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.Node;
import org.w3c.dom.DOMException;


The XPathExpression interface represents a parsed and resolved 
XPath expression.

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

/**
 * The <code>XPathExpression</code> interface represents a parsed and resolved 
 * XPath expression.
 * <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 XPathExpression {
    
Evaluates this XPath expression and returns a result.

Params:
  • contextNode – The context is context node for the 
  evaluation of this XPath expression.If the XPathEvaluator was 
  obtained by casting the Document then this must be 
  owned by the same document and must be a Document, 
  Element, Attribute, Text, 
  CDATASection, Comment, 
  ProcessingInstruction, or XPathNamespace 
  node.If the context node is a Text or a 
  CDATASection, then the context is interpreted as the 
  whole logical text node as seen by XPath, unless the node is empty 
  in which case it may not serve as the XPath context.
  • type – If a specific type is specified, then the 
  result will be coerced to return the specified type relying on 
  XPath conversions and fail if the desired coercion is not possible. 
  This must be one of the type codes of XPathResult.
  • result – The result specifies a specific result 
  object which may be reused and returned by this method. If this is 
  specified as nullor the implementation does not reuse 
  the specified result, a new result object will be constructed and 
  returned.For XPath 1.0 results, this object will be of type 
  XPathResult.
Throws:
  • XPathException – 
  TYPE_ERR: Raised if the result cannot be converted to return the 
  specified type.
  • DOMException – 
  WRONG_DOCUMENT_ERR: The Node is from a document that is not supported 
  by the XPathEvaluator that created this XPathExpression
  .
  
    NOT_SUPPORTED_ERR: The Node is not a type permitted as an XPath 
  context node or the request type is not permitted by this 
  XPathExpression.
Returns:The result of the evaluation of the XPath expression.For XPath 
  1.0 results, this object will be of type XPathResult.
/**
     * Evaluates this XPath expression and returns a result.
     * @param contextNode The <code>context</code> is context node for the 
     *   evaluation of this XPath expression.If the XPathEvaluator was 
     *   obtained by casting the <code>Document</code> then this must be 
     *   owned by the same document and must be a <code>Document</code>, 
     *   <code>Element</code>, <code>Attribute</code>, <code>Text</code>, 
     *   <code>CDATASection</code>, <code>Comment</code>, 
     *   <code>ProcessingInstruction</code>, or <code>XPathNamespace</code> 
     *   node.If the context node is a <code>Text</code> or a 
     *   <code>CDATASection</code>, then the context is interpreted as the 
     *   whole logical text node as seen by XPath, unless the node is empty 
     *   in which case it may not serve as the XPath context.
     * @param type If a specific <code>type</code> is specified, then the 
     *   result will be coerced to return the specified type relying on 
     *   XPath conversions and fail if the desired coercion is not possible. 
     *   This must be one of the type codes of <code>XPathResult</code>.
     * @param result The <code>result</code> specifies a specific result 
     *   object which may be reused and returned by this method. If this is 
     *   specified as <code>null</code>or the implementation does not reuse 
     *   the specified result, a new result object will be constructed and 
     *   returned.For XPath 1.0 results, this object will be of type 
     *   <code>XPathResult</code>.
     * @return The result of the evaluation of the XPath expression.For XPath 
     *   1.0 results, this object will be of type <code>XPathResult</code>.
     * @exception XPathException
     *   TYPE_ERR: Raised if the result cannot be converted to return the 
     *   specified type.
     * @exception DOMException
     *   WRONG_DOCUMENT_ERR: The Node is from a document that is not supported 
     *   by the XPathEvaluator that created this <code>XPathExpression</code>
     *   .
     *   <br>NOT_SUPPORTED_ERR: The Node is not a type permitted as an XPath 
     *   context node or the request type is not permitted by this 
     *   <code>XPathExpression</code>.
     */
    public Object evaluate(Node contextNode, 
                           short type, 
                           Object result)
                           throws XPathException, DOMException;

}