[jdom-interest] JDOM 1.1.2 / Saxon 9.4.0.1: namespace xmlns="" could not be added as a namespace

[Rolf Lear]

Hi Leigh.

I am at my office so I can't debug this issue right now... and
additionally I have not played with Saxon XSLT code.

but, inspecting the JDOM 1.1.2 code it is 'clear' that the Saxon code
triggered the following Sax 'events':


...
// maybe some other startPrefixMapping(..., ...);  
startPrefixMapping("", "");  // indicate that the "" prefix is linked to
the "" URI
startElement("http://example.com/foo", "bar", "bar", attributes);
...


This is a broken chain of SAX events.... it is indicating that the ""
prefix maps to "" (xmlns=""), but then loads the element in the foo
namespace xmlns="http://example.com/foo"

In the particular examples you cite there should be exactly one
startPrefixMapping("", "") call per document and it should happen before
the 'document' start element (or will it be zero calls for "","" since it
is assumed... I forget).

when the new element processes the 'additional' namespace xmlns="" it
finds that the element itself has the "" prefix, but it is mapped to a
different URI. Hence the exception.

Now, as to why this is different in 1.1.2 vs. 1.1.1 I am not sure.... and
that in itself is suspicious....

If you have the code in hand you can more easily debug the issue...
(easier than me right now...).

I can load it up in a few hours time and inspect it too. I suspect that
the issue is a Saxon one, but then why the difference between 1.1.1 and
1.1.2 ... I am not sure.

Rolf



On Tue, 24 Jan 2012 11:26:41 -0800, Leigh L Klotz Jr
<leigh.klotz at xerox.com> wrote:
> Has anyone encountered this? It doesn't happen with JDOM 1.1.1, but it 
> does happen with JDOM 1.1.2.
> 
> Vanilla XSLT transform:
> 
> <?xml version="1.0"?>
> <xsl:transform version="1.0" 
> xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
> <xsl:template match="*|@*|text()">
> <xsl:copy-of select="." />
> </xsl:template>
> </xsl:transform>
> 
> Document with default namespace change and any attribute on the element:

> FAILS:
> 
> <?xml version="1.0" encoding="UTF-8"?>
> <description>
> <foo xmlns="http://example.com/foo">
> <bar x="...">...</bar>
> </foo>
> </description>
> 
> Document with default namespace change and no attribute on the element: 
> WORKS:
> <?xml version="1.0" encoding="UTF-8"?>
> <description>
> <foo xmlns="http://example.com/foo">
> <bar >...</bar>
> </foo>
> </description>
> 
> Here's the error:
> 
> org.jdom.IllegalAddException: The namespace xmlns="" could not be added 
> as a namespace to "bar": The namespace prefix "" collides with the 
> element namespace prefix
>      at org.jdom.Element.addNamespaceDeclaration(Element.java:363)
>      at
org.jdom.input.SAXHandler.transferNamespaces(SAXHandler.java:714)
>      at org.jdom.input.SAXHandler.startElement(SAXHandler.java:563)
>      at 
>
net.sf.saxon.event.ContentHandlerProxy.startContent(ContentHandlerProxy.java:366)
>      at 
>
net.sf.saxon.event.NamespaceReducer.startContent(NamespaceReducer.java:192)
>      at 
>
net.sf.saxon.event.ComplexContentOutputter.startContent(ComplexContentOutputter.java:583)
>      at 
> net.sf.saxon.tree.tiny.TinyElementImpl.copy(TinyElementImpl.java:350)
>      at 
> net.sf.saxon.expr.instruct.CopyOf.processLeavingTail(CopyOf.java:510)
>      at 
> net.sf.saxon.expr.instruct.Template.applyLeavingTail(Template.java:212)
>      at net.sf.saxon.trans.Mode.applyTemplates(Mode.java:1032)
>      at 
>
net.sf.saxon.trans.TextOnlyCopyRuleSet.process(TextOnlyCopyRuleSet.java:58)
>      at net.sf.saxon.trans.Mode.applyTemplates(Mode.java:1020)
>      at net.sf.saxon.Controller.transformDocument(Controller.java:1957)
>      at net.sf.saxon.Controller.transform(Controller.java:1803)
>      at 
> net.sf.saxon.s9api.XsltTransformer.transform(XsltTransformer.java:430)
> 
> 
> I'm using this code fragment to tell Saxon9 to serialize to JDOM:
> 
>    import net.sf.saxon.s9api.SAXDestination;
>    import org.jdom.input.SAXHandler;
>    import net.sf.saxon.s9api.Destination;
> 
>    SAXHandler saxHandler = new SAXHandler();
>    Destination saxDestination = new SAXDestination(saxHandler);
>    xsltTransformer.setSource(new JDOMSource(document));
>    xsltTransformer.setDestination(saxDestination);
>    xsltTransformer.transform();
> 
> If this isn't a JDOM bug, then I guess it must be a Saxon one.
> 
> Leigh.
> 
> _______________________________________________
> To control your jdom-interest membership:
> http://www.jdom.org/mailman/options/jdom-interest/youraddr@yourhost.com