The schema would be useful for validation markup files and for xml editors to provide content assist.
The schema is added as wicket-core.jar#META-INF/wicket-1.5.xsd with r1125052.
Updating patch. Fixing regular expression for wicket:message attribute.
I was asked to provide some info on how to test the schema with Eclipse, so here it goes. With Eclipse 3.6.2 (Helios) this works:
1. Import the xsd in Window -> Preferences -> XML -> XML Catalog -> Add: browse the schema, make sure key type is "Namespace name" and key is "http://wicket.apache.org" (they should be automatically read from the xsd by Eclipse).
2. Open the example xml-s I am attaching with this comment. Play around with them. One should pass validation (pass.xml) and the other should report couple of errors (error.xml - no kidding).
Note however that Eclipse custom xsd based support is a bit weak. There are probably better xml editors that could take better advantage of the schema. For example Eclipse will ignore the schema if any of the followings is true:
Updating patch. Making validation for child elements from wicket namespace strict while keeping it forgiving for foreign elements. This way not defined wicket child elements are not allowed any more.
Updating patch. Removing wicket:component element following WICKET-3687.
Updating patch with limited wicket:id uniqueness support.
The xml validation will now fail if the wicket:id attribute value is not unique for the immediate child elements of (wicket border, component, container, enclosure, extend, fragment, head, link, message, panel elements.
Updating patch. wicket:component has an optional "name" attribute. Thanks Martin for finding these bugs in the xsd!
Updating patch again. Sorry for the spam.
Now the schema allows and requires to add wicket:id attribute to wicket:container and wicket:fragment elements.
Attaching updated patch. This contains a definition for wicket:container (which was missing from previous patch) and a few typo fixes.
Attaching a patch that adds a wicket-1.5.xsd to wicket-core. It could also be hosted on the website (next to the dtd-s) too.
It contains the wicket attributes and tags with some custom types and a few restrictions to help users provide valid values.
Documentation is mostly copied from the wiki.