XPath of Node

How to get an XPath from an XML-Node? Is there something like node.getXPath()?

Answer: http://lekkimworld.com/2007/06/19/building_xpath_expression_from_xml_node.html

• Java:

  import java.util.Stack;
  
  import org.w3c.dom.Element;
  import org.w3c.dom.Node;
  
  /**
   * Utility class for dealing with XML DOM elements.
   * 
   * 
   * @author Mikkel Heisterberg, lekkim@lsdoc.org
   */
  public class ElementUtil {
     
     /**
      * Constructs a XPath query to the supplied node.
      * 
      * @param n
      * @return
      */
     public static String getXPath(Node n) {
        // abort early
        if (null == n) return null;
  
        // declarations
        Node parent = null;
        Stack hierarchy = new Stack();
        StringBuffer buffer = new StringBuffer();
  
        // push element on stack
        hierarchy.push(n);
  
        parent = n.getParentNode();
        while (null != parent && parent.getNodeType() != Node.DOCUMENT_NODE) {
           // push on stack
           hierarchy.push(parent);
  
           // get parent of parent
           parent = parent.getParentNode();
        }
  
        // construct xpath
        Object obj = null;
        while (!hierarchy.isEmpty() && null != (obj = hierarchy.pop())) {
           Node node = (Node) obj;
           boolean handled = false;
  
           // only consider elements
           if (node.getNodeType() == Node.ELEMENT_NODE) {
              Element e = (Element) node;
  
              // is this the root element?
              if (buffer.length() == 0) {
                 // root element - simply append element name
                 buffer.append(node.getLocalName());
              } else {
                 // child element - append slash and element name
                 buffer.append("/");
                 buffer.append(node.getLocalName());
                 
                 if (node.hasAttributes()) {
                    // see if the element has a name or id attribute
                    if (e.hasAttribute("id")) {
                       // id attribute found - use that
                       buffer.append("[@id='" + e.getAttribute("id") + "']");
                       handled = true;
                    } else if (e.hasAttribute("name")) {
                       // name attribute found - use that
                       buffer.append("[@name='" + e.getAttribute("name") + "']");
                       handled = true;
                    }
                 }
  
                 if (!handled) {
                    // no known attribute we could use - get sibling index
                    int prev_siblings = 1;
                    Node prev_sibling = node.getPreviousSibling();
                    while (null != prev_sibling) {
                       if (prev_sibling.getNodeType() == node.getNodeType()) {
                          if (prev_sibling.getLocalName().equalsIgnoreCase(node.getLocalName())) {
                             prev_siblings++;
                          }
                       }
                       prev_sibling = prev_sibling.getPreviousSibling();
                    }
                    buffer.append("[" + prev_siblings + "]");
                 }
              }
           }
        }
  
        // return buffer
        return buffer.toString();
     }
  }
  

• Java-Script:

  function GetXPath(GivenNode)
  {
   
   if (null == GivenNode) return null
   
   // declarations -----------------------------------------------
   var TempParent = null
   var Hierarchy = new Array()
   var StringBuffer = ""
   //-------------------------------------------------------------
   
   // push first element on stack
   Hierarchy.push(GivenNode)
   
   // search for all ancestors -----------------------------------
   var TempParent = GivenNode.parentNode
   var TempNode
   var TempSibling
   var PrevSiblings
   var Handled = false
   while (null != TempParent && TempParent.nodeType != Node.DOCUMENT_NODE)
   {
    Hierarchy.push(TempParent)
    TempParent = TempParent.parentNode
   }
   //-------------------------------------------------------------
  
   // construct xpath
   while (!(Hierarchy.length == 0) && null != (TempNode = Hierarchy.pop()))
   {
    Handled = false
    // only consider elements
    if (TempNode.nodeType == Node.ELEMENT_NODE)
    {
              // is this the root element?
     if (StringBuffer.length == 0)
     {
      // root element - simply append element name
      StringBuffer = StringBuffer + TempNode.localName
              }
              else
              {
               // child element - append slash and element name
               StringBuffer = StringBuffer + "/" + TempNode.localName
               if (TempNode.hasAttributes())
               {
                // see if the element has a name or id attribute
                if (TempNode.attributes.getNamedItem("id"))
                {
                 StringBuffer = StringBuffer + "[@id='" + TempNode.attributes.getNamedItem("id").nodeValue + "']"
                 Handled = true
                }
                else if (TempNode.attributes.getNamedItem("name"))
                {
                 StringBuffer = StringBuffer + "[@name='" + TempNode.attributes.getNamedItem("name").nodeValue + "']"
                 Handled = true
                }
               }
               
               if (!Handled)
               {
                // no known attribute we could use - get sibling index
                PrevSiblings = 1
                TempSibling = TempNode.previousSibling
                while (null != TempSibling)
                {
                 if (TempSibling.nodeType == TempNode.nodeType)
                 {
                  if (TempSibling.localName.toLowerCase() == TempNode.localName.toLowerCase())
                  {
                   PrevSiblings++
                  }
                 }
                 TempSibling = TempSibling.previousSibling
                }
                StringBuffer = StringBuffer + "[" + PrevSiblings + "]"
               }
              }
    }
   }
   // return buffer
   return StringBuffer
  }