[jdom-interest] moving namespaces up

[Jason Hunter]

As I told Vladimir in private discussion a minute ago, the
setName/setNamespace methods were introduced post beta6.

-jh-

Vladimir Grishchenko wrote:
> 
> Hi again,
> 
> I spent some time coding to come up with a solution. To my
> disappointment I've discovered there's no setNamespace() method in
> Element, and there's also no setName() which I didn't really need.
> I've read a discussion
> on this mailing list that took place some time ago and kind of see
> why it is so. While not needed in most of the cases I think there's
> nothing wrong with the methods mentioned, at least with the namespace
> one. Without them I'd have to call getCopy() on each element in my tree
> to modify its namespaces prefix, this is really bad performance wise since
> it
> recursively clones the whole subtree under this Element (correct me if
> I'm wrong). What an overkill, I just wanted to change element's namespace
> prefix but have to end up with cloning the tree multiple times. So I went
> and added setNamespace() to both Element and Attribute. Here's a "solution"
> to my problem, may be you can point me to potential pitfalls I could have
> introduced here.
> 
> Thanks,
> --V.
> 
> ---
> 
> import org.jdom.*;
> import org.jdom.output.*;
> 
> import java.util.Map;
> import java.util.HashMap;
> import java.util.List;
> import java.util.ArrayList;
> import java.util.Iterator;
> 
> public class RootNamespaceDocument extends Document
> {
>   private Map namespaces;
>   private List sorted;
> 
>   public RootNamespaceDocument(Document other)
>   {
>     super(other.getRootElement(), other.getDocType());
>     other.setRootElement(null);
>     namespaces = new HashMap(20);
>     sorted = new ArrayList(10);
>     renameNamespaces(getRootElement());
>     Iterator i = sorted.iterator();
>     while (i.hasNext())
>       getRootElement().addNamespaceDeclaration((Namespace) i.next());
>   }
> 
>   private void renameNamespaces(Element root)
>   {
>     Namespace n = root.getNamespace();
>     if (!n.equals(Namespace.NO_NAMESPACE))
>       //had to change org.jdom.Element to do this
>       root.setNamespace(getNewNamespace(n.getURI()));
>     List l = root.getAttributes();
>     Attribute a;
>     for (int i = 0; i < l.size(); i++)
>     {
>       a = (Attribute) l.get(i);
>       n = a.getNamespace();
>       if (!n.equals(Namespace.NO_NAMESPACE))
>         //had to change org.jdom.Attribute to do this
>         a.setNamespace(getNewNamespace(n.getURI()));
>     }
>     l = root.getChildren();
>     for (int i = 0; i < l.size(); i++)
>       renameNamespaces((Element) l.get(i));
>   }
> 
>   private Namespace getNewNamespace(String uri)
>   {
>     Namespace newns = (Namespace) namespaces.get(uri);
>     if (newns == null)
>     {
>       newns = Namespace.getNamespace("ns" + namespaces.size(), uri);
>       namespaces.put(uri, newns);
>       sorted.add(newns);
>     }
>     return newns;
>   }
> 
>   public static void main(String[] args) throws Exception
>   {
>     Namespace ns1 = Namespace.getNamespace("A", "FOO:");
>     Namespace ns2 = Namespace.getNamespace("B", "BAR:");
>     Namespace ns3 = Namespace.getNamespace("C", "BAZ:");
>     Namespace ns4 = Namespace.getNamespace("D", "ZAB:");
>     Namespace ns5 = Namespace.getNamespace("E", "RAB:");
>     Namespace ns6 = Namespace.getNamespace("F", "OOF:");
> 
>     Document d = new Document(new Element("root_element", ns6));
> 
>     d.getRootElement().addContent(new Element("child1", ns1)
>       .addAttribute(new Attribute("xxx", "yyy", ns3)));
>     d.getRootElement().addContent(new Element("child2", ns2)
>       .addAttribute(new Attribute("zzz", "ooo", ns4)));
>     d.getRootElement().addContent(new Element("child3", ns1)
>       .addAttribute(new Attribute("ggg", "hhh", ns2)));
>     XMLOutputter outputter = new XMLOutputter("   ", true);
>     System.out.println("WAS:");
>     outputter.output(d, System.out);
>     RootNamespaceDocument rnd = new RootNamespaceDocument(d);
>     System.out.println("\nNOW:");
>     outputter.output(rnd, System.out);
> 
>   }
> }
> 
> > -----Original Message-----
> > From: Elliotte Rusty Harold [mailto:elharo at metalab.unc.edu]
> > Sent: Friday, June 15, 2001 5:22 PM
> > To: Vladimir Grishchenko; 'jdom-interest at jdom.org'
> > Subject: Re: [jdom-interest] moving namespaces up
> >
> >
> > At 4:28 PM -0700 6/15/01, Vladimir Grishchenko wrote:
> > >Hello,
> > >
> > >Here is a dumb question but I need this functionality for my project.
> > >I looked briefly at JDOM api and couldn't find a way to do
> > the following:
> > >
> > >Say, I have an XML doc stored as:
> > >
> > ><root>
> > >    <A:child1 xmlns:A="FOO:"/>
> > >    <B:child2 xmlns:B="BAR:"/>
> > ></root>
> > >
> > >I read it in via SAXBuilder and I want it to be outputted as:
> > >
> > ><root xmlns:A="FOO:" xmlns:B="BAR:">
> > >   <A:child1/>
> > >   <B:child2/>
> > ><root/>
> > >
> > >Basically I need all namespace declarations to be moved up, possibly
> > >changing prefix names if there's any prefix name collisions.
> > >
> >
> > I doubt this will be a part of the JDOM 1.0 core. We used to do
> > something like this, but then we were convinced that it was
> > impossible to do in the general case because of the difficulty of
> > recognizing when prefixes were and were not used in attribute values
> > and element content.
> > --
> >
> > +-----------------------+------------------------+-------------------+
> > | Elliotte Rusty Harold | elharo at metalab.unc.edu | Writer/Programmer |
> > +-----------------------+------------------------+-------------------+
> > |                  The XML Bible (IDG Books, 1999)                   |
> > |              http://metalab.unc.edu/xml/books/bible/               |
> > |   http://www.amazon.com/exec/obidos/ISBN=0764532367/cafeaulaitA/   |
> > +----------------------------------+---------------------------------+
> > |  Read Cafe au Lait for Java News:  http://metalab.unc.edu/javafaq/ |
> > |  Read Cafe con Leche for XML News: http://metalab.unc.edu/xml/     |
> > +----------------------------------+---------------------------------+
> >
> 
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