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Subject: Re: [sca-assembly] [Issue 253]: (1.2) Must a global domain channelbe deployed before it can be used?


<vdR>
My words weren't intended to be too similar to your original, but I certainly missed the question of the application composite being deployed containing the definition of an auto-deployed channel.  My apologies.  I don't see anything for an auto-deploying runtime to do in the case where the GDC is defined as part of what is being deployed.  But again, if the composite doesn't contain the GDC definition, we're back to either rejecting it or auto-deploying it, aren't we?  Am I missing something here?
</vdR>

We define three states for SCA: installed, deployed and running. We do not require error checking (such as whether a producer refers to a global channel that has been deployed or not) in the deployed state (but a runtime could). WRT whether we only have only two options: rejecting it or auto-deploying it when the composite doesn't contain the global channel definition -- we actually have three options. The third one being you allow the deployment but you don't run anything. Before you run anything, you require that all the expected deployments (including deployment of global channels through a separate composite) get done.

This problem is no different than references in a deployment composite that refer to services that happen to exist at the domain-level only through the deployment of a different composite.

-Anish
--

On 2/14/2011 4:21 PM, Danny van der Rijn wrote:
4D59C723.9030500@tibco.com" type="cite"> <vdR>.. responses like this ...</vdR>

On 2/14/2011 3:09 AM, Mike Edwards wrote:
OFDEC17CA4.C7EE16A9-ON80257837.003A9CF3-80257837.003C9AE1@uk.ibm.com" type="cite">
Danny,

Responses as  <mje>...</mje>

Yours, Mike


Dr Mike Edwards  Mail Point 146, Hursley Park
STSM  Winchester, Hants SO21 2JN
SCA & Services Standards  United Kingdom
Co-Chair OASIS SCA Assembly TC  
IBM Software Group  
Phone: +44-1962 818014  
Mobile: +44-7802-467431 (274097)  
e-mail: mike_edwards@uk.ibm.com  
 
 




From: Danny van der Rijn <dannyv@tibco.com>
To: Mike Edwards/UK/IBM@IBMGB
Cc: OASIS Assembly <sca-assembly@lists.oasis-open.org>
Date: 11/02/2011 19:33
Subject: Re: [sca-assembly] [Issue 253]: (1.2) Must a global domain channel be deployed before it can be used?







On 2/10/2011 2:48 AM, Mike Edwards wrote:


Danny,


I'm less about making arguments and more about trying to describe the Event Processing ideas in the same terms that we

have already described for services in the current V1.1 specifications.  There, the spec does describe different styles of

runtime, with differing approaches to deployment and to the possibility of redeployment.




Mike -

Let me rephrase my previous mail from "your arguments ... " to "your questions ...".  I didn't mean to appear argumentative by my lazy choice of words :-)

I tried to point out that auto-deployment carries an implication of redeployment, since if the runtime auto-deploys some channel
for which there is actually a concrete channel supplied by some later deployment, then we are inevitably into the realm of

redeployment.


Again, though, I don't see the questions being centered around auto-deployment, but about deployment and redeployment in general.  Imagine, for instance that in order to deploy some composite, I must first deploy a GDC (if we don't allow auto-deployment).  So I do so, but give it no configuration, or any configuration that isn't acceptable to a later deployment.  And I reword your statement slightly: "...
auto-deployment carries an implication of redeployment, since if the runtime  auto- administrator deploys some channel for which there is actually a concrete channel different configuration supplied by some later deployment, then we are inevitably into the realm of redeployment. "

<mje>
Your words don't mean anything like my original ones - you've avoided the question of how the simple case of my application composite containing
the definition of a Domain channel to deploy gets handled in the case of a runtime offering auto-deployment.
</mje>

<vdR>
My words weren't intended to be too similar to your original, but I certainly missed the question of the application composite being deployed containing the definition of an auto-deployed channel.  My apologies.  I don't see anything for an auto-deploying runtime to do in the case where the GDC is defined as part of what is being deployed.  But again, if the composite doesn't contain the GDC definition, we're back to either rejecting it or auto-deploying it, aren't we?  Am I missing something here?
</vdR>

OFDEC17CA4.C7EE16A9-ON80257837.003A9CF3-80257837.003C9AE1@uk.ibm.com" type="cite">
Redeployment of a channel is at the least a tricky thing.  The same can be said of the redeployment of a service component.

