I'd think the third paragraph (with a few edits) expresses an important point that isn't covered elsewhere.
Formally, capabilities are found by a service consumer because they are currently, or will become visible. The visibility may be through a description of the capability (where access by means of a service would be included in the description) or a service description (where the real world effects imply the underlying capabilities.) But how does a given SOA decide what capabilities are needed? [not sure if "SOA deciding" is the way I'd phrase it.] Some parts of a SOA are capability-driven because an organization has certain capabilities that it wishes to expose. Other parts are need-driven because an organization has certain needs, and wishes to make those visible in order to find those organizations that have, or are willing to build, services that meet those needs. Need-driven capabilities might be built specifically for a given situation, or they might be dynamically created.
In thinking about the fourth paragraph, should we note that a big part of bringing needs and capabilities together in an SOA requires aligning policies and resolving policy differences?
Finally, in looking at what it means for a need to be satisfied by a capability, satisfying is not built on expectations of effect but on actual RWEs. I chose a capability based on expectations but my satisfaction is how well the RWEs meet those expectations.
Ken
On Jul 1, 2006, at 12:47 AM, Danny Thornton wrote:
As I look at the different sections of the RA
architecture, I like to ask myself how this helps me
move to a more concrete architecture. The "Needs and
Capabilities" section contains references to
visibility in the SOA, discussion of contracts and
possible Service Level Agreements, references the
execution context, references semantics, discussion
of the measurability of needs and capabilities and
expectations.
http://wiki.oasis-open.org/soa-rm/TheArchitecture/NeedsAndCapabilities
I do not believe that measurability of needs,
capabilities, and expectations are discussed in other
sections of the RA so I find this to be one of the key
discussion points for this section. Frank discussed
measuring the need in terms of a proposition against
the shared state and the use of policies in that
measurability.
Also, the point about an enterprise SOA having
policies and an internet SOA having contracts (I would
also add policies) was a good point to bring out.
Danny
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Ken Laskey
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