of the servlet (as a WS instance) is not covered by invocation protocol and therefore "creation" of the WS instance is non of the caller's concern. Similar model stands for the Web Services deployed as stateless session beans, the EJB container hides the creation process. For all async Web Services deployed at RIM (to support application initiated push to a wireless device) we have an "observer" URI (or rather requestor endpoint) passed as a part of the Web Service message. The requestor URI could also be submitted at registration (optionally with a correlationID), so that all following correlated and uncorrelated notifications could be posted to the requestor endpoint. This opens the stage for the next question:

- Multiple async responses for a single request or uncorrelated notification messages.
One of the possible deployments for async Web Services is when a single request causes a number of responses. As an example, one of our demo Web Services "Realtor" uses this model to send listings to a real estate agent registering a new client. The model is obviously asynchronous as we don't want our real estate clients wait (and pay for the airtime) till the request is processed. The "client registration" message is a request that carries the client search information, requestor endpoint URI and generated correlator ID to be used for responses. The server is doing the search in MLS and asynchronously sends found listings each in a separate SOAP message (here we have multiple responses for a single req). Moreover, when a new listing is posted to MLS the server is searching for interested clients and sends the listing to their agents as a notification (correlated notification model). Additionally, the Web Service is capable of sending uncorrelated notifications. We implement the following model: when real estate agent is logging in, the Realtor Web Service gets endpoint URI of the service proxy (linked with the device) and when a new information for the agent is available in the server (e.g. viewing appointment), the Web Service sends uncorrelated notification to the endpoint URI. In my opinion both models (multiple async responses and uncorrelated notification) should be included in the scope of ASAP 

- Monitoring support.
In the document there is a lot of discussion on monitoring the execution process and changing the state/properties during execution. I am not sure if this should be mandatory for compliance, one can perfectly deploy the async Web Service without support for monitoring or state change (see example above). Moreover, as an implementer I am not clear on how to implement this monitoring and state altering model in a scalable Web Service - in my opinion it contradicts basic scalability considerations of J2EE or .NET deployment. I think that ChangeState, GetProperties, SetProperties, and StateChange msgs should be changed to optional. As for Subscribe, Unsubscribe, and Completed, I am looking forward to the discussion on how it should be defined in the ASAP context.
Introducing monitoring of the execution is identical to polling for the completion/result and kills async efficiency. I understand the async paradigm as the model where requestor "calls and forgets". The implementation (and ASAP spec) should guarantee that the requestor gets the results (or notified on completion) when ready. Am I missing something here?

- Introduction Section. Language and terminology.
It looks like the verbage of section 1 intentionally deviates from the standard Web Services terminology and definitions. Is there a reason for this? Why should we call SOAP messages as "methods", Request data as "Context data", Response Data as "Results data", etc. Again, I might be mistaken here but my impression was that ASAP is strictly about Web Services?

Sorry to send this 20 mins prior to the conference call, but as I didn't see posted agenda we can as well discuss these points.
Cheers,

Michael Shenfield
Advanced Research Group
RIM
mshenfield@rim.net
905-629-4RIM x4347
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