Basically, what happens to anything that is "in flight"?  I was trying to address some of these issues for auto-deploy channels in what I wrote.



I would say that GDC's don't have an analogue in the 1.1 specification in that the 1.1 specification allows and encourages fuller encapsulation.  With the current event processing drafts there is a large area where we're forcing components that wish to communicate outside of their component using SCA to do so using GDCs.  There is no way, for instance to assemble two components that communicate with each other into a self-contained, encapsulated composite.


<mje>
That you can make such a statement makes me feel that you have a very different understanding of SCA than I do.

For me, the assembly of 2 components that communicate with each other via a channel is "HelloWorld" level SCA 1.2.

I also don't understand the comment that "we're forcing components ... to do so using GDCs" - promotion is there for the support of controlled exposure of dependencies and this applies to both producers and consumers.

If your concern is with this statement in the current spec:  "An SCA runtime MAY support the use of private channels [ASM????]." ie non-Domain channels are optionally supported, then I suggest that you raise a very specific issue to deal with that.
</mje>

<vdR>
Can you explain your "HelloWorld" scenario?  Just to be sure that you understood my point, what I'm focusing on is the fact that I start with 2 components that are developed independently, then I assemble them into a composite that is both encapsulated, and self-contained.  In my mind that rules out any use of GDCs.  (i.e. my "forcing ... " comment as an option that I don't like.)  And since we don't have an answer for promotion a la 227, I'm not sure how to solve it at all, let alone with the triviality that you imply.  What kind of promotion are you using in your use case?  Perhaps it's promoting one producer and one consumer?  If so, how would you do that with channels instead? 

And no, I'm not talking about the private channels at all in this thread.
</vdR>

OFDEC17CA4.C7EE16A9-ON80257837.003A9CF3-80257837.003C9AE1@uk.ibm.com" type="cite">
 In 1.1, the redeployment question that you ask can be asked for the whole encapsulated composite as a whole, and can be answered in ways that are probably more self-consistent than what we can come up with for GDCs.  I understand that this is more of an argument against GDCs and/or an argument for resolution of 227 in a way that addresses this question.  I continually find myself butting up against that issue, yet we seem to have devolved into a pattern of ignoring the elephant in the room.  This week, this blind man grasps the 227 elephant by the tail and sees it as a 253 rope ...

<mje>
I simply don't follow.
</mje>


<vdR>
Let me take another stab here.  You were asking about redeployment.  If what you're redeploying is completely encapsulated, then an implementer could imagine various scenarios that are all defensible - all in-flight messages are preserved;  all in-flight messages are lost; etc. 

I agree with you that redeployment of GDCs poses a sticky problem.  My answer to that is to use GDCs less, or delete them entirely.  If we could solve 227, I would find myself FAR less likely to want to use GDCs.  That was the point I was trying to make, albeit a bit obliquely.  My apologies for that.

Regardeless of what happens with 227, I don't see how adding this other use case where GDCs could be redeployed puts the onus of solving the redeployment problem on that new use case.  That seems to me to be your argument.
</vdR>

OFDEC17CA4.C7EE16A9-ON80257837.003A9CF3-80257837.003C9AE1@uk.ibm.com" type="cite"> Now, let me make my position clear on "auto deployment".  I think that we have similar behaviour applied in particular to PolicySets,
with the notion that in principle an SCA Runtime can have other mechanisms to supply these things to the Domain, other than by

deploying the contents of one or more Contributions.  eg there is the concept of PolicySets being deployed from some kind of

Repository and not necessarily being held in any application Contribution.  The current specs don't disallow this, although they

deliberately don't say much about it since the possibilities for implementation are very broad and there is little normative to say.

What it is - is outside the standards.


While I see some analogy here, and agree with it, the presence of a reference channel is somewhat more intrinsic to operation than the presence of a PolicySet is, so I feel much less comfortable being vague about it.  Clarity is necessary here, whether it is to explicitly allow or explicity disallow auto-deployment and/or define what the behavior is in the absence of a referenced GDC.


So, I could envisage auto-deployment along the same lines.  Something that any SCA Runtime could choose to provide by some

means, but where the SCA specifications say very little.  If an SCA runtime chooses to provide auto-deployment, then it can do so

in any way it wishes.


