- From: Savas Parastatidis <Savas.Parastatidis@newcastle.ac.uk>
- Date: Sat, 19 Jul 2003 19:30:17 +0100
- To: <ksankar@cisco.com>, "Steve Graham" <sggraham@us.ibm.com>
- Cc: <public-ws-desc-state@w3.org>, <public-ws-desc-state-request@w3.org>
Krishna, The technology or programming model that is used to implement a web service is not of concern here. The discussion was about the web services architectural model. -- Savas Parastatidis http://savas.parastatidis.name > -----Original Message----- > From: Krishna Sankar [mailto:ksankar@cisco.com] > Sent: 18 July 2003 18:17 > To: 'Steve Graham'; 'Savas Parastatidis' > Cc: public-ws-desc-state@w3.org; public-ws-desc-state-request@w3.org > Subject: RE: attributes & WSDL (was: Re: attributes in CORBA IDL) > > Methinks ;-) : > > Objects and services are, in some sense, orthogonal. > > Let us not confuse interfaces with implementations. Interfaces > cross boundaries while implementations are always local. SOA, in a way, > is a mechanism to string the objects. > > The WS stuff, in some sense, are interfaces to define, describe, > distribute, discover and execute services. The services themselves would > be implemented in OO systems, COBOL or any other way the service > provider chooses. > > Double-clicking one more level, we have the object system and > the interfaces. We also have the wire format - which is what many of the > WS specifications are trying to standardize. Remember the wire format > not only includes the exchange of information and context (SOAP, SAML) > but also the capability to express one's infrastructure (using > WS-Policy, WS-federation et al). We also have the option to build higher > level abstractions by chaining services, using choreography, > transactions and other similar mechanisms. > > objects -> fronted by -> services -> chained by -> > choreography/transactions > > services -> use wire format (XML/SOAP/SAML) -> to exchange > information and express capabilities, policies > > services -> expressed by -> interfaces (WSDL) > > -k. > > > > -----Original Message----- > > From: public-ws-desc-state-request@w3.org > > [mailto:public-ws-desc-state-request@w3.org] On Behalf Of Steve Graham > > Sent: Thursday, July 17, 2003 9:25 AM > > To: Savas Parastatidis > > Cc: public-ws-desc-state@w3.org; public-ws-desc-state-request@w3.org > > Subject: RE: attributes & WSDL (was: Re: attributes in CORBA IDL) > > > > > > > > > > > > > > > > I do not concur that Objects imply tight coupling. They are > > orthogonal > > concepts. I have built systems using Object TEchnology that are very > > loosely coupled. > > > > CORBA and DCOM did not fail. They had certain successes, but > > they are not > > mainstream. COBOL, for example, is not currently top of > > mind, but I would > > not say that COBOL failed. > > > > sgg > > > > ++++++++ > > Steve Graham > > sggraham@us.ibm.com > > (919)254-0615 (T/L 444) > > STSM, On Demand Architecture > > ++++++++ > > > > > > > > > > > > > > "Savas Parastatidis" > > > > > > <Savas.Parastatidis@newca To: > > Steve Graham/Raleigh/IBM@IBMUS > > > > stle.ac.uk> cc: > > <public-ws-desc-state@w3.org> > > > > Sent by: > > Subject: RE: attributes & WSDL (was: Re: attributes in CORBA > > IDL) > > public-ws-desc-state-requ > > > > > > est@w3.org > > > > > > > > > > > > > > > > > > 07/17/2003 12:19 PM > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >I don't think object-based architectures are appropriate for a > > loosely > > > coupled, > > > >inter-organisation environment. > > > > > > Why? > > > > > > Objects imply a tightly coupled system. It's ok to build distributed > > applications using objects when you own the infrastructure, when you > > remain within the boundaries of your organisation. You have tighter > > control of what is going on. > > > > Once you start talking about inter-organisation, loosely coupled > > infrastructures, you have to live in an environment where you > > don't have > > control. My organisation will not allow you to create objects > > representing the resources I maintain. I am providing a service, an > > interface to what I want you to see. I am telling you the > > messages that > > you can exchange with me but not the resources that are > > hidden behind my > > service interface. I am not going to give you control of what can be > > created and/or destroyed behind my interface. > > > > A service is coarse grained. It's the entry point to my organisation. > > That's the way I chose for my communications with others. Through > > message exchanges of well-defined documents and not through > > method calls > > on a stateful entity, an object, that I allowed you to create on my > > resources. If I wanted that, I would have chosen CORBA or DCOM. > > > > CORBA failed! DCOM is dead! Let's not try to do the same mistakes. > > > > .savas. > > > > > > > > > > > >
Received on Saturday, 19 July 2003 14:30:47 UTC