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Find all namespace declarations in an XML document - xPath 1.0 vs xPath 2.0

As part of a Java 6 application, I want to find all namespace declarations in an XML document, including any duplicates.

Edit : for Martin, here we use the Java code that I use:

XPathFactory xPathFactory = XPathFactory.newInstance();
XPath xPath = xPathFactory.newXPath();
XPathExpression xPathExpression = xPathExpression = xPath.compile("//namespace::*"); 
NodeList nodeList = (NodeList) xPathExpression.evaluate(xmlDomDocument, XPathConstants.NODESET);

Suppose I have this XML document:

<?xml version="1.0" encoding="UTF-8"?>
<root xmlns:ele="element.com" xmlns:att="attribute.com" xmlns:txt="textnode.com">
    <ele:one>a</ele:one>
    <two att:c="d">e</two>
    <three>txt:f</three>
</root>

To find all namespace declarations, I applied this xPath operator to an XML document using xPath 1.0 :

//namespace::*

It finds 4 namespace declarations that I expect (and wish):

/root[1]/@xmlns:att - attribute.com
/root[1]/@xmlns:ele - element.com
/root[1]/@xmlns:txt - textnode.com
/root[1]/@xmlns:xml - http://www.w3.org/XML/1998/namespace

But if I switch to using xPath 2.0 , I get 16 namespace declarations (each of the previous declarations 4 times), which is not what I expect (or wish):

/root[1]/@xmlns:xml - http://www.w3.org/XML/1998/namespace
/root[1]/@xmlns:att - attribute.com
/root[1]/@xmlns:ele - element.com
/root[1]/@xmlns:txt - textnode.com
/root[1]/@xmlns:xml - http://www.w3.org/XML/1998/namespace
/root[1]/@xmlns:att - attribute.com
/root[1]/@xmlns:ele - element.com
/root[1]/@xmlns:txt - textnode.com
/root[1]/@xmlns:xml - http://www.w3.org/XML/1998/namespace
/root[1]/@xmlns:att - attribute.com
/root[1]/@xmlns:ele - element.com
/root[1]/@xmlns:txt - textnode.com
/root[1]/@xmlns:xml - http://www.w3.org/XML/1998/namespace
/root[1]/@xmlns:att - attribute.com
/root[1]/@xmlns:ele - element.com
/root[1]/@xmlns:txt - textnode.com

, xPath:

/descendant-or-self::node()/namespace::*

XML (LIBXML, MSXML.NET, Saxon), oXygen. ( : , . , XML, .)

№ 1: xPath 1.0 xPath 2.0?

№ 2: / xPath 2.0?

: distinct-values() xPath 2.0 , , , . , XML-:

<?xml version="1.0" encoding="UTF-8"?>
<root>
    <bar:one xmlns:bar="http://www.bar.com">alpha</bar:one>
    <bar:two xmlns:bar="http://www.bar.com">bravo</bar:two>
</root>

:

/root[1]/@xmlns:xml - http://www.w3.org/XML/1998/namespace
/root[1]/bar:one[1]/@xmlns:bar - http://www.bar.com
/root[1]/bar:two[1]/@xmlns:bar - http://www.bar.com
+3
4

, , - :

for $i in 1 to count(//namespace::*) return 
if (empty(index-of((//namespace::*)[position() = (1 to ($i - 1))][name() = name((//namespace::*)[$i])], (//namespace::*)[$i]))) 
then (//namespace::*)[$i] 
else ()
+7

, xPath XML- xPath 1.0:

//namespace::* It finds 4 namespace declarations, which is what I expect (and desire):

/root[1]/@xmlns:att - attribute.com
/root[1]/@xmlns:ele - element.com 
/root[1]/@xmlns:txt - textnode.com 
/root[1]/@xmlns:xml - http://www.w3.org/XML/1998/namespace

() XPath 1.0.

