I know we're trying to avoid
"+1"'s as much as possible on this list, so I will put it into words: I
completely agree with Duane on all his points just below.
Duane, I'm glad you've started your guide
to concept maps - hopefully in time this will help the situation. We have used
concept maps for the DRM as well.
Joe
From: Duane Nickull
[mailto:]
Sent: Thu 12/8/2005 1:40 AM
To:
Metz Rebekah; Bashioum, Christopher D;
Subject: RE: [soa-rm] Proposal:
Reorganization of SOA-RM Draft for Better
I believe that the
problem, with is largely due to the fact there is no normative reference for how
to interpret concept maps. In this case, a service is neither an action
nor an object. It is imply an abstract concept.
D
*******************************
Adobe
Systems, Inc. - http://www.adobe.com
Vice
Chair - UN/CEFACT http://www.uncefact.org/
Chair - OASIS SOA Reference Model
Technical Committee
Personal Blog - http://technoracle.blogspot.com/
*******************************
From: Metz
Rebekah [mailto:]
Sent: Wednesday, December 07, 2005 7:18
PM
To: Bashioum, Christopher D;
Subject: RE: [soa-rm] Proposal:
Reorganization of SOA-RM Draft for Better
From: Bashioum,
Christopher D [mailto:]
Sent: Wednesday, December 07, 2005 5:06
PM
To: Metz Rebekah;
Subject: RE: [soa-rm] Proposal:
Reorganization of SOA-RM Draft for Better
Rebekah,
what about the potential of an
act?
[->]
The potential of service is an offer.
I have a problem with the
following
<Snip>
The actual
invocation and performance of the capability is the service; i.e. the
action.
</Snip>
if I
understand what you are saying here, it would imply that a service is not a
service until it is actually performing an action. During the time that it
is "waiting" to perform an action it is not a service, nor is it after it has
completed the action it was created to do.
[->]
yes, you are right. That is exactly what I’m implying. The service
isn’t performing the action, the implementation of the action is. The
service is the performance.
In Duane's
diagram, the service exists independent of the interaction. However, the
interaction is what causes the real-world effect.
I'm not
sure I buy the other statement that a service is an act as opposed to an
object. Isn't it an object (in that it exists) who's purpose is to perform
an act?
[->]
So I’ll ask a question in return. Let’s assume the statement is
true. If a service exists as an object that is independent of the
capability who’s purpose it is to perform; what differentiates the service from
the capability?
For
that matter, is the capability what is actually providing the "action" and the
service is the means to access that action?
[->]
From this perspective, what differentiates the service from the service access
point?
[->]
My point is that the conceptualization of service as an object doesn’t provide
resolution to these questions. It is for this reason that I started
examining service as a verb rather than a noun. From that perspective, the
concepts and the relationships between them clarified.
Rebekah
From: Metz
Rebekah [mailto:]
Sent: Wednesday, December 07, 2005 4:37
PM
To:
Subject: RE: [soa-rm] Proposal:
Reorganization of SOA-RM Draft for Better
Gosh –
if this email came through in some weird format for everyone else, I am
terribly sorry about the wacky formatting of this email thread. Not sure
if everyone saw it as I did, but at least my outlook client puked
=)
Uh-oh. We seem
to be starting to head back to the service as an object as opposed to an
act. I still do not believe that a service is an ‘object.’
In fact, I believe that assumption has caused much of the
difficulty in figuring out what a service actually is.
What is
invoked is a capability, consistent with the execution context and so to
produce real world effects. The actual invocation and performance of the
capability is the service; i.e. the action. Hence I maintain that
visibility, interaction and effect are the interrelated concepts often (yet
confusingly) referred to with a shorthand nomenclature of
‘service.’
As far
as roles go, the very essence of the word service is the recognition that
<someone> does <something> for <someone else>. I would
agree that any other specification of this generalization (uh…isn’t that an
ontology) belongs in something other than the RM.
Rebekah
Rebekah
Metz
Associate
Booz Allen
Hamilton
Voice:
(703) 377-1471
Fax: (703)
902-3457
From:
Ken Laskey [mailto:]
Sent: Wednesday, December 07, 2005
4:19 PM
To: Metz Rebekah
Cc: Jones, Steve G; ;
; ; ;
; ;
; ;
Subject: Re: [soa-rm] Proposal: Reorganization of
SOA-RM Draft for Better
inline
On Dec
7, 2005, at 4:00 PM, Metz Rebekah wrote:
Comments inline…
From:
Ken Laskey [mailto:]
Sent:
Wednesday, December 07, 2005 3:43 PM
To:
Jones, Steve G
Cc:
; ; ;
; ;
; ;
;
Subject: Re:
[soa-rm] Proposal: Reorganization of SOA-RM Draft for Better
If I
invoke a service, I am a service consumer. It does not matter if I invoke
the service on my own initiative or am told to do it (through a targeted
instruction or as part of a more complex set of instructions), I am still
the service consumer.
