[jdom-interest] Reading the xml:base attribute

[Bradley S. Huffman]

"Michael Kay" writes:

> JDOM doesn't offer a method signature
> 
>    getAttribute(String lname, String uri)
>
> instead one has to do
> 
>    getAttribute(String lname, Namespace.getNamespace(uri))
> 
> But this fails if the uri happens to be the XML URI, e.g. if you're trying
> to read xml:base.

As it should. From Namespace.getNamespace(String) javadoc

    This will retrieve (if in existence) or create (if not) a Namespace for
    the supplied URI, and make it usable as a default namespace, as no prefix
    is supplied.

And you cann't map  http://www.w3.org/XML/1998/namespace to the default
namespace.

> In this case you need to do
> 
>    getAttribute(String name, Namespace.XML_NAMESPACE)

Or getAttribute(name, Namespace.getNamespace("xml", "http://www.w3.org/XML/1998/namespace")).

> Why should an application retrieving an attribute in the XML namespace need
> to handle this differently from an attribute in any other namespace?
> 
> Suggestion: Namespace.getNamespace(uri) when the uri is the XML namespace
> should not fail, but should return Namespace.XML_NAMESPACE. 
> 
> Incidentally, I assume the prefix in the Namespace object makes no
> difference to the results of getAttribute(), but the documentation doesn't
> make this clear.
> 
> Also, I've always assumed that Namespace.getNamespace("") returns the
> non-namespace, and indeed (looking at the source code) it does, but I now
> see that there's nothing in the documentation to justify this assumption.

JDOM currently doesn't have such a method, but are you looking for a
getInScopeNamespace(String uri)?

Brad