http://xml.apache.org/commons/components/external/: xml-commons provides an Apache-hosted set of DOM, SAX, and JAXP interfaces for use in other xml-based projects. Our hope is that we can standardize on both a common version and packaging scheme for these critical XML standards interfaces to make the lives of both our developers and users easier. The External Components portion of xml-commons contains interfaces that are defined by external standards organizations. For DOM, that's the W3C; for SAX it's David Megginson and sax.sourceforge.net; for JAXP it's Sun. 
/*
 * Copyright (c) 2004 World Wide Web Consortium,
 *
 * (Massachusetts Institute of Technology, European Research Consortium for
 * Informatics and Mathematics, Keio University). All Rights Reserved. This
 * work is distributed under the W3C(r) Software License [1] in the hope that
 * it will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 * [1] http://www.w3.org/Consortium/Legal/2002/copyright-software-20021231
 */

package org.w3c.dom.xpath;

import org.w3c.dom.Element;
import org.w3c.dom.Node;


The XPathNamespace interface is returned by 
XPathResult interfaces to represent the XPath namespace node 
type that DOM lacks. There is no public constructor for this node type. 
Attempts to place it into a hierarchy or a NamedNodeMap result in a 
DOMException with the code HIERARCHY_REQUEST_ERR
. This node is read only, so methods or setting of attributes that would 
mutate the node result in a DOMException with the code 
NO_MODIFICATION_ALLOWED_ERR.

The core specification describes attributes of the Node 
interface that are different for different node types but does not 
describe XPATH_NAMESPACE_NODE, so here is a description of 
those attributes for this node type. All attributes of Node 
not described in this section have a null or 
false value.

ownerDocument matches the ownerDocument of the 
ownerElement even if the element is later adopted.

nodeName is always the string "#namespace".

prefix is the prefix of the namespace represented by the 
node.

localName is the same as prefix.

nodeType is equal to XPATH_NAMESPACE_NODE.

namespaceURI is the namespace URI of the namespace 
represented by the node.

nodeValue is the same as namespaceURI.

adoptNode, cloneNode, and 
importNode fail on this node type by raising a 
DOMException with the code NOT_SUPPORTED_ERR.

Note: In future versions of the XPath specification, the 
definition of a namespace node may be changed incomatibly, in which case 
incompatible changes to field values may be required to implement 
versions beyond XPath 1.0.

See also the Document Object Model (DOM) Level 3 XPath Specification.

/**
 * The <code>XPathNamespace</code> interface is returned by 
 * <code>XPathResult</code> interfaces to represent the XPath namespace node 
 * type that DOM lacks. There is no public constructor for this node type. 
 * Attempts to place it into a hierarchy or a NamedNodeMap result in a 
 * <code>DOMException</code> with the code <code>HIERARCHY_REQUEST_ERR</code>
 * . This node is read only, so methods or setting of attributes that would 
 * mutate the node result in a DOMException with the code 
 * <code>NO_MODIFICATION_ALLOWED_ERR</code>.
 * <p>The core specification describes attributes of the <code>Node</code> 
 * interface that are different for different node types but does not 
 * describe <code>XPATH_NAMESPACE_NODE</code>, so here is a description of 
 * those attributes for this node type. All attributes of <code>Node</code> 
 * not described in this section have a <code>null</code> or 
 * <code>false</code> value.
 * <p><code>ownerDocument</code> matches the <code>ownerDocument</code> of the 
 * <code>ownerElement</code> even if the element is later adopted.
 * <p><code>nodeName</code> is always the string "<code>#namespace</code>".
 * <p><code>prefix</code> is the prefix of the namespace represented by the 
 * node.
 * <p><code>localName</code> is the same as <code>prefix</code>.
 * <p><code>nodeType</code> is equal to <code>XPATH_NAMESPACE_NODE</code>.
 * <p><code>namespaceURI</code> is the namespace URI of the namespace 
 * represented by the node.
 * <p><code>nodeValue</code> is the same as <code>namespaceURI</code>.
 * <p><code>adoptNode</code>, <code>cloneNode</code>, and 
 * <code>importNode</code> fail on this node type by raising a 
 * <code>DOMException</code> with the code <code>NOT_SUPPORTED_ERR</code>.
 * <p ><b>Note:</b> In future versions of the XPath specification, the 
 * definition of a namespace node may be changed incomatibly, in which case 
 * incompatible changes to field values may be required to implement 
 * versions beyond XPath 1.0.
 * <p>See also the <a href='http://www.w3.org/TR/2004/NOTE-DOM-Level-3-XPath-20040226'>Document Object Model (DOM) Level 3 XPath Specification</a>.
 */
public interface XPathNamespace extends Node {
    // XPathNodeType
    
The node is a Namespace.

/**
     * The node is a <code>Namespace</code>.
     */
    public static final short XPATH_NAMESPACE_NODE      = 13;

    
The Element on which the namespace was in scope when it 
was requested. This does not change on a returned namespace node even 
if the document changes such that the namespace goes out of scope on 
that element and this node is no longer found there by XPath.

/**
     * The <code>Element</code> on which the namespace was in scope when it 
     * was requested. This does not change on a returned namespace node even 
     * if the document changes such that the namespace goes out of scope on 
     * that element and this node is no longer found there by XPath.
     */
    public Element getOwnerElement();

}