[jdom-interest] Namespace issues, et al.

[bob mcwhirter]

It's not a matter of -changing- a namespace.

	Element e = new Element( "Envelope", soapNs );

That definitively creates a soap envelope element regardless
of the context it ends up being attached.  I don't have to
worry about making sure it's within something that sets 
a namespace one way or the other.

	Element e = new Element( "Envelope" );

So, using -your- idea:

...If I glue it into a SOAP document in the right place,
it might end up being a SOAP envelope.  If I glue it in at
a different place in different document it might become
a paper-goods envelope.  To me, that radically chages the
semantics of the element.  And the semantics of the element
should be fixed/deterministic.  

If you want a SOAP envelope, then make a SOAP envelope.
If you want a paper-goods envelope, then make a paper-goods
envelope.

The semantics of an Element should not be contingent upon
it's surrounding context.  This is a -feature- not a -bug-.

	-bob


On Sun, 23 Feb 2003, Malachi de AElfweald wrote:

> Yes, I understand that now.... but I still don't agree with it.
> The reason is that doing it that way means that, if I want to say
> "use the same Namespace", I have to pass a namespace to the constructor.
> If I want to use a different one than the parent (ie: "" instead of 
> whatever
> it actually is), then I DON'T pass it into the constructor.  The logic is
> backwards.
> 
> Ie:
> CURRENT:
> 	new Element(name) -> change namespace to ""
> 	new Element(name, NS) -> change namespace to NS
> 
> SHOULD BE:
> 	new Element(name) -> don't change namespace at all
> 	new Element(name, NS) -> change namespace to NS
> 
> Don't get me wrong. I think JDOM is the best XML API I have ever used.
> However,  it is non-intuitive to say "Don't pass a Namespace in the 
> constructor
> means CHANGE namespace"... It should be "Don't pass a Namespace in the 
> constructor
> means DON'T CHANGE namespace"...
> 
> Malachi
> 
> On Sun, 23 Feb 2003 22:36:11 -0600, Bradley S. Huffman 
> <hip at a.cs.okstate.edu> wrote:
> 
> > Malachi de AElfweald writes:
> >
> >> The issue was 2-fold. If I created them with the xmlns in the 
> >> constructor, I was
> >> also setting the xsi:schemaLocation attribute on it again -- thus the 
> >> first problem.
> >> The second part of it was that I assumed (since textually it is true) 
> >> that putting
> >> a tag inside another (like tagA above) inherits the namespace of the 
> >> parent element.
> >> This is true in XML, and is true in the textual representation -- but 
> >> JDOM changes the
> >> textual representation to break it... Thus, it can not inherit 
> >> namespaces from the parent
> >> because of the fact xmlns="" is being added without my consent. If that 
> >> one piece was not
> >> added, then it would all inherit correctly.
> >
> > JDOM does not change anything.  If you run you text through SAXBuilder,
> > JDOM will build a faithful representation of it with JDOM objects 
> > (Element,
> > Document, DocType, EntityRef, Namespace, and such). It will not change,
> > add, or delete any information. The problem seems to be you are creating
> > new objects and adding them to the treewhcih was built from your texual
> > representation and it's not producing what you think it should.
> >
> > Let take a simple example, running the following text though SAXBuilder
> >
> > <root xmlns="my.default.namespace">
> > <child1/>
> > <child2/>
> > </root>
> >
> > Produces the same objects as the following JDOM code
> >
> > Namespace defaultNS = Namespace.get("my.default.namespace");
> > Element root = new Element("root", defaultNS);
> > Text text1 = new Text("\n  ");
> > Element child1 = new Element("child1", defaultNS);
> > Text text2 = new Text("\n  ");
> > Element child2 = new Element("child2", defaultNS);
> > Text text3 = new Text("\n");
> >
> > root.addContent(text1);
> > root.addContent(child1);
> > root.addContent(text2);
> > root.addContent(child2);
> > root.addContent(text3);
> >
> > Document document = new Document(root);
> >
> > Now if you do a
> >
> > Element child3 = new Element("child3");
> >
> > Which is just shorthand for
> >
> > Element child3 = new Element("child3", Namespace.NO_NAMESPACE);
> >
> > It produces a new Element object such that
> >
> > child3.getName()            returns "child3"
> > child3.getNamespacePrefix() returns ""
> > child3.getNamespaceURI()    returns ""
> >
> > Then adding it to root Element object above
> >
> > root.addContent(child3);
> >
> > Means
> >
> > child3.getName()            still returns "child3"
> > child3.getNamespacePrefix() still returns ""
> > child3.getNamespaceURI()    still returns "", not "my.default.namespace"
> >
> > And running document through XMLOutputter (without setting newlines
> > or indent) produces
> >
> > <root xmlns="my.default.namespace">
> > <child1/>
> > <child2/>
> > <child3 xmlns=""/></root>
> >
> > If you really want the textual representation to be
> >
> > <root xmlns="my.default.namespace">
> > <child1/>
> > <child2/>
> > <child3/></root>
> >
> > i.e child3 is in the "my.default.namespace" namespace, then it should of
> > been constructed as follows
> >
> > Element child3 = new Element("child3", defaultNS);
> >
> > Again JDOM does not change anything unless explicitly told to do so.
> >
> > Brad
> >
> >
> 
> 
> 
> -- 
>  
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--
Bob McWhirter        bob at werken.com
The Werken Company   http://werken.com/