[->] Agreed.
I
could glibly say that if I "provide" a service, I'm a service provider, but
I fear things are not that simple. Is the entity that created the service
its provider, or the one who maintains it, or the one who hosts it, or the
one who pays for it, or ...?
[->] I see this
being a question of ‘what are the roles’ versus ‘who plays the
roles’. At first pass, it seems right that we recognize the
roles @ the RM level and leave the details of determining the best way to
decide how to assign some entity into that role to the RA.
I think
it is easy to start naming roles but difficult to stop, and the roles will get
more use-specific.
Luckily, from the
RM standpoint, we don't care.
[->] or do we
just delegate =)
... to
someone who has no choice but to care ;-)
To be
used within the context of SOA, the service must be visible, must be able to
take part in an interaction
[->] Here it
sounds like the service is an active player in an interaction. Isn’t
it that the service consumer and provider interact (as specified…?
Isn't
the service an active player? I invoke it to get its real world effect, so it
certainly sounds like it does something.
(as
specified by the established execution context), and must produce a real
world effect (which I assume may in some circumstances be null). It has been
"provided" but we don't care how or by whom.
So, in
summary, there's a lot of muddy water but sometimes we can avoid playing in
it. :-)
[->] Or we can
draw a circle around it and leave that to the RA =)
... at
which point you initially choose RA cases that you can more cleanly defined.
You eventually get to the tougher ones, but we should learn to ride a bicycle
before we get a motorcycle (unless Duane has a different perspective)
Ken
[->] Rebekah
Ken
If I
make a service available for someone to invoke (and here I would say that
"make available"
On Dec
7, 2005, at 4:47 AM, Jones, Steve G wrote:
To
add some mud into the water…
Many
Bus architectures do “enrichment” of messages between consumer and
producer, including the invocation of other services to perform that
enrichment (e.g stock quote returns current price, enrichment provides the
last ten days closing price). They may also do calculations that
result in the non-connection or “empty” return from the service (e.g. if
you call for “last five minutes trades” after the market has closed… its
an empty set). So while I agree that the service consumer is key
it’s sometimes hard to identify the true consumer and the true producer of
a service within a virtualised bus.
Steve
From:
[mailto:]
Sent: 06 December
2005 19:09
To:
; ; ;
; ; ;
;
Cc:
Subject: RE:
[soa-rm] Proposal: Reorganization of SOA-RM Draft for Better
I
agree with Ken.
The
service consumer is the key concept that indicates the entity that invoked
the service in the first place.
A
brokering service or service actor is merely a middle-man.
Wes
-----Original
Message-----
From: Ken Laskey
[mailto:]
Sent: December 6,
2005 2:02 PM
To:
; ; ;
; ; ;
Cc:
Subject: RE:
[soa-rm] Proposal: Reorganization of SOA-RM Draft for Better
I
could argue that a broker consumes the service on someone else's
behalf. In reality, service actor seems too nondescriptive because
either the consumer or the provider can be thought of as an actor.
Ken
At
01:45 PM 12/6/2005, wrote:
I
hate to stir things up a bit, but can you change the service consumer term
to service actor?
Since in the case
of brokering the service actor is not consuming but brokering a request to
another service.
The
broker service can be a service actor upon the service but might not
really consume any part of the service since it is a pass through.
But
I guess this is a matter of opinion.
-
Dan
-----Original
Message-----
From: Ken Laskey
[ mailto:]
Sent: Tuesday,
December 06, 2005 10:39 AM
To:
Duane Nickull; Goran Zugic; Matt MacKenzie; MATHEWS, Tim; Sally St. Amand;
Cc:
Subject: RE:
[soa-rm] Proposal: Reorganization of SOA-RM Draft for Better
I
think we need to add some words to the RM to capture this
discussion. We cover part of this in the beginning of Section 3.2.1
but need to be more specific that:
- a
service consumer can be a human or a software agent;
- a
service consumer can invoke any number of services (including a single
service in isolation) and can chain the output of some services to act as
the input of others;
-
from the perspective of a given service, the occurrence of such chaining
would not be visible;
-
the service consumer can be implementing a business process;
-
the specific of a business process do not change the basic SOA concepts as
described in the RM; however, the specific architecture that one designs
and implements will reflect the business process and make use of specific
service instances that corresponds to the real world effects that the
business process hopes to realize.