I agree that it would be an implementation decision as to how to do it.  I would support a proposal that uses different RFC language from the initial proposal in the JIRA.  Something along the lines of


When contributing artifacts to a domain that contain references to global domain channels that have not been previously deployed, the SCA runtime MAY reject such contributions.  Alternatively, the SCA runtime MAY automatically create and deploy said global domain channels in this situation.




The downside for an application developer is that their application, as contained in a set of Contributions, may not work on some SCA

runtimes, if the developer/assembler chooses not to contain one or more Domain Channels within their composites, that they rely on

in some components within the application.  If they do this, then their application may work fine on an SCA runtime that supports

auto-creation but fail when run with a runtime that does not support auto-creation.  The same is true, I note, of PolicySets - if the

application does not supply them, there is no guarantee that they will be made available through some other mechanism by the

SCA runtime.


See my earlier comment on the analogue to policySets.  I would also point out that the "defensive" manuever of including the GDC in the composite may well backfire if the GDC already exists in the domain.  Are we left with another issue along the lines of do we allow deployment of "compatible" configurations of GDCs??



However, for any SCA Runtime that DOES provide auto-creation, there is a need to describe what happens if, due to the sequence of

deployments, some auto-created channel is "replaced" by the later deployment of a "real channel".  In my opinion, it would be wise to

try to avoid such a situation.  However, I don't see a way of preventing this situation - perhaps this is something that you'd like to describe.



To answer whether the auto-deployed channel is any less "real" than something else, I would offer that it doesn't matter to the runtime where the contribution came from.  So if you would find it more clear to define auto-deployment as the process of the runtime synthesizing a piece of contribution and deploying it, I would not object to that.


<mje>
An auto-deployed channel would be just as real as anything else, but you seem to be sliding away from my point - IF a channel were auto-deployed but my application happened to consist of multiple
separately deployed contributions and just happened to contain the definition of the Domain channel in a contribution that is deployed later, then what happens?

How does the deployer distinguish this case?
</mje>

<vdR>
I think I'm starting to see what I couldn't divine before - your use case seems to be not that the GDC is deployed 2 weeks after the composite in which it is used, as I had thought.  Your use case is that the GDC is deployed 30 seconds after?  Is that it?

In that case, you have a problem no matter what.  There is going to have to be *something* done by the runtime to the first composite.  Either the runtime should reject its deployment, the runtime should ask "Do you have a GDC definition in your pocket that I could deploy before I (finish) deploy(ing) this one?" it could auto-deploy one and fail/redeploy later, etc.  There are many possibilities.  But again, I don't see how auto-deployment *creates* this problem.  It is possible that it exacerbates it, I agree.  But if that's what you're worried about, then let's answer that in the context of an issue around that, rather than in this issue.
</vdR>


OFDEC17CA4.C7EE16A9-ON80257837.003A9CF3-80257837.003C9AE1@uk.ibm.com" type="cite">
Redeployment is something that we must describe in general for all of SCA.  


<mje>
OK, in that case, would you care to describe the redeployment of a Channel and its implications?

So far I have noted that auto-creation implies redeployment.  One reason I'm not in favour of auto-deployment is BECAUSE of this redeployment implication and its consequences.
If you can show that redeployment of a channel is a breeze, then perhaps some of my concerns will go away.
</mje>


<vdR>
I'm fine with the idea of deleting GDCs from the draft.  That would go a long way to dealing with your redeployment issues.  I imagine that idea wouldn't go over well, though ;-) 

I disagree with what you note.  Auto-creation does not imply redeployment.  Sure, redeployment can follow auto-creation, but redeployment is not required.  If redeployment is your bugbear, then let's have an issue about that, and not think that a spec without auto-creation doesn't require dealing with redeployment.
</vdR>

OFDEC17CA4.C7EE16A9-ON80257837.003A9CF3-80257837.003C9AE1@uk.ibm.com" type="cite">Absent that, I don't see any need to describe this isolated case.  Again, I would see the auto-deployment as shorthand for deploying a GDC with the required name and no other configuration.  Assuming that it is deployed, later deployment of a channel with the same name would simply follow our redeployment rules.  If we choose to leave the spec silent on redeployment, we haven't made the issue any worse by allowing auto-deployment, as redeploying a channel that was previously auto-deployed would be exactly as implementation-defined as any other redeployment - no more, no less.

