<eej>We could, of course, also make my
proposal work for either atomic or composite components. Based on
what I've said, to satisfy the same requirements, my proposal - at
least in some scenarios - pushes less data into the componentType
for a component, but otherwise, it is exactly the same set of data
expressed in a different syntax.
...
</eej>
I would like to understand how your proposal would work for the
atomic component. IIRC, your proposal provided some sort of
'default' channel if none is injected. This would require an
atomic component to provide a channel implementation.
-Anish
--
On 11/23/2010 11:34 AM, Eric Johnson wrote:
4CEC1734.5060309@tibco.com" type="cite">
HI Mike,
Well, that does seem like progress. Hopefully Anish can chime in
with what he meant to end up in the componentType, and I can try
to pull together a proposal from that.
More thoughts below:
On 11/23/10 1:13 AM, Mike Edwards wrote:
OFFE950B21.5B13EF69-ON802577E4.0031AFB1-802577E4.003233CD@uk.ibm.com"
type="cite">
Folks,
Comments inline as <mje>.../mje>
Yours, Mike
Trying to pull the threads together on this
discussion. I'm going to run with the point I made in one of
my emails - just what, exactly, are we exposing in the
componentType when attempting to resolve 227?
Three proposed approaches, and their effect:
Eric: "Injected" channels, wherein componentType exposes a new
element for the injectedChannel. This effectively exposes the
filters, events, policies of the consumers and producers
connected to the "injected" channel.
Mike: Continue to promote the consumers and producers, and
then tie them together with a notion of "groupID". In effect,
this exposes the filters, events, policies of the consumers
and producers and groups them for channel wiring purposes.
Anish: "Prosumer" which promotes the a combination of
consumers and producers.
Writ-large, I think all of the above are introducing the exact
same set of information into the componentType, with subtle
variations in intended meaning.
Mike's proposal compares to mine in that where I would not
promote the consumers/producers tied to the injected channel,
but then indicate some of the key metadata about the
consumers/producers wired to the channel-to-be-injected,
Mike's proposal would promote them, and then tie them together
with groupID. Key differences here:
- Producers and consumers that could
otherwise be "hidden" in the injected channel approach are
now also available for independent wiring
- No new element introduced into
componentType
- No implication of anything actually being
wired - although when it is, there's a guarantee of being
wired to the same thing
<mje>
In my opinion,
the idea of marking producers and consumers in the
componentType as belonging to the same "group" has the
advantage of working
for any kind of
implementation - atomic or composite. I am not sure how to
describe an "injected channel" when dealing with an atomic
implementation.
</mje>
<eej>We could, of course, also make my
proposal work for either atomic or composite components. Based
on what I've said, to satisfy the same requirements, my proposal
- at least in some scenarios - pushes less data into the
componentType for a component, but otherwise, it is exactly the
same set of data expressed in a different syntax.
So I don't understand your point about not
being sure how to describe the meaning of an "injected channel"
- it is the exact same notion - a bunch of producers and
consumers grouped together under an identity. How you want to
think about that is (mostly) a matter of interpretation.
In any event, as a reminder, going back to my "channel scenarios
5" PDF (http://lists.oasis-open.org/archives/sca-assembly/201008/msg00006.html),
I think I show something of how this might be diagrammed as per
the picture on the top of page 4.
I don't see the value of allowing the same group ID on more than
one "consumer" and "producer" declared in the composite - those
elements already have the ability to roll up any number of
consumers/producers from the contained components. So one
aspect of the groupID notion that concerns me is that it adds an
additional axis of grouping that's just confusing. I mention
this, only because the diagram I mention above doesn't quite
capture the notion that multiple consumers could be promoted to
different promotion points and yet share a single group ID. So
for further discussion should note this distinction between the
picture I referenced, and this aspect of the group ID.
</eej>
OFFE950B21.5B13EF69-ON802577E4.0031AFB1-802577E4.003233CD@uk.ibm.com"
type="cite">
Anish's proposal differs from mine in terminology, and in
intent. Where I would have the injected channel *always*
provided, Anish's proposal would defer the wiring question to
the composer of the containing composite. Unclear to me - at
least from Anish's latest email [1], is whether or not he sees
the same information being in the componentType that
apparently Mike and I do. That is, Anish's email documents
the change to the composite, not how it reflects in the
componentType. It is unclear from Anish's proposal (at least
to me) whether or not the promoted producers & consumers
are available for separate wiring.
There's also a different pattern reflected in Anish and Mike's
proposals - where the "injected channels" approach defines a
1-to-M mapping between a channel defined by a surrounding
composite, and the producers/consumers wired to it, the
proposals from Mike and Anish instead define a M-to-N
relationship between the channels of the surrounding
composite, and the producers/consumers of the contained
component.
Steps forward:
1) Anish, can you provide a description of what you think ends
up in the componentType in your prosumer model?
2) If we pursue an approach like Anish and Mike's does anyone
have any feedback on a policy intent notion like "must-wire",
so that an inner composite can force that its
consumers/producers are wired up? This approach would then be
a functional superset of my injected channels approach.
<mje>
The issue of
cardinality, dealt with in ASSEMBLY-251, addresses the
question of "must wire" - in that issue a cardinality of
1..1 implies - "this producer/consumer MUST be connected to
one and ONLY one channel"
The reason to
raise that issue and to separate it from 227 is that
cardinality seems independent of the notion of requiring
some set of producers and consumers to use the SAME channel.
</mje>
<eej> Thanks for pointing that out. I
had overlooked ASSEMBLY-251 for some reason. </eej>
OFFE950B21.5B13EF69-ON802577E4.0031AFB1-802577E4.003233CD@uk.ibm.com"
type="cite"> Did I miss any differences?
-Eric.
[1] http://lists.oasis-open.org/archives/sca-assembly/201011/msg00038.html
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