code: public XPath createXPath(String str, ElemTemplateElement owningTemplate)
            throws javax.xml.transform.TransformerException
    {
      ErrorListener handler = m_stylesheetProcessor.getErrorListener();
      XPath xpath = new XPath(str, owningTemplate, this, XPath.SELECT, handler, 
              m_funcTable);
      // Visit the expression, registering namespaces for any extension functions it includes.
      xpath.callVisitors(xpath, new ExpressionVisitor(getStylesheetRoot()));
      return xpath;
    }
docs: Process an expression string into an XPath.
  Must be public for access by the AVT class.
  
  @param str A non-null reference to a valid or invalid XPath expression string.
  
  @return A non-null reference to an XPath object that represents the string argument.
  
  @throws javax.xml.transform.TransformerException if the expression can not be processed.
  @see <a href="http://www.w3.org/TR/xslt#section-Expressions">Section 4 Expressions in XSLT Specification</a>