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
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From:
Eric Johnson
<>
To:
Anish Karmarkar
<>
Cc:
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<>
>>>>> To: OASIS SCA
Assembly<>
>>>>> 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????].
>>>>>
>>>>>
>>>>>
>>>>>
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>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
------------------------------------------------------------------------
>>>>>
>>>>>
>>>>>
>>>>> /
>>>>> /
>>>>>
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>>>>> IBM United Kingdom Limited - Registered
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>>>>>
>>>>>
>>>
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