XSLT 1.0, . ( XPath node):

<xsl:stylesheet version="1.0"
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:xs="http://www.w3.org/2001/XMLSchema">
    <xsl:output omit-xml-declaration="yes" indent="yes"/>

 <xsl:template match="/">
     <xsl:for-each select="//namespace::*">
       <xsl:value-of select="concat(name(), ': ', ., '&#xA;')"/>
     </xsl:for-each>
 </xsl:template>
</xsl:stylesheet>

XML-:

<root xmlns:ele="element.com" xmlns:att="attribute.com" xmlns:txt="textnode.com">
    <ele:one>a</ele:one>
    <two att:c="d">e</two>
    <three>txt:f</three>
</root>

:

xml: http://www.w3.org/XML/1998/namespace
ele: element.com
att: attribute.com
txt: textnode.com
xml: http://www.w3.org/XML/1998/namespace
ele: element.com
att: attribute.com
txt: textnode.com
xml: http://www.w3.org/XML/1998/namespace
ele: element.com
att: attribute.com
txt: textnode.com
xml: http://www.w3.org/XML/1998/namespace
ele: element.com
att: attribute.com
txt: textnode.com

XSLT 1.0 XSLT 2.0:

MSXML3, MSXML4, MSXML6,.NET XslCompiledTransform,.NET XslTransform, Altova (XML SPY), Saxon 6.5.4, Saxon 9.1.07, XQSharp.

#, , .NET, 16:

namespace TestNamespaces
{
    using System;
    using System.IO;
    using System.Xml.XPath;

    class Test
    {
        static void Main(string[] args)
        {
            string xml =
@"<root xmlns:ele='element.com' xmlns:att='attribute.com' xmlns:txt='textnode.com'>
    <ele:one>a</ele:one>
    <two att:c='d'>e</two>
    <three>txt:f</three>
</root>";
            XPathDocument doc = new XPathDocument(new StringReader(xml));

            double count = 
              (double) doc.CreateNavigator().Evaluate("count(//namespace::*)");

            Console.WriteLine(count);
        }
    }
}

:

16.

UPDATE

XPath 2.0, "" -:

for $i in distinct-values(
             for $ns in //namespace::*
               return
                  index-of(
                           (for $x in //namespace::*
                             return
                                concat(name($x), ' ', string($x))

                            ),
                            concat(name($ns), ' ', string($ns))
                          )
                          [1]
                                                  )
  return
    for $x in (//namespace::*)[$i]
     return
        concat(name($x), ' :', string($x), '&#xA;')
+4

, //namespace::* , 16, XPath 1.0 XPath 2.0. , , .

( ) XPath 1.0 XPath 2.0, :

A:

<a xmlns="one">
  <b/>
</a>

B:

<a xmlns="one">
  <b xmlns="one"/>
</a>

" " , , , XPath 2.0:

for $e in //* return
  for $n in $e/namespace::* return
     if (not(some $p in $n/../namespace::* satisfies ($p/name() eq $e/name() and string($p) eq string($n)))) then concat($e/name(), '->', $n/name(), '=', string($n)) else ()
+3

, XPath 1.0.NET XPathDocument ( XSLT/XPath 1.0), XmlDocument ( DOM) MSXML 6 DOM; , XML-,

    Console.WriteLine("XPathDocument:");
    XPathDocument xpathDoc = new XPathDocument("../../XMLFile4.xml");
    foreach (XPathNavigator nav in xpathDoc.CreateNavigator().Select("//namespace::*"))
    {
        Console.WriteLine("Node type: {0}; name: {1}; value: {2}.", nav.NodeType, nav.Name, nav.Value);
    }
    Console.WriteLine();

    Console.WriteLine("DOM XmlDocument:");
    XmlDocument doc = new XmlDocument();
    doc.Load("../../XMLFile4.xml");
    foreach (XmlNode node in doc.SelectNodes("//namespace::*"))
    {
        Console.WriteLine("Node type: {0}; name: {1}; value: {2}.", node.NodeType, node.Name, node.Value);
    }
    Console.WriteLine();


    Console.WriteLine("MSXML 6 DOM:");
    dynamic msxmlDoc = Activator.CreateInstance(Type.GetTypeFromProgID("Msxml2.DOMDocument.6.0"));
    msxmlDoc.load("../../XMLFile4.xml");
    foreach (dynamic node in msxmlDoc.selectNodes("//namespace::*"))
    {
        Console.WriteLine("Node type: {0}; name: {1}; value: {2}.", node.nodeType, node.name, node.nodeValue);
    }


