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Act versus Object versus...both?
The phrasing Chris selected prompted something for me…let me see if I can put words to it. After the discussions yesterday, I spent some time last night reading linguistic research to try and better understand what about the relationship between noun and verb forms of ‘service’ are sticking points for me. As I suspected; it has to with the implications about the relationships between these lexical forms. What was most interesting was to realize the variety of aspects to be considered. However, I think that I found what makes me want to tread careful and clearly understand and distinguish between service as a noun and service as a verb. In addition, the phrasing you selected suggested that there are two active portions of the ‘service scenario’: 1) That ‘of bringing a desired capability to bear’ 2) That of the capability itself I’m looking right now at the first active portion only. I think we already recognize the distinction between the two in wd-10. But this served as a reminder to me. Essentially, when using the nominalized form of an active verb like ‘to serve’ in a sentence; an abstract noun performs most of the work. Nominalization can also permit the elision of the subject and object of a verb. Therefore, we can write about a process or action and yet not mention who is involved. This is part of the sticking point for me when it comes to a reference model in which we’re trying to unambiguously define key concepts – because we’re using terminology that permits us to unintentionally cloud the concepts when we are seeking clarity. Harrumph. To me this still wasn’t completely satisfying. So I dug a bit further and discovered that there are many ‘types’ of nominalizations, including ‘episodic nominalizations.’ An episodic nominalization takes an active process and conceives it as a noun. So far so good, for service as both noun and verb. However, here’s where I found some interesting information about the intuition of language that is captured by these different forms. Although quite similar, these two forms represent a different semantics which conceptually develop. In an episodic nominalization, the conception is no longer viewed as a process but rather as a single episode (i.e. only as the sum rather than the sum of its parts). Yes this starts to get into cognitive psychology and linguistics ( and I apologize to those who just want to know what does the word service mean within the context of SOA but bear with me). Where I got to is that yes, we may actually be talking about the same thing but from different angles. What I’m recognizing is that those angles come with specific inferences and assumptions that stem from language itself that we may not be explicitly aware of and which set up confusion. So what am I saying? That the text in the draft works well to recognize that the term service(noun) unifies several related concepts – and we do it justice to recognize those interrelated concepts. Using the terminology above, they’re conceptualized into a single episode. If we are clear about that, then I’ll accept that a service can be intended as either. (Now you all know how I spent my evening) Rebekah Rebekah Metz Associate Booz Allen Hamilton Voice: (703) 377-1471 Fax: (703) 902-3457 From: Bashioum, Christopher D [mailto:] Sent: Thursday, December 08, 2005 9:52 AM To: Chiusano Joseph; Subject: RE: [soa-rm] Proposal: Reorganization of SOA-RM Draft for Better 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 !
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