Danny


Yours, Mike


Dr Mike Edwards  Mail Point 146, Hursley Park
STSM  Winchester, Hants SO21 2JN
SCA & Services Standards  United Kingdom
Co-Chair OASIS SCA Assembly TC  
IBM Software Group  
Phone: +44-1962 818014  
Mobile: +44-7802-467431 (274097)  
e-mail: mike_edwards@uk.ibm.com  
 
 




From: Danny van der Rijn <dannyv@tibco.com>
To: Mike Edwards/UK/IBM@IBMGB
Cc: OASIS Assembly <sca-assembly@lists.oasis-open.org>
Date: 09/02/2011 17:34
Subject: Re: [sca-assembly] [Issue 253]: (1.2) Must a global domain channel be deployed before it can be used?






Mike -

Your arguments seem to me to be more arguing against case a) than against autocreation, as they hold for *any* more restrictive redeployment, not just one whose previously deployed state was perhaps auto-deployed.

Auto-deployment (as I envision it) is merely shorthand for an actual deployment. ("Your composite references a global domain channel that hasn't been deployed.  Shall I create one for you and deploy it, or would you prefer me to reject deployment of your composite outright?")  Your arguments just point out another weakness I see in the concept of global domain channels.

Danny

On 2/9/2011 2:45 AM, Mike Edwards wrote:


Danny,


SCA Runtime "styles";


a) Reconfiguration/Redeployment is allowed

b) Reconfiguration/Redeployment is not allowed


Case b) is the simpler of the two.  In this case, all the configuration must be present when the runtime is started.

Either Domain channels are part of the configuration at this point or not - if not, then any references to Domain

channels would either be errors (no auto-creation of channels) or would require auto-creation of channels.


Case a) is the case where there can be separate deployment of (some) consumers & producers and of the

channel(s) that they connect to.  I note that this can only happen for Domain level channels.  Once separate

deployment is possible, then the timing of deployment matters - if Channel deployment is later than deployment

of any of the producers that connect to the channel, then it the question of auto-creation comes into play.

If no auto-creation is NOT allowed by the runtime, then any event produced will have nowhere to go, which might

be flagged as an error (since the producer is configured to transmit the events).  If auto-creation is allowed, then

the events will be flowed to an auto-created Channel and on to whatever consumers are connected to that channel.


When the Channels are later deployed into such a runtime, I assume that the auto-created Channels get "replaced"

by the deployed versions, with whatever configuration they carry.  Since the configuration may carry Filters, this may

mean that some events get forwarded by the auto-created channel that don't get forwarded by the specifically

deployed channel.  I'm not sure what this would mean for the consumers attached to the channel.  More problematic

would be any binding and policy information attached - the binding could indicate the need to have the channel use

some specific existing infrastructure (eg some MQ queue) - and if the intention is that events flow to/from the existing

infrastructure, then the auto-deploy channel is unlikely to do this.  


I think the result of this is that during the period when any auto-deploy channels are being used, before the point
where the specifically configured channels are active, that some events may not reach all their intended destination(s)

and some events may not be received by some SCA consumers listening on those channels.


All of which might argue for a process of deploying the Domain channels first, which kind of undermines the idea of

auto-deploying those channels.




Yours, Mike


Dr Mike Edwards  Mail Point 146, Hursley Park
STSM  Winchester, Hants SO21 2JN
SCA & Services Standards  United Kingdom
Co-Chair OASIS SCA Assembly TC  
IBM Software Group  
Phone: +44-1962 818014  
Mobile: +44-7802-467431 (274097)  
e-mail: mike_edwards@uk.ibm.com  
 
 




From: Danny van der Rijn <dannyv@tibco.com>
To: Mike Edwards/UK/IBM@IBMGB
Cc: sca-assembly@lists.oasis-open.org
Date: 08/02/2011 22:02
Subject: Re: [sca-assembly] [Issue 253]: (1.2) Must a global domain channel be deployed before it can be used?







OK, I'll take a stab at answering your question, although I'm just presenting one alternative among many.

