--- Christian Riege <[EMAIL PROTECTED]> wrote: > hi, > > On Wed, 2002-11-13 at 22:36, Dain Sundstrom wrote: > > > (Don't know much about XML Schemas....maybe they > address these issues?) > > > > This is what XML name spaces are for. If in ISV > wants to add more > > config options to jboss, if jboss wants to add new > options to the spec > > ejb-jar.xml file, we just put it in a different > name space. Of course > > this only works with a schema because dtd don't > understand name spaces. > > hu? it has always been my understanding ( i might be > completely > wrong/off track of course :), that a namespace is > tied to a specific DTD > - so that you can have an XML document which > contains more than 1 DTD > that are referenced by the namespace of the > elements. > > from my current understanding, XML Schema is only a > more specific way to > describe element/attribute content than a DTD (e.g. > you can say "this > element is a string of 3 characters" in a schema > whereas a DTD only > specifies "this element has some content"). >
No, in addition to the concept of datatypes and native support for namespaces (and of course the very nice attribute that schemas are themselves XML, where DTDs are not), XML has much nicer extension mechanisms. Whereas DTD extension was done through the kludgy mechanism of entities, XML Schemas use allow you to define complex types using methods analogous to object composition and sub-typing. So, for example, you could have a <jboss-service-module> type defined which contained some bare minimum amount of config info for any jboss service, and ISVs could define their own schema which extended that datatype and added config info specific to their own service. Namespaces provide a mechanism for "protecting" your type definitions, and it's possible to use the <redefine> directive to add or change info for element types defined in the same namespace (for the "jboss group adds capabilities" case mentioned above). And someone mentioned an "include" mechanism: XML schemas have the <include> directive. So for a given set of modules you could have the configuration in one big file, or split out however you like. XML Schemas are very powerful, and I think they're a big win for *specifiying* config info (whether or not the in-memory representation is DOM or something else). Dave __________________________________________________ Do you Yahoo!? Yahoo! Web Hosting - Let the expert host your site http://webhosting.yahoo.com ------------------------------------------------------- This sf.net email is sponsored by: To learn the basics of securing your web site with SSL, click here to get a FREE TRIAL of a Thawte Server Certificate: http://www.gothawte.com/rd524.html _______________________________________________ Jboss-development mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/jboss-development
