Hi,
Two thoughts here:
As per our proposed (but not yet adopted) issues process, issues are not
supposed to be discussed until accepted - except insofar as the
discussion is towards whether they should be accepted.
Second, it looks to me like the email below is digging into a separate
issue. And I cannot quite figure out whether it is coupled to ISSUE #2,
or genuinely separate. If separate, as issues ed., I'd love to see a
separate issue filed....
-Eric.
Peshev, Peter wrote:
> Hi
>
> When speaking about redirecting the callback, by API it is possible to
> redirect it to another component, whose services could be lacking
> binding.ws and instead having only some other binding /*let's say
> binding.jms due to the current lack of other bindings in the OASIS TC :)
> */.
>
> If that should be a supported scenario (outbound one binding, inbound
> another) that looks that the callbackId-s should be something SCA
> specific, and hardly rely on some WS-standard. I am little bit confused
> in which TC (java, assembly, bindings) that should be addressed.
>
> Any thoughts / comments?
>
> Btw, I personally dislike refirecting the callback since that is
> actually dynamic appearance of wires (invocation paths) via java code
> usage.
>
> That introduces hidden dependencies among components, which cannot be
> analyzed and displayed by any tooling (except some heuristic code
> parsing), cannot be overridden by the assembler via SCDL files and
> somewhat hinders the main focus of component reuse and SOA. In addition
> such dynamic redirecting is likely to complicate any implementation
> which spans beyond one JVM.
>
>
> Best Regards
> Peter
>
>
> -----Original Message-----
> From: Simon Nash [mailto:]
> Sent: Tuesday, 2. October 2007 13:51
> To:
> Subject: Re: [sca-bindings] ISSUE 2 - Callback support over the Web
> Service binding
>
> Using the wsa:ReplyTo header for the callback endpoint does not seem to
> exactly match SCA callback semantics, which allow callback messages to
> be
> directed to a different endpoint from the endpoint that receives the
> reply
> to the original request (by calling setCallbackObject() with a
> ServiceReference). Using wsa:ReplyTo also requires a message ID to be
> added to the original request and the same message ID to be returned on
> the reply and any callbacks in the wsa:RelatesTo header. This is more
> of
> an observation than a problem, though it does require extra state to be
> maintained for the message IDs being exchanged.
>
> In Tuscany, we did not use wsa:Reply To. Instead we used the
> WS-Addressing wsa:To endpoint reference with reference parameters to
> represent the callback endpoint (as a wsa:EndpointReference), the
> callback
> ID, and the conversation ID for stateful callbacks.
>
> I did not propose a specific solution when opening this issue because I
> wanted to open this up to as many suggestions and options as possible.
> The
> discussion around wsa:ReplyTo has been interesting. Perhaps someone
> will
> have an idea on we can overcome the semantic mismatch that I mentioned
> above. I agree that defining a new header for SCA callbacks would be
> undesirable. Even the use of SCA-specific reference parameters seems
> less
> than ideal, but without them I'm not sure how additional information
> like
> the callback ID could be transmitted. We can't use wsa:MessageID for
> this, because of the statement in the WS-Addressing spec that "No two
> messages with a distinct application intent may share a [message id]
> property." Perhaps the callback ID could be mapped into a wsa:MessageID
>
> by adding a unique discriminator, so different callback requests could
> use
> distinct message IDs from which the same callback ID could be extracted.
>
> Simon
>
> Simon C. Nash, IBM Distinguished Engineer
> Member of the IBM Academy of Technology
> Tel. +44-1962-815156 Fax +44-1962-818999
>
>
>
> Khanderao Kand <>
> 01/10/2007 22:47
>
> To
> Michael Rowley <>
> cc
>
> Subject
> Re: [sca-bindings] ISSUE 2 - Callback support over the Web Service
> binding
>
>
>
>
>
>
> Michael Rowley wrote:
>
>> One problem with using WS-Addressing wsa:ReplyTo is that it is usually
>> used to send the response message of a request/response pair. I don't
>> think that WS-Address forbids its use for subsequent messages
>> (callbacks), but it would at least be unconventional.
>>
>>
> [khanderao] IMHO WS-Addressing does not make any assumptions on the
> number of returned messages. It is upto the integration scenario to have
>
> one or many.
>
>> However, if we can't use wsa:ReplyTo, that would seem to imply that we
>> have to devise our own header to use, but that would be getting
>> dangerously close to inventing a wire-level protocol, which we don't
>> want to be doing.
>>
>>
> [khanderao] Introducing SCA specific correlation / replyTo parameters
> would not be essential. As far as possible we should be using the
> available standards, like WSA / WS-Coordination etc..
>
>> Michael
>>
>> -----Original Message-----
>> From: Eric Johnson [mailto:]
>> Sent: Monday, October 01, 2007 12:16 PM
>> To:
>> Subject: Re: [sca-bindings] NEW ISSUE: Callback support over the Web
>> Service binding
>>
>> Created as: http://www.osoa.org/jira/browse/BINDINGS-2
>>
>> -Eric.
>>
>> Simon Nash wrote:
>>
>>
>>> TARGET:
>>>
>>> Web Service Binding specification, section TBD
>>>
>>> DESCRIPTION:
>>>
>>> The Web Service binding provides no example or suggestion for how SCA
>>>
>
>
>>> callback semantics could be carried over Web services. There is an
>>> example in section 2.2.3 for how conversation semantics could be
>>> supported. It would be good to give some guidance (somewhere in the
>>>
>>>
>> range
>>
>>
>>> between example and normative) for what could be done for callbacks.
>>>
>>>
>> One
>>
>>
>>> possibility is to make use of the capabilities provided by
>>>
>>>
>> WS-Addressing.
>>
>>
>>> PROPOSAL:
>>>
>>> None yet.
>>>
>>>
>>>
>>>
>>>
>>>
>>> Unless stated otherwise above:
>>> IBM United Kingdom Limited - Registered in England and Wales with
>>>
>>>
>> number
>>
>>
>>> 741598.
>>> Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire
>>>
> PO6
>
>> 3AU
>>
>>
>>>
>>>
>>>
>>>
>>>
>
>
>
>
>
>
>
>
> Unless stated otherwise above:
> IBM United Kingdom Limited - Registered in England and Wales with number
>
> 741598.
> Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6
> 3AU
>
>
>
>
>
>
>
