Andreas Hartmann
Tue, 26 Aug 2008 00:24:54 -0700
Joerg Heinicke schrieb: […]
XML NAMESPACES ------------------------------- Corona currently uses three different namespaces in XML documents: http://apache.org/cocoon/corona/sitemap http://apache.org/cocoon/corona/servlet http://apache.org/cocoon/corona/controller These namespaces are without a version number. Since I don't see how version numbers could help, I propose http://apache.org/cocoon/sitemap http://apache.org/cocoon/servlet http://apache.org/cocoon/controllerI know I'm rather late ...Don't these version numbers just help in the same way as versioned jars help? It's possible to signal additional functionality or incompatibilities. Just look at the Spring framework.
IMO version numbers in namespaces do more harm than good. From a user's point of view it needs much concentration to avoid mistakes if more than one namespace is available for a particular markup. If the namespace changes when functionality is added (e.g., a document format becomes more expressive), it's not backwards compatible anymore, i.e. components handling the namespace have to be updated.
If the changes are not backwards-compatible:In some cases additional markup can be used to express the version (like for instance the version attribute in XSLT). Where this is not possible, it might make sense to create a new meaningful namespace URI.
Just my $0.02, I'd be very interested in the opionions of others. -- Andreas -- Andreas Hartmann, CTO BeCompany GmbH http://www.becompany.ch Tel.: +41 (0) 43 818 57 01