Now
that said, and in full appreciation that we agreed earlier that mechanisms
which combine services (e.g. choreography, orchestration) are out of
scope, is it sufficient for words, such as those suggested above, to be
included somewhere within the current discussion or do we need to pull it
out into a subsection on its own? As an example of the former, we
tried to deal with loose-coupling and coarse-grained with words at the end
of Section 2.1.
Ken
At
12:23 PM 12/6/2005, Duane Nickull wrote:
Goran:
I
slightly disagree with your assertions, probably based on semantics.
For a service to "participate" in a process, it would have to be aware of
the process (which many will not be). A better way to depict this
may be to state "services may be aggregated and used by processes" and
"processes may be represented/exposed as services". There are really
no limits to the number of layers that can be present. Attached is a
UML CVD depicting such.
A
key rationale of why process is not part of SOA is that services cannot
see process. They are not aware of whether they are being called as
part of a process vs. as an individual service. If the "s" part of
SOA cannot see or touch that, it cannot be part of the RM.
The
chicken and egg discussion you bring forward is a requirement for those
building services to strongly consider the business process when designing
their service infrastructure. Accordingly, it is not really part of
the RM for SOA yet I agree that it is a very important consideration.
For
your messages to get to the list, you must join as a "applicant" rather
than an "observer" as per OASIS process.
Duane
*******************************
Adobe Systems, Inc. - http://www.adobe.com
Vice Chair - UN/CEFACT
http://www.uncefact.org/
Chair - OASIS SOA
Reference Model Technical Committee
Personal Blog -
http://technoracle.blogspot.com/
*******************************
From: Goran Zugic
[ mailto:]
Sent: Monday,
December 05, 2005 8:47 PM
To:
Duane Nickull; Matt MacKenzie; MATHEWS, Tim; Sally St. Amand;
Cc:
Subject: Re:
[soa-rm] Proposal: Reorganization of SOA-RM Draft for Better
Duane,
Thanks for the
response. Yes I would like to see the PPT. I hope you do not mind if I add
few more thoughts related to services and business processes:
Services
participate in a business process to add some value to it. They can be
governed and evaluated using business process metrics. One service can
participate in many business processes and provide value to each of them
according to the context within that process. As far as SOA is concerned
it is as important to know what the service does, how it can be
discovered, contacted, invoked, executed, etc. as it is to be able to use
it within the process context, measure it and assess its value from the
business process requirements point of view. SOA needs to avoid typical
new technology chicken and egg syndrome, e.g. companies not producing
services because there are no service friendly process definitions to use
them and not having SOA friendly process definitions because there are no
services to use. Services do not have to know if they will be involved in
the process upfront, they will be contacted on demand according to the
process script that is in effect, and they will be contacted, checked if
available, passed the arguments, collected the response and according to
their procedure left alone to wait for another call. The process execution
engine however needs to invoke the service according to both service
specific information and the process specific information.
Having just the
service specific information in a model covers only one part of the
picture and I think it is fine as long as that model is a pure service
model. However I find it difficult to understand that the SOA RM TC model
is a SOA reference model when it does not include other concepts of SOA.
Unfortunately it seems that we cannot get to the point where we could
agree on a minimal set of supported SOA concepts by a model to be the SOA
RM. We do not have to and I do not want to argue with you or anybody
else in SOA RM TC. I am just trying to see how our works can fit together
in a most efficient way. We obviously need more time to better understand
each others thoughts and ideas and I strongly believe that a constructive
respectable discussion is helpful for everybody.
By
the way, do you know what I am supposed to do to get my messages to the
SOA RM list. In spite of that I am the SOA RM TC observer I get a faliure
notice whenever I send a note to the SOA RM.
Goran
----- Original
Message -----
From: Duane
Nickull
To:
Matt MacKenzie ; ; MATHEWS, Tim ; Sally St.
Amand ;
Cc:
Sent: Monday,
December 05, 2005 5:02 PM
Subject: RE:
[soa-rm] Proposal: Reorganization of SOA-RM Draft for Better
Goran:
The
service layer enables the process layer over top of it, however during
runtime, services do not know if they are part of a process or being
called individually (it would generally be a bad idea to try to maintain
the overall state of a process within each service, although it could be
done). For maximum repurposing of services, it would be better to
have the service as a simple slave to the processes that may use it.
Accordingly, we
made a decision that BPM, Orchestration, choreography is not a core part
of the RM for SOA. We generally seem to agree that many SOA
implementations will include a layer of BPM over top. We are only
addressing the SOA model, not the model for the underlying or overarching
layers.
I
have a PPT that explains this in more detail if you are interested.
