[jdom-interest] Inconsistancy in Namespace.hashCode().
jeff at socialchange.net.au
Sat Mar 3 17:09:08 PST 2001
On Sat, Mar 03, 2001 at 10:34:08AM -0500, Elliotte Rusty Harold wrote:
> At 2:45 PM -0800 2/28/01, Jason Hunter wrote:
> >Good eye. I've changed the documentation on my local copy to be:
> > * This returns a probably unique hash code for the
> > * If two namespaces have the same URI but different prefixes, they
> > * have a different hash code.
> >This correctly defines the behavior, and I think the existing behavior
> >is correct. Anyone (Elliotte esp) have concerns?
> Yes, I disagree. I'm not sure when the mistake got in, but the
> comment is correct (i.e. it describes the right behavior) and the
> current code is wrong. Two namespaces are equal if their URIs are
> equal. The prefix should not be considered when testing for equality.
> I suppose you can argue that two Namespace objects are not equal if
> they describe different prefixes. Maybe that makes sense, but it
> makes me deeply uncomfortable.
> I guess the question comes down to what the use case for comparing
> namespaces is. I would expect that the equals method would let us
> take two set elements with possibly different prefixes, possibly one
> in a default namespace, and determine whether or not they have the
> same type; e.g. are both MathML set elements or is one a MathML set
> element and one an SVG set element? This only works if we compare
> based on URI and not prefix.
Hmm.. that's exactly the scenario I find myself in, having parsed a document
<e xmlns="foo" xmlns:gml="foo"/>
I didn't see anything disallowing multiple prefixes in the namespace WD.
Now I'd like the following to be true:
( Namespace.getNamespace("foo").equals ( Namespace.getNamespace("gml", "foo")) )
Does that match most people's expectations?
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