Hi Jeff
Sorry to spring that one on you - I meant to send an email describing the
experimental change to see what people thought.
I tried to document it in the patches section on the website
http://dom4j.org/todo.html
The quick answer is I'm going to change the code back again.
Now the longer answer over why I made the change...
My general thinking was, in documents without namespaces (or only using a
default namespace)
<foo xmlns="whatever">
<bar/>
</foo>
then the change to use qualified name rather than local name wouldn't make
any difference. Searching for name "foo" and "bar" would find the required
elements.
If however we were reading a document which uses namespace prefixes such as
an XSL stylesheet and we wanted to find a <xsl:template> element, comparing
only on the local name is kinda risky as we could find a <template> element
by mistake. (Or a <x:template> or whatever).
So I thought it might be cleaner, if you know what prefixes are being used
in a document that it might be more useful to search by qualified name. So
searching for "xsd:template" would match <xsl:template> but not <template>.
This is fine if you know what the prefixes were that were used. You could
argue that the prefixes are irrelevant and that you should, just like XPath
does, ignore what the prefixes are and just compare local name and namespace
URI. (i.e. only compare the URI that the prefix maps to)
So if you want to ignore prefixes, just compare local name and namespace URI
you can use the QName approach. I tend to do this by defining literals:-
e.g. if we had a document like this:-
<x:foo xmlns:x="http://www.x.com/x/1.0";>
<x:foo id='123'/>
<x:bar name="James"/>
</x:foo>
or this
<foo xmlns="http://www.x.com/x/1.0";>
<foo id='123'/>
<bar name="James"/>
</foo>
the following code would work, and wouldn't find any elements 'by mistake'
which are in the wrong namespace.
import org.dom4j.Element;
import org.dom4j.Namespace;
import org.dom4j.QName;
public class Foo {
public static final Namespace NAMESPACE = Namespace.get( "x",
"http://www.x.com/x/1.0"; );
public static final QName FOO = QName.get( "foo", NAMESPACE );
public static final QName BAR = QName.get( "bar", NAMESPACE );
public void doSomething( Element root ) {
Element foo = root.element( FOO );
Element bar = root.element( BAR );
...
}
}
You can use the QName literals as if they were Strings "foo" and "bar"
except they properly compare element (and attribute) names, via only local
name and namespace URI.
So to cut a long story short, I've now convinced myself again that we should
have 2 ways of comparing element names - using local name only (as the code
was until I patched it yesterday) and by comparing QNames (local name and
namespace URI).
What I will do though is add a helper method to Element to make it easier to
get a QName for a qualified name. e.g.
// find all elements with a local name of "foo"
// in any namespace
List list = element.elements( "foo" );
// find all elements with a local name "foo" and the default namespace
URI
List list = element.elements( element.getQName( "foo" ) );
// find all elements which match the local name "foo" and the namespace
URI mapped to the "x" prefix
List list = element.elements( element.getQName( "x:foo" ) );
I'll patch the code to implement the above and mail when its available.
James
----- Original Message -----
From: "Jeff Turpin" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Wednesday, August 15, 2001 10:38 PM
Subject: [dom4j-dev] Changed behavior in element(String name) method
I have noticed that in the latest 0.9 patch release which I downloaded
today to correct the SAX validating parser problem, the implementation
of the element(String name) method has changed in the DefaultElement
class. In the previous 0.9 release the method called the getName()
method which returned the local name. According to the javadoc
description of the method("Returns the first element for the given local
name and any namespace") this makes sense. However in the patch release
the getQualifiedName() method is now being called. Is this the intended
functionality? Is this a permanent change? If so I will need to change
quite a bit of code. Cheers!
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