XPathDocument:
Node type: Namespace; name: txt; value: textnode.com.
Node type: Namespace; name: att; value: attribute.com.
Node type: Namespace; name: ele; value: element.com.
Node type: Namespace; name: xml; value: http://www.w3.org/XML/1998/namespace.
Node type: Namespace; name: txt; value: textnode.com.
Node type: Namespace; name: att; value: attribute.com.
Node type: Namespace; name: ele; value: element.com.
Node type: Namespace; name: xml; value: http://www.w3.org/XML/1998/namespace.
Node type: Namespace; name: txt; value: textnode.com.
Node type: Namespace; name: att; value: attribute.com.
Node type: Namespace; name: ele; value: element.com.
Node type: Namespace; name: xml; value: http://www.w3.org/XML/1998/namespace.
Node type: Namespace; name: txt; value: textnode.com.
Node type: Namespace; name: att; value: attribute.com.
Node type: Namespace; name: ele; value: element.com.
Node type: Namespace; name: xml; value: http://www.w3.org/XML/1998/namespace.

DOM XmlDocument:
Node type: Attribute; name: xmlns:txt; value: textnode.com.
Node type: Attribute; name: xmlns:att; value: attribute.com.
Node type: Attribute; name: xmlns:ele; value: element.com.
Node type: Attribute; name: xmlns:xml; value: http://www.w3.org/XML/1998/namespa
ce.
Node type: Attribute; name: xmlns:txt; value: textnode.com.
Node type: Attribute; name: xmlns:att; value: attribute.com.
Node type: Attribute; name: xmlns:ele; value: element.com.
Node type: Attribute; name: xmlns:xml; value: http://www.w3.org/XML/1998/namespa
ce.
Node type: Attribute; name: xmlns:txt; value: textnode.com.
Node type: Attribute; name: xmlns:att; value: attribute.com.
Node type: Attribute; name: xmlns:ele; value: element.com.
Node type: Attribute; name: xmlns:xml; value: http://www.w3.org/XML/1998/namespa
ce.
Node type: Attribute; name: xmlns:txt; value: textnode.com.
Node type: Attribute; name: xmlns:att; value: attribute.com.
Node type: Attribute; name: xmlns:ele; value: element.com.
Node type: Attribute; name: xmlns:xml; value: http://www.w3.org/XML/1998/namespa
ce.

MSXML 6 DOM:
Node type: 2; name: xmlns:xml; value: http://www.w3.org/XML/1998/namespace.
Node type: 2; name: xmlns:ele; value: element.com.
Node type: 2; name: xmlns:att; value: attribute.com.
Node type: 2; name: xmlns:txt; value: textnode.com.
Node type: 2; name: xmlns:xml; value: http://www.w3.org/XML/1998/namespace.
Node type: 2; name: xmlns:ele; value: element.com.
Node type: 2; name: xmlns:att; value: attribute.com.
Node type: 2; name: xmlns:txt; value: textnode.com.
Node type: 2; name: xmlns:xml; value: http://www.w3.org/XML/1998/namespace.
Node type: 2; name: xmlns:ele; value: element.com.
Node type: 2; name: xmlns:att; value: attribute.com.
Node type: 2; name: xmlns:txt; value: textnode.com.
Node type: 2; name: xmlns:xml; value: http://www.w3.org/XML/1998/namespace.
Node type: 2; name: xmlns:ele; value: element.com.
Node type: 2; name: xmlns:att; value: attribute.com.
Node type: 2; name: xmlns:txt; value: textnode.com.

Therefore, this is not a problem with XPath 1.0 and XPath 2.0. I think the problem you are seeing is a flaw in comparing the XPath data model with the namespace nodes with the DOM model with the attribute nodes. Someone more familiar with the Java XPath API should tell you whether the behavior you see is implementation dependent, as the API specification is not accurate enough to match the XPath namespace axis with the DOM, or if this is an error.

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