Re: What are web services ?
> > >Although no single, authoritative definition exists for basic terms like "service" and "Web Service", here are some fundamental characteristics that some folks believe that anything described as a "Web Service" should possess: > >(1) Can interact with it through the WWW; > > Yes, this seems to be one of the goals. I saw in many article praising web services that they can pass thru standard proxies+firewalls because they are based on HTTP (like SOAP is) >(2) Platform- and programming language-agnostic; >(3) Interface & invocation requirements are well-described; > > I can some up with some well-described (in my opinion) protocol but that doesn't mean that it is going to be a web service. Microsoft can some up tomorrow with some new protocol called "M-SUPER-C" that will meet the above constrains but that does not mean that this is a web service. So point 3 is only valid toghether with point 9. >(4) XML-encoded interaction mechanism; > > This is true according to W3C, but is this valid in the general sense ? Who says that a web service must be text-based and not binary ? >(5) Payload most often is XML; > > "Most often" cannot be part of a definition. >(6) Loose coupling between invoker and Web Service; > > You mean it must not have a state (like HTTP) ? >(7) Performs a specific, well-defined function; > > !!!? I am really tired of such high level super-generic definitions. What entity in the computing world isn't supposed to be specific and well-defined ? >(8) May invoke other Web Services; > > Remote invocation is not big deal. How about a self-describing feature (WSDL) ? Can a "service" be called a "web service" if it doesn't have this feature ? How about automatic discovery (UDDI) ? Is such a feature an integral part of a web service or is it just optional ? Of course WSDL and UDDI are just implementations. You can replace those with ASDF and YRRT or whatever. >(9) Standards-based; >(10) Has the ability to perform its functionality synchronously or asynchronously, as needed; (i.e. does not use synchronous interaction when asynchronous is best, and vice-versa); > > Can you please explain what you mean by this ? -- Regards, Razvan SCJP preparation material: www.mihaiu.name/2004/sun_java_scjp_310_035/index.html www.mihaiu.name/2004/sun_java_scjp_310_035_test1/index.html www.mihaiu.name/2004/sun_java_scjp_310_035_test2/index.html www.mihaiu.name/2004/sun_java_scjp_310_035_test3/index.html www.mihaiu.name/2004/sun_java_scjp_310_035_test4/index.html
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