First, though, your wording interests me:


in the case where the channel concerned DOES

have configuration and it so happens that the channel is deployed to the Domain some time after some of the

producers and consumers using the channel are deployed to the Domain.



What intrigues me is the notion that your use case allows you to assert that something about the channel's configuration.  Can that configuration never change?  If so, how would you deal with changing that?  By undeploying and redeploying it?   Some other means?

I would apply whatever answer you have to that question to this one.

To wit:

Say that you do allow some form of runtime redeployment or modification.  So in this case the implementation MAY autodeploy the channel (RFC 2119 wording intentional).  If someone chooses to redeploy the channel with further configuration later, so be it.  Use whatever form of modification you were going to support in the case where the prior configuration was not auto-deployed.

Say you don't allow modification.  Then I'd say that your implementation should either not allow for autodeployment, or that your implementation should put up some reasonable bar to autodeployment.

Danny

On 2/8/2011 1:51 AM, Mike Edwards wrote:


Folks,


I'd appreciate it if someone could explain how things would work in the case where the channel concerned DOES

have configuration and it so happens that the channel is deployed to the Domain some time after some of the

producers and consumers using the channel are deployed to the Domain.



Yours, Mike


Dr Mike Edwards  Mail Point 146, Hursley Park
STSM  Winchester, Hants SO21 2JN
SCA & Services Standards  United Kingdom
Co-Chair OASIS SCA Assembly TC  
IBM Software Group  
Phone: +44-1962 818014  
Mobile: +44-7802-467431 (274097)  
e-mail: mike_edwards@uk.ibm.com  
 
 




From: Anish Karmarkar <Anish.Karmarkar@oracle.com>
To: sca-assembly@lists.oasis-open.org
Date: 08/02/2011 09:15
Subject: Re: [sca-assembly] [Issue 253]: (1.2) Must a global domain channel be deployed before it can be used?








Danny and Eric's arguments have convinced me that auto-creation of
global channels make sense. It would certainly simplify config/deploy --
I won't have to create a separate composite that contains only the
channel name and then deploy it to the domain. Currently we do allow
this for the default channel ("//"). As Eric points out, my issue wrt
error detection can be dealt with by tools (I can have a global option
or flag for the deployer). Given that we already allow this for the
default channel, and channels currently require no additional
configuration (one can have configuration, but is not required to),
autocreation would provide a consistent model and would make simple
deployment scenarios easier.

