/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 2000 The Apache Software Foundation.  All rights 
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:  
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Xalan" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written 
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation and was
 * originally based on software copyright (c) 1999, Lotus
 * Development Corporation., http://www.lotus.com.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

package org.apache.xalan.lib;

import org.w3c.dom.Node;
import org.w3c.dom.Document;
import org.w3c.dom.DocumentFragment;
import org.w3c.dom.NodeList;
import org.w3c.dom.Text;
import org.w3c.dom.traversal.NodeIterator;
import org.apache.xpath.NodeSet;
import org.apache.xpath.objects.XObject;
import org.apache.xpath.objects.XBoolean;
import org.apache.xpath.objects.XNumber;
import org.apache.xpath.XPath;
import org.apache.xpath.XPathContext;
import org