Thanks
- that was helpful.
That
being the case, the RM concept of a service maps to a concrete "thing" called a
service, that performs the action of bringing a desired capability to bear when
invoked in the context of an SOA - or at least an RM conformant SOA.
How's
that for a beltway insider?
From: Chiusano Joseph
[mailto:]
Sent: Thursday, December 08, 2005
9:41 AM
To:
Subject: RE:
[soa-rm] Proposal: Reorganization of SOA-RM Draft for Better
Please see comments below, marked with [JMC].
Joe
Joseph Chiusano
Associate
Booz Allen Hamilton
700 13th St. NW
Suite 1100
Washington, DC 20005
O: 202-508-6514
C: 202-251-0731
Visit us online@ http://www.boozallen.com
From: Bashioum, Christopher D
[mailto:]
Sent: Thursday, December 08, 2005
9:31 AM
To: Chiusano Joseph;
Subject: RE: [soa-rm] Proposal:
Reorganization of SOA-RM Draft for Better
Does that mean that all the elements in the concept map are only
concepts - none of them translate into objects or actions (or any other
concrete thing)?
[JMC] They translate into concrete things when an implementation is
created that conforms to the reference model (or an existing implementation
is mapped to it).
I
thought one of the purposes of a RM was to identify and give a language to
the basic elements of the thing being modeled. I.e., and SOA will have
all the elements that are identified in the RM.
[JMC] A SOA
*implementation* may have concrete elements that map to the abstract
elements (concepts) that are identified in the
RM.
I
think Ken's description is still the best one, that "a service is a
means to bring a capability to bear in an SOA context". In this
case, it is still a noun (or a thing) (or at least I think so, my wife is
the English major - not me)
[JMC] It is a
noun, as well as an action (alluding to my prior recent post on this). So in
comparison, a political compaign (sorry, I live in Washington DC;) can be
thought of as a means to potentially bring a candidate into elected
political office (using very loose wording here), while "to campaign" is the
action that is associated with that noun. If one had a reference model for
campaigns, it would contain concepts such as "candidate", "policitical
party", "regions" (perhaps the region(s) of the country that their campaign
would cover - a gubernatorial campaign would cover one state, a presidential
campaign all states), etc. In order to campaign (the action), one would
leverage the campaign reference model as a means to guide them in their
action of campaigning.
Joe
From: Chiusano Joseph
[mailto:]
Sent: Thursday, December 08,
2005 6:58 AM
To:
Subject:
RE: [soa-rm] Proposal: Reorganization of SOA-RM Draft for Better
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
!