Duane
*******************************
Adobe Systems, Inc. - http://www.adobe.com
Vice Chair - UN/CEFACT
http://www.uncefact.org/
Chair - OASIS SOA
Reference Model Technical Committee
Personal Blog -
http://technoracle.blogspot.com/
*******************************
From: Matt
MacKenzie [ mailto:]
Sent: Monday,
December 05, 2005 12:51 PM
To:
; MATHEWS, Tim; Sally St. Amand;
Cc:
Subject: RE:
[soa-rm] Proposal: Reorganization of SOA-RM Draft for Better
Process
orientation is only one of multiple potential integration with service
oriented architecture. SOA-RM is laying the foundation for durable
architecture based on the core concept of service orientation. We
recognize that process oriented architecture is a natural fit with service
orientation...but so are things like event orientation.
-matt
From:
[ mailto:]
Sent: Monday,
December 05, 2005 3:36 PM
To:
MATHEWS, Tim; Matt MacKenzie; Sally St. Amand;
Cc:
Subject: Re:
[soa-rm] Proposal: Reorganization of SOA-RM Draft for Better
I
think that SOA RM has done good job documenting well-known service related
concepts and defining some new ones.
I do
not see other details besides service and service-related concept
definitions in the current SOA RM committee draft right now. I look
forward to seeing the completion of the model you are working on with the
bottom-up approach.
Business,
business processes and collaboration aspects of business are important to
address in the model what is not the case with the current content of the
SOA RM committee draft. By a business process I mean a generic business
process entity which has common components (activities, decisions, etc)
and relationships between them that can be used to model a business
process in any environment regardless of what business we support and
technology we use. I agree with Sally that a link between business
processes and services should be one of key requirements any SOA reference
model should try to meet.
I am
not sure what SOA with services brings to business when the link between
the business processes and services and overall business process semantics
in the SOA context are not considered to be important aspects in a
SOA-based reference model.
Goran
-----Original
Message-----
From: MATHEWS,
Tim [ mailto:]
Sent: Monday,
December 5, 2005 12:34 PM
To:
'Matt MacKenzie', 'Sally St. Amand',
Cc:
Subject: RE:
[soa-rm] Proposal: Reorganization of SOA-RM Draft for Better
"Componentization"
Matt
- I am not sure what point you are trying to make by this? I agree
with your premise of a bottom up effort, as this was one of the operating
assumptions that was made from the beginning.
But,
I am confident it is the business environment that is independent from the
reference model.
TM
From: Matt
MacKenzie [ mailto:]
Sent: Monday,
December 05, 2005 11:58 AM
To:
Sally St. Amand;
Cc:
Subject: RE:
[soa-rm] Proposal: Reorganization of SOA-RM Draft for Better
"Componentization"
Sally,
A
reference model actually needs to be a bottom up effort. We leave
the ever so popular ?top-down? approach to folks like ebSOA J
We?re creating a
vocabulary and general understanding of what I hope we can call a
discipline of computer science in the future. This means, we need a
durable reference model that is not dependent on the current business
environment.
-matt
From: Sally St.
Amand [ mailto:]
Sent: Monday,
December 05, 2005 10:19 AM
To:
Cc:
Subject: Re:
[soa-rm] Proposal: Reorganization of SOA-RM Draft for Better
"Componentization"
Frank
This
is in response to your request on last week?s conference call, if anyone
has comments speak now. I also think that the recent comments on
clarifying sections are a reflection of my issues with the specification.
I
agree with the majority of points made/described in ver 10. My issues are
with what is not in this draft. Based on Fig 1 the Refe! rence Model is
guided by Reference Architectures, Concrete Architectures, Profile &
Related Models. They in turn account for requirements, motivation &
goals. This is creating a Reference Model from the bottom up. I believe a
Reference Model should reflect a top down approach.
The
Reference Model needs to reflect the environment, the strategy and the
priorities of the business/mission/collaboration. This will impact
the construction of services. A service is a business task or activity
that is realized through technology. The draft does a good job of
describing how that realization happens. But it doesn?t provide a
sufficient link between processes and services. The draft makes the point
that the central focus of! SOA is the task of business function?getting
something done. A business process is made up of tasks and activities to
achieve a goal (getting something done). The concept of creating the
service from the tasks and activities in a process is important. For
example, where on the continuum of fine grained to coarse grained should a
particular service be; this will affect interaction, reusability. The
relationship between processes and services needs to be in the Reference
Model.
While I saw that
there is a note saying the glossary is still in flux, since one of the
objective of the Reference Model is a vocabulary, having less in the
glossary might be a better option. Is semantic integration a guiding
principle of SOA?
With
respect to conformance there needs to be business results. That is an SOA
should provide demonstrable mission accomplishments, e.g. ROI, match a
competitors distribution channel. SOA is not a technology. Conformance
should provide operational accomplishments, these should be measurable.
Sally
!
