[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] RE: basic qs - how is xml more flexible for exchanging data?
> My point had little to do with 'C'. I used it as a > point to be as basic as possible. To be more rigorous > I should have said Corba instead of 'C' and 'idl > struct' instead of 'C struct'. You should indeed, that changes the argument completely! Corba is a protocol with an associated language IDL. C is a language with no associated protocol. Corba/IDL is a viable way of exchanging data between distributed applications, C structs are not. So why has XML been more successful for this purpose than Corba? Partly commercial factors - the Corba environments I knew about were very pricey. This also accounts for the failure of ASN.1 to hit the big time. Partly for the reasons you outline below: XML has more flexibility for the different parties involved to make changes without all having to synchronize their upgrades. Partly because XML works over a wider variety of transports, synchronous and asynchronous; partly because different suppliers' XML implementations do actually interoperate whereas different suppliers' CORBA implementations often don't; partly because of Unicode; partly because when you get problems with a message you can look at it in a cheap text editor and understand what's wrong; ... Are any more reasons needed? Michael Kay http://www.saxonica.com/ > My point: For example in Corba, when an idl struct or > interface changes, then it is a major headache - every > client of the server has to be updated. At the very > least they must recompile their stubs and redeploy > their applications with the new idl interface in the > case if a new method is added with no other changes to > the interface; if the struct changed - say a new field > was added (not a modification or deletion which would > understandably affect everyone), then the server must > continue supporting the old struct as well as the new > one. For clients that want to stay with the old struct > (avoiding client code changes which they might not > need) the old servants must coexist with the new > servants in the server. I have seen this in practice > when the wireless telecom I worked at previously - > their Corba server had several independent wireless > resellers use it to exchange data. There was a good > deal of duplication in code and work and resources. > This is what I understand by tight coupling - which > reduces maintainability. > I thought that XML promoted loose coupling and > flexibility. I wondered if it was really so. > Additionally you now have the 'feature' of parsing of > tags and also type-conversion to get at the data. > thanks, > Anil Philip > ---- > > > for good news go to > http://members.tripod.com/~goodnewsforyou/goodnews.html > > > > __________________________________ > Yahoo! Mail - PC Magazine Editors' Choice 2005 > http://mail.yahoo.com >
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