I see no reason at all why service orientation would have to be based on components. For example, components not only have a contract with their caller, but also with a component environment into which they are deployed. Services don't (although service implementations may).
If anything, I think SOA inherits some, but not all aspects from a wide variety of technologies such as distributed objects, components, message-oriented middleware, EAI, EDI, and the Web. I also don't think there is a single "unique" feature service- orientation provides (nor do I think there has to be one). Stefan -- Stefan Tilkov, http://www.innoq.com/blog/st/ On Aug 22, 2006, at 1:02 AM, Jerry Zhu wrote: > Good question. But it can be well answered in line of > evolutionary standpoint. That is, we must be clear > the features of the technologies before service > technology. OO Objects are a central idea in COM or > COM objects are built on OO objects hence COM inherits > all features of Object technology(encapsulation, > polymorphism, and inheritance). Therefore COM is > objected oriented. If it's asking "are COM objects > exactly like objects in languages like C++?" The > answer is obviously No. The problems COM solves are > quite different from those solved by object > technologies. > > To know unique features Service technology provides, > we must first know what features Component technology > provides and how are the problems Component technology > solves different from those of Object technology. > Given the features Component technology provides, what > are the new problems service technology solves that > Component technology can not solve,and what new > features of Service technology can solve the new > problems. > > Jerry > > --- Hitoshi Ozawa <[EMAIL PROTECTED]> wrote: > > > Jerry, > > Interesting point that you've brought up. We say > > it's > > object oriented when it supports polymorphism, > > inheritance, > > encapsulation, and data abstraction. Is there any > > comparable > > properties necessary for SO? > > > > H.Ozawa > > > > Jerry Zhu wrote: > > > > > I think there is a difference between SW evolution > > and > > > > > > the evolution of a particular SW technology. My > > view > > > is that newer SW technology is built upon, does > > not > > > replace, older ones. Object technology is built > > upon > > > function technology (procedural languages are the > > > platforms). Component technology on object > > technology > > > and Service technoloyg on component technology. > > > > > > The newer technology uses the previous ones as > > > building blocks for its implementation. OO objects > > > will use functions to implement their methods and > > CO > > > objects will use OO classes to define their > > interfaces > > > and implement component classes. Service objects > > will > > > include Component objects for their > > implementation. > > > In SW evolution, the new technologies are > > inclusive > > > hence, inherit features of older technologies. I > > saw > > > a lot of talks about SOA features here. Most of > > them > > > belong to component technology such as separation > > of > > > interfact from implementation while little is > > talked > > > about the powerful features for SOA only. In what > > way > > > or how possible for SOA to do more with less. > > > > > > SW technology is about economics that is to do > > more > > > with less which is possible by doing different > > things. > > > Polymorphism is a different thing to do when > > > comparing with procedural languages. Style is > > about > > > alternatives, doing the same thing in alternative > > way, > > > and often related to cosmetics and luxiury such > > life > > > style. > > > > > > One can write polymorphism using C and saying OO > > is a > > > style by not using Object technology. If so, we do > > > less with more. We may not use SOAP, XML, BPEL, > > etc > > > and say we are implementing SOA, It depends on how > > SOA > > > is defined or you do less with more. > > > > > > One can implement SOA based on procedural > > languages. > > > In this case the two SW evolutionary technologies, > > > object technology and component technology, are > > > ignore, then either lots of features of Object > > > technology and Component technology are missed or > > you > > > do less with more. > > > > > > Jerry > > > > > > > > > > > > > > > > > > > > > > > > __________________________________________________ > Do You Yahoo!? > Tired of spam? Yahoo! Mail has the best spam protection around > http://mail.yahoo.com > > > Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/service-orientated-architecture/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
