Hi There is talk here of "aggregate services" and "composite services". Are they the same thing or different?
Thanks Ashley Michael Poulin wrote: > Absolutely agree, Harm. > > However, we are talking about integration capabilities of the service > itself. The nature of an aggregate service suggests integration in the > service implementation with engaged services. This is why an aggregate > service can participate in the choreography while atomic service cannot. > > Consumer does not distinguish between aggregate and atomic services. > This created additional challenge for the atomic service in the > Service Description document because such service > becomes responsible to the consumer for all business functionality and > RWE of engaged services while they are not under the control of > the aggregate service (and may belong to different ownership realms). > > Actually, the ownership and accountability of the service provider is > an interesting topic in the context of integration. But it is not > about Yefim's statement and may deserve another thread. > > - Michael > > ------------------------------------------------------------------------ > *From:* Harm Smit <[email protected]> > *To:* [email protected] > *Sent:* Tuesday, December 23, 2008 10:42:05 AM > *Subject:* RE: [service-orientated-architecture] Re: Yefim Natis is > sure that "SOA is integration" > > "In contrast, an aggregate service – does.” > > > > Why? > > IMO, a composite service made up from atomic services should itself be > perceived from the outside world as a self-contained service and it > should not need any services other than those used for its composition > to provide its RWE. As seen from the outside world, there is no > distinction between an atomic and a composite service and, since a > service hides its implementation, the outside world should be unaware > of how a composite service orchestrates its subordinate atomic > services (or other composite services, for that matter). > > > > Harm. > > > > ------------------------------------------------------------------------ > > *De :* service-orientated- architecture@ yahoogroups. com [mailto: > service-orientated- architecture@ yahoogroups. com ] *De la part de* > Michael Poulin > *Envoyé :* mardi 23 décembre 2008 10:50 > *À :* service-orientated- architecture@ yahoogroups. com > *Objet :* Re: [service-orientated -architecture] Re: Yefim Natis is > sure that "SOA is integration" > > > > Here is a misunderstanding, Rob. Certainly, to run, a service needs an > external call. However, self-contained atomic SOA business service > does not need any other business services to provide its RWE; it does > not know about outside world of services. In contrast, an aggregate > service – does. > > - Michael > > > > ------------------------------------------------------------------------ > > *From:* Rob Eamon <rea...@cableone. net> > *To:* service-orientated- architecture@ yahoogroups. com > *Sent:* Tuesday, December 23, 2008 4:01:52 AM > *Subject:* [service-orientated -architecture] Re: Yefim Natis is sure > that "SOA is integration" > > --- In service-orientated- architecture@ yahoogroups. com > <mailto:service-orientated-architecture%40yahoogroups.com>, Michael > Poulin <m3pou...@.. .> wrote: > > > > Integration with what? > > > > Assume, we have a self-contained atomic SOA business service. It > > does not need anything outside its boundaries to perform announced > > business functionality and provide for the RWE. > > Oh yes it does. A service all by itself does nothing. Without some > external stimulus, it does nothing at all. > > Something outside of the service must call it via one of the exposed > interfaces or the service will do nothing whatsoever. > > > Certainly, it has to run in an execution environment and it > > integrates with it. However, it does not integrate with an > > orchestration or a process that uses it because it perfectly > > functions alone. > > The orchestration or process integrates with the service by > connecting to and invoking one of the service's exposed interfaces. > > > Invocation of such service does not generate any new business value. > > Invocation of a service is required to generate any busines value. A > service uninvoked is a useless pile of bits. > > > As I responded to Rob, if a SOA service does not have an interface > > for particular type of communication channel, does it " have > > intrinsic seamless integration capabilities" ? > > No. But then how did the architect miss that channel? But for the > channels/interfaces that are not missing, the system has intrinsic > integration capabilities. > > > So, integration is just a link system between participants (may be > > one link for 2 participants) . Connecting those participants we do > > not create a SOA system, or we do? > > Connecting participants creates an integration. Creating an "SOA > system" (a term I loathe) requires creating service providers with > separately standing interfaces that are invoked within an execution > context by service consumers. Consumers integrate with providers via > the agreed upon interfaces. > > -Rob > > > > > ------------------------------------ Yahoo! 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