Good questions! Some thoughts below.
On 10/29/10 2:52 AM, Mike Edwards wrote:
Key differences that I see:
In some ways this seems to be a
to the "Global Unnamed Channel" that is in the
current spec. Can you explain the
When one of my astute co-workers pointed out that we didn't have
autowire for events, but we do for services, I started trying to
sketch out in my feeble brain what it might mean. From what I can
tell, it does seem to map to the use case that Oracle outlined at
the F2F. My take-away from their presentation was that references
to named "global" channels were really just an alias for "scoping"
or "intent", and that calling these channels was slightly confusing,
if only because a single "global" domain channel could map to many
underlying transport destinations.
- An explicit notion of "scoping"
- Not associating with a notion of a single modeled "channel",
when, in fact many underlying channels might be used.
- Where these autowire producers and consumers exist, I suspect
it is appropriate to automatically expose them as part of a
composite's componentType. This is different from autowire with
references, but I suspect appropriate.
However, there seems to be a
here of not using channels at all, which I'd like to
In nailing down the concrete details, that seems like one possible
outcome. Another could be that we require that deployers declare
channels that will "attach" to the "autowire" producers &
consumers before deployment succeeds.
Does this issue attempt to
means of connecting Producers and Consumers
without needing to explicitly
type="cite">Are the implied
completely determined by the
of each Producer and each Consumer, in
a pairwise fashion?
Perhaps, but as I suggest above, we could allow for enforcing
attachment to explicitly declared channels.
What are the implied rules for
some Producer and some Consumer?
Do the event type sets for each
to match exactly? Does the Consumer merely
have to have a subset of the
Those were some questions that occurred to me as well. One
possibility is exact matching. Seems like your suggestion of
consumers subsetting producers fits better.
Strategist - Emerging Technologies, SCA & SDO.
Co Chair OASIS SCA Assembly TC.
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Eric Johnson <firstname.lastname@example.org> wrote on
> [image removed]
> [sca-assembly] NEW ISSUE: Need an equivalent to
> eventing world
> Eric Johnson
> OASIS SCA Assembly
> 29/10/2010 00:43
> Title: Need an equivalent to "autowire" for the eventing
> Target: Assembly 1.2 WD 01
> With the references and services of SCA Assembly, the
> supports the notion of "autowire". Whatever the merits
in the service
> space, this concept fits even more naturally into the
> The use case: Forcing users to explicitly wire up all of
> and consumers may be over-determined. That, is, given
> specification of which events a consumer is interested
in, and the
> events that a producer sends out, that should be
sufficient to wire
> them. Making this situation worse, users might have to
> error prone effort of specifying which channels are
required to connect
> to which producers, and possibly missing out, or
> few cases.
> One distinction to draw in the "autowire" of producers
> the eventing world is that it may be very useful to have
> consumers and producers cross composite boundaries. Some
> "scope" might be appropriate. Two forms of scope
> - one bounded by the presence of a parent composite
> - the other tied to some notion of intent. For example,
> "sales", or "sales, northamerica", or "manufacturing,
> Abstract proposal:
> Add to a component producer, and a component consumer an
> @autowire (true/false). The presence of @autowire true
> of the @target, and @source attributes. Also add an
> attribute, which includes a space separated list of
> In conjunction with autowiring, a producer must declare
> events it produces, and a consumer must declare the exact
set it consumes.
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