[jdom-interest] Attribute name verification special casing for xml:base

[Jason Hunter]

I agree with what Brad said.  (Except on the "errata" issue I don't have
a strong opinion.  My gut instinct is just that it's wasteful to do a
string comparison against that namespace for all namespaces just to
ensure someone doesn't do something somewhat stupid, but whatever.)

I agree with your conclusion, Rusty, that special casing makes things
more complicated.

-jh-

"Bradley S. Huffman" wrote:
> 
> Elliotte Rusty Harold writes:
> 
> > I think it's best for JDOM to accept this paragraph at
> > least, and not allow other prefixes to be bound to
> > http://www.w3.org/XML/1998/namespace
> 
> +1
> 
> > Looking at the Namespace class with this in mind I see several bugs:
> >
> > 1. We allow other prefixes to be mapped to the
> > http://www.w3.org/XML/1998/namespace namespace. Arguably, this is OK
> > according to Namespaces 1.0, if not Namespaces 1.0 + errata. We may
> > not want to fix it.
> >
> 
> +1 Namespaces 1.0 + errata.
> 
> > 2. Someone can call Namespace.getNamespace("xml",
> > "http://www.someweirdURI.com") and get the
> > http://www.w3.org/XML/1998/namespace namespace back. This should
> > probably throw an IllegalNameException instead.
> 
> +1
> 
> > Now back to the Attribute class. The Attribute class is definitely
> > broken with respect to xml:base, xml:lang, and xml:space because of
> > the special casing. You can create such an attribute, but
> > getNamespacePrefix() and getNamespaceURI() return the empty string
> > and getNamespace() returns Namespace.NO_NAMESPACE. If we're going to
> > special case xml:space/xml:lang/xml:base, then we need to add extra
> > code to Attribute to handle the special cases, which can certainly be
> > done. It just makes the Attribute and Verifier classes somewhat more
> > complex.
> >
> > Son our options here are:
> >
> > 1. Remove the special casing completely from Verifier, and let
> > clients pass in the prefix, local name, and URI when they want to
> > create an xml:base, xml:space, or xml:lang attribute.
> >
> > or
> >
> > 2. Add xml:base to Verifier and add special casing for names that
> > start xml: to Attribute.
> >
> > I think the first solution is cleaner and more consistent with the
> > JDOM model, but I can write a patch for either one.
> 
> +1 for first solution.
> 
> > I also note that XMLOutputter has some code that doesn't work with
> > the current special casing because whoever wrote it was assuming that
> > the namespaces were in place:
> >
> >
> >      protected void printElement(Element element, Writer out,
> >                                  int level, NamespaceStack namespaces)
> >                         throws IOException {
> >
> >          List attributes = element.getAttributes();
> >          List content = element.getContent();
> >
> >          // Check for xml:space and adjust format settings
> >          String space = null;
> >          if (attributes != null) {
> >              space = element.getAttributeValue( "space",
> >                                                 Namespace.XML_NAMESPACE);
> >          }
> >
> > I don't know or remember who wrote this particular line of code. It
> > might even have been me. But clearly at least some programmers are
> > thinking of xml:space etc. as existing in a namespace. If we stay
> > with special casing, we'll need to fix this too.
> 
> Hmmm, this is a bug. If the doc is built with SAXHandler the above code
> works (if qname != local name, SAXHandler parses the qname), if built
> by hand it may or may not work depending on which constructor is used.
> 
> Brad