-Anish
--

On 2/7/2011 9:50 AM, Eric Johnson wrote:
>   To be more explicit, and echo Danny's point, I think we have four options:
>
> 1) Mandate that auto-creation of channels works
> 2) Mandate that auto-creation of channels never works
> 3) Identify specific situations where #1 or #2 are possible
> 4) Take no position (this may still imply changes to the spec, insofar
> as we highlight the point, while taking no sides)
>
> I raised the issue because #4, it seems to me, leaves the door open for
> interoperability failures. ("I deployed X over here with no problems,
> but it doesn't work over there.")
>
> Insofar as I've recall the discussion of the concrete use cases for
> global domain channels (Oracle's F2F presentation), we explicitly noted:
> no filters, no policies, and no bindings on said channels. Meaning,
> configuration optional, and it's just a name. If it is just a name, why
> can't I auto-create?
>
> Anish notes that some people like the safety net of predefined names,
> and I agree that's useful. However, that can be addressed in a variety
> of ways that aren't nearly so heavy-handed as to simply deny the
> deployment. ("The domain contribution includes references to global
> domain channel "foo" that doesn't yet exist. Continue/Cancel?).
>
> -Eric.
>
> On 2/7/11 9:30 AM, Danny van der Rijn wrote:
>> Yet all their configuration is optional?
>>
>> On 2/7/2011 3:39 AM, Mike Edwards wrote:
>>>
>>> Eric,
>>>
>>> My view is that global channels - indeed any channels - are more than
>>> a name - they have configuration associated
>>> with them. A system which does not require them to be declared makes
>>> it difficult to provide required configuration.
>>>
>>> Yours, Mike
>>> ------------------------------------------------------------------------
>>>
>>> Dr Mike Edwards                  Mail Point 146, Hursley Park                  
>>> STSM                  Winchester, Hants SO21 2JN
>>> SCA & Services Standards                  United Kingdom
>>> Co-Chair OASIS SCA Assembly TC                                  
>>> IBM Software Group                                  
>>> Phone:                  +44-1962 818014                                  
>>> Mobile:                  +44-7802-467431 (274097)                                  
>>> e-mail:                  
mike_edwards@uk.ibm.com                                  
>>>
>>>
>>>
>>>
>>>
>>> From:                  Eric Johnson
<eric@tibco.com>
>>> To:                  Anish Karmarkar
<Anish.Karmarkar@oracle.com>
>>> Cc:                  
sca-assembly@lists.oasis-open.org
>>> Date:                  04/02/2011 17:14
>>> Subject:                  Re: [sca-assembly] [Issue 253]: (1.2) Must a global domain
>>> channel be deployed before it can be used?
>>>
>>>
>>> ------------------------------------------------------------------------
>>>
>>>
>>>
>>>
>>> On 2/4/11 1:37 AM, Anish Karmarkar wrote:
>>> > I don't see this being different than say requiring that a variable be
>>> > declared before it is used.
>>> <eej>
>>> Which might be a perfect analogy.
>>>
>>> If the only point of a global channel is to establish a name, then
>>> there's actually minimal value to declaring it before it is used. Many
>>> dynamic languages work this way - Python & Ruby. In the case of global
>>> domain channels, for many use cases, filters and bindings don't make
>>> sense, so the channel just becomes a name. At which point, declaration
>>> before use looks like ceremony over substance.
>>>
>>> </eej>
>>> >
>>> > -Anish
>>> > --
>>> >
>>> > On 2/1/2011 10:11 AM, Danny van der Rijn wrote:
>>> >> An interesting argument for tight coupling...
>>> >>
>>> >> On 2/1/2011 6:19 AM, Anish Karmarkar wrote:
>>> >>> I think this is a fine issue to raise, but I don't quite support the
>>> >>> auto-creation proposal. The only global channel that is
>>> >>> 'auto-deployed' or always exists is the default channel.
>>> >>>
>>> >>> I would want the runtime to tell me if I referenced a channel
>>> that has
>>> >>> not been deployed (unless it is the default channel, which is the
>>> >>> exception). If I want a producer and consumer (especially if they are
>>> >>> in different composites) to communicate over a common channel, I
>>> would
>>> >>> want the system to catch typos. For example, if the producer is
>>> >>> connected to the channel "//omg" and the consumer is connected to
>>> >>> "//zomg", they would be deployed fine but my application would not
>>> >>> work correctly.
>>> >>>
>>> >>> -Anish
>>> >>> --
>>> >>>
>>> >>> On 1/31/2011 10:19 AM, Eric Johnson wrote:
>>> >>>> Hi Peter,
>>> >>>>
>>> >>>> On 1/31/11 10:02 AM, Peter Niblett wrote:
>>> >>>>> Eric
>>> >>>>>
>>> >>>>> You said..
>>> >>>>>
>>> >>>>> Neither of the above indicate whether or not the global domain
>>> >>>>> channel
>>> >>>>> can be used before it is referenced.
