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RE: [wsia] [wsrp] [wsrp-wsia joint interfaces] Merged interfacesdocument

  • 1.  RE: [wsia] [wsrp] [wsrp-wsia joint interfaces] Merged interfacesdocument

    Posted 06-10-2002 10:50
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    Subject: RE: [wsia] [wsrp] [wsrp-wsia joint interfaces] Merged interfacesdocument


    Kirk -
    
    2. I believe you are right and the null handle is semantically inkonsistent
    with the rest of the spec. I think we may want to specify that a provider
    must return a handle in any case. For a stateless service this might be
    just a constant handle so it does not impose much overhead for the
    producer.
    
    Your remark for stateful services: as Rich pointed out there are
    initiatives to intoduce statefulness in WSDL. However these will neither be
    finished in the near future not will this be implemented in the standard
    SOAP stacks in the next few month. Given our WSRP schedule I think that at
    the moment we cannot live without defining the statefulness ourselves.
    
    
    Best regards
    Carsten Leue
    
    -------
    Dr. Carsten Leue
    Dept.8288, IBM Laboratory B�blingen , Germany
    Tel.: +49-7031-16-4603, Fax: +49-7031-16-4401
    
    
    
    |---------+---------------------------->
    |         |           Rich             |
    |         |           Thompson/Watson/I|
    |         |           BM@IBMUS         |
    |         |                            |
    |         |           06/10/2002 01:00 |
    |         |           PM               |
    |         |           Please respond to|
    |         |           Rich Thompson    |
    |         |                            |
    |---------+---------------------------->
      >---------------------------------------------------------------------------------------------------------------------------------------------|
      |                                                                                                                                             |
      |       To:       wsia@lists.oasis-open.org, wsrp@lists.oasis-open.org                                                                        |
      |       cc:                                                                                                                                   |
      |       Subject:  RE: [wsia] [wsrp] [wsrp-wsia joint interfaces] Merged interfaces  document                                                  |
      |                                                                                                                                             |
      |                                                                                                                                             |
      >---------------------------------------------------------------------------------------------------------------------------------------------|
    
    
    
    
    I would agree that not enough definition of fault messages (& when they
    may/must be generated) has been worked through yet, but hope that we are
    getting far enough on the appropriate concepts that time should be spent on
    this next level of detail.
    
    1. I agree that the semantics of the return values should be the same for
    the creation of persistent and transient entities.
    
    2. The idea of representing a stateless transient entity with a null handle
    is hanging around from the timeframe when the service end-point was the
    entity and the handle was only related to working around the stateless
    character of the current infrastructure. I doubt those semantics still work
    in the current model, but haven't thought through it yet.
    
    Your general point: There are proposals going forward at the WSDL level for
    stateful services. What I understand of the current proposals would not be
    inconsistent with the approach we are currently taking. Once that level of
    definition firms up, we definitely will need to revisit how Consumers
    interact with stateful WSIA/WSRP entities.
    
    
    
    
                          "Wilson, Kirk"
    
                          <Kirk.Wilson@ca.c        To:       Rich
    Thompson/Watson/IBM@IBMUS, wsia@lists.oasis-open.org,
                          om>                       wsrp@lists.oasis-open.org
    
                                                   cc:
    
                          06/08/2002 11:50         Subject:  RE: [wsia] [wsrp]
    [wsrp-wsia joint interfaces] Merged
                          AM                        interfaces     document
    
    
    
    
    
    
    
    Rich,
    
    
    I would like to raise a question or two on the Merged interfaces document.
    (By the way, I thought the document was much clearer than the previous
    document and answered several questions I had related to rev 0.44--revised
    signatures of set/getProperties removed some questions I had.  Section 2.1
    was especially helpful to us "general readers".)
    
    
    First, a comment: where an operation throws a fault message, I believe it
    is now standard to include that exception in the operation signature.
    
    
    The principal question concerns p.13 lines 2-3: "An entityHandle [for a
    transient entity] can be a null string, indicating that the requested
    entity is stateless."   Two points:
    
    
    1. In the case of persistent entities, a null return value indicates
    failure of creation.  Isn't the dual semantics of null return values going
    to cause confusion?  Assuming that creating an transient entity may in fact
    fail for some reason, how does one distinguish between failure of creation
    and having successfully created a stateless transient entity?
    
    
    2. What is a stateless transient entity (that doesn't even have a handle),
    anyway? I thought (based on the conf. call on Friday) that entities were
    like an instantiation of a Producer type which the Consumer wants to talk
    to.  But what's the purpose of a stateless transient entity if all that can
    be done with it is to create it?  Evidently, neither the Consumer nor
    Producer is going to be able to talk very much to this "thingy".  Is a
    stateless transient entity equivalent/related to in anyway to a stateless
    service?  It would seem not (nor would it seem to be necessary on the
    current model of stateless services-??).  I believe this question relates
    to an issue that was brought up at the very end of the conf. call on
    Friday:  What is the relationship between transience and statelessness?
    
    
    I also have a general question (stimulated by section 5.2), which I hope is
    not too naive.  WSIA compliant services can obviously be stateful and they
    can also be stateless.  There can also be certainly be stateless non-WSIA
    services, and I assume that there could also be stateful non-WSIA services
    that are perfectly legitimate.  This would seem to indicate that the
    specific standards for defining a stateful Web service should be
    independent of defining a WSIA service (or a WSRP service in particular).
    The WSIA (and WSRP) committees are defining a lot of what is required for
    stateful services (more or less out of necessity because there are no other
    standards for stateful services out there).  My questions are, Is/are any
    other committee(s) working on standards for stateful Web services?  (If so,
    shouldn't we be working with them on these groudwork issues?) Or, is it
    expected that the standards we define will be the candidate for industry
    acceptance?  (Anyone can answer.)
    
    
    Kirk Wilson
    Computer Associates
    Manager (Aion)
    Tele: 603-823-4023
    Fax:  603-823-4025
    mailto:kirk.wilson@ca.com