First, technology simply means, as I recall from a
comprehensive definition, new ways to do (same) things
with significant improvement or do new things
impossible in old ways. All computer languages are
technology platforms. Different computer languages are
different embodiments of same or different
technologies. You can go to CA from NY by bike or by
airplane. Are you saying bike and airplane are the
same technology?
Second, sw architecture by definition is technology
dependent and platform independent as we discussed
before. OO architecture will reflect elements of
object technology such as inherentance, encapulation,
polymorphism etc. SOA should contain elements of
service technology whatever the terms we use.
Architecture defines (not designs) the major elements
and their relations in a SW. Architecture is not
technology but only depends on one or more
technologies. If SOA is something distinct from OO
architecture then SOA should containt new technology
elements different from that of OO technology.
Third, aggregation and containment are two ways of SW
reuse in component (not object) technology because
component technology does not support implementation
inherentance. See, we have two different technologies
with different kinds of elements. Service is built on
components not on objects. That is why we see much
commonality between components and services. We have
characterize services in terms of components but not
much in terms of new technology elements. That is my
original question what is the new elements of service
technology that is not in object/component technology?
Regards
Jerry
--- Dan Creswell <[EMAIL PROTECTED]> wrote:
> Jerry Zhu wrote:
> > OO was considered as a new technology enabled by
> OO
> > languages. It won't be OO architecture
> implemented
> > with only procedural languages.
> >
>
> Surely OO is a design discipline not a technology?
> As a matter of fact,
> you can do OO in procedural languages, you just need
> an appropriate set
> of abstractions to do it.
>
> Early C++ implementations were done by
> pre-processing and converting
> back into C for the normal compiler to the turn into
> native code.
>
> I don't associated OO architecture with any
> particular technology - I
> conceive my OO architecture separately and then give
> it physical
> representation by converting it into a set of
> co-operating components
> written in whatever way is appropriate.
>
> > What is the (new) technology that enables SOA? Or
> What
> > is the technology that must be in an architecture
> to
> > be called SOA? I think it is XML and Component
> > technology. In the same way one can not develop
> OO
> > software with producal languages, one can not
> develop
> > SOA software without XML and Components.
> >
>
> And I think this is fundamentally why we have a
> problem. Architecture
> and technology are two different and separate
> things. One uses
> technology to implement an architecture but there is
> no specific
> requirement to use a particular technology for a
> specific architectural
> discpline - unless of course you introduce
> non-engineering concerns such
> as finance/licensing.
>
> I would of course concede that some technologies
> might make the
> rendering of architecture from logical to physical
> easier.
>
> > <Anne/> A service, therefore, is a representation
> of
> > this functionality that can be shared by multiple
> > applications. A service exposes it functionality
> > through a well-defined interface. Service
> consumers
> > (i.e., applications) use the interface to gain
> access
> > to the functionality. </Anne>
> >
> > What is described here is also applicable to
> Microsoft
> > COM objects (formally known as OLE controls or
> > ActiveX) (Java beans as equivelent?) back in 1996.
> > Should we say SOA has been already used in 1996?
> >
>
> Maybe we should be saying exactly that and in fact
> some are hence the
> comments about being able to do it with CORBA etc.
> This is because the
> basic architectural premise of SOA can be rendered
> into reality using a
> myriad of technologies both old and new.
>
> > I renew my question. What must be included in an
> > architecture to be called SOA? One may say
> nothing.
> > It is a style of design. Therefore one can write a
> SOA
> > software using Fortune only? Is it possible?
> >
> > My hunch is that the technologies required are
> > Component (distinct from Object) technology + XML.
>
> > One can write procedural SW with C++ but it is
> still
> > procedural, not OO, SW. To be OO SW, inheritence
> must
> > be used. To be SO SW, it must include service
> > description and service choregraphy. Without
> these, I
> > won't call the SW with a SOA eventhough it passes
> XML
> > messages. Without XML, I won't call it SOA
> either.
> >
>
> If I'm building a service-based thing, I need
> something that can model
> services. Probably I need something that can define
> the
> interface/contract for that service and how to
> locate the services I
> desire so I can use them. (The remaining issue is
> whether those
> services are distributed (that is networked) or not
> - if they're all
> in-process I'd qualify them as components, if they
> aren't, they're
> something else and I tend to call those services.)
>
> So what technology might I use? Maybe CORBA, RMI or
> app servers or WS
> or messaging or Jini or whatever.
>
> IMHO - OO is not defined by the fact you use
> inheritance. In fact, good
> OO makes use of a number of other concepts such as
> aggregation and
> composition. Inheritance, really, should only be
> about sub-typing but
> many use it to achieve re-use which is the wrong way
> to look at it.
> Composition and aggregation are about re-use and
> that's why those
> concepts are so visible in SOA.
>
> My two cents,
>
> Dan.
>
>
>
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
SPONSORED LINKS
| Computer software | Computer aided design software | Computer job |
| Soa | Service-oriented architecture |
YAHOO! GROUPS LINKS
- Visit your group "service-orientated-architecture" on the web.
- To unsubscribe from this group, send an email to:
[EMAIL PROTECTED]
- Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