>>> >>>>
>>> >>>> Ah yes, the joys of a muddled brain on Monday morning. You're
>>> >>>> correct -
>>> >>>> the question is whether or not the global domain channel can be used
>>> >>>> before it is *created* via a contribution.
>>> >>>>
>>> >>>> Thanks for catching my circularity.
>>> >>>>
>>> >>>> -Eric.
>>> >>>>>
>>> >>>>> I'm not sure how you can "use" a channel without referencing it (I
>>> >>>>> assume "reference" means "wire to/from"), but I think the question
>>> >>>>> you
>>> >>>>> are asking is the one in the title - "can you reference a channel
>>> >>>>> that
>>> >>>>> hasn't been defined to the SCA assembly?". I think this is one
>>> place
>>> >>>>> where the current spec is clear.. you can't reference a domain
>>> >>>>> channel
>>> >>>>> that hasn't been defined.
>>> >>>>>
>>> >>>>> So it looks as though your issue is to say that we should
>>> change the
>>> >>>>> spec to say that it permits (in fact requires) autocreation of
>>> domain
>>> >>>>> channels. Presumably these channels would have to be created with
>>> >>>>> default attributes (though I know you think they shouldn't have
>>> >>>>> attributes at all).
>>> >>>>>
>>> >>>>> Regards
>>> >>>>>
>>> >>>>> Peter Niblett
>>> >>>>> IBM Senior Technical Staff Member
>>> >>>>> Member of the IBM Academy of Technology
>>> >>>>> +44 1962 815055
>>> >>>>> +44 7825 657662 (mobile)
>>> >>>>>
>>> >>>>>
>>> >>>>>
>>> >>>>>
>>> >>>>> From: Eric Johnson
<eric@tibco.com>
>>> >>>>> To: OASIS SCA Assembly
<sca-assembly@lists.oasis-open.org>
>>> >>>>> Date: 31/01/2011 17:19
>>> >>>>> Subject: [sca-assembly] NEW ISSUE: (1.2) Must a global domain
>>> channel
>>> >>>>> be deployed before it can be used?
>>> >>>>>
>>> ------------------------------------------------------------------------
>>> >>>>>
>>> >>>>>
>>> >>>>>
>>> >>>>>
>>> >>>>>
>>> >>>>> Title: Must a global domain channel be deployed before it can be
>>> >>>>> used?
>>> >>>>>
>>> >>>>> Target: Assembly 1.2 WD 03
>>> >>>>>
>>> >>>>> Description:
>>> >>>>>
>>> >>>>> Via the "@target" and "@source" attributes defined on a consumer&
>>> >>>>> producer, the assembler can reference global domain channels.
>>> >>>>>
>>> >>>>> In section 5.8, the presumed to be normative text reads "SCA
>>> runtimes
>>> >>>>> MUST support the use of domain channels [ASM????]." That is
>>> followed
>>> >>>>> by:
>>> >>>>>
>>> >>>>> "To create a Domain Channel, deploy a composite containing a
>>> channel
>>> >>>>> directly to the SCA Domain (i.e., do not use that composite as the
>>> >>>>> implementation of some component in the Domain)."
>>> >>>>>
>>> >>>>> Neither of the above indicate whether or not the global domain
>>> >>>>> channel
>>> >>>>> can be used before it is referenced.
>>> >>>>>
>>> >>>>> Proposal:
>>> >>>>>
>>> >>>>> General theme: do not require the global domain channel to exist
>>> >>>>> before
>>> >>>>> it can be used.
>>> >>>>>
>>> >>>>> Specific text (needs refinement?):
>>> >>>>>
>>> >>>>> In section 5.8, Paragraph #2, append:
>>> >>>>>
>>> >>>>> When contributing artifacts to a domain that contain references to
>>> >>>>> global domain channels that have not been created, the SCA runtime
>>> >>>>> MUST
>>> >>>>> automatically create said global domain channels, and cannot reject
>>> >>>>> such
>>> >>>>> contributions [ASM????].
>>> >>>>>
>>> >>>>>
>>> >>>>>
>>> >>>>>
>>> ---------------------------------------------------------------------
>>> >>>>> To unsubscribe from this mail list, you must leave the OASIS TC
>>> that
>>> >>>>> generates this mail. Follow this link to all your TCs in OASIS at:
>>> >>>>>
>>>
https://www.oasis-open.org/apps/org/workgroup/portal/my_workgroups.php
>>> >>>>>
>>> >>>>>
>>> >>>>>
>>> >>>>>
>>> >>>>>
>>> >>>>>
>>> >>>>>
>>> ------------------------------------------------------------------------
>>> >>>>>
>>> >>>>>
>>> >>>>>
>>> >>>>> /
>>> >>>>> /
>>> >>>>>
>>> >>>>> /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/
>>> >>>>>
>>> >>>>>
>>> >>>>>
>>> >>>>>
>>> >>>>>
>>> >>>>>
>>> >>>
>>> >>> ---------------------------------------------------------------------
>>> >>> To unsubscribe from this mail list, you must leave the OASIS TC that
>>> >>> generates this mail. Follow this link to all your TCs in OASIS at:
>>> >>>
>>>
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>>> >>
>>> >
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>>> >
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>>>
>>>
>>>
>>> ------------------------------------------------------------------------
>>>
>>> /
>>> /
>>>
>>> /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/
>>>
>>>
>>>
>>>
>>>
>>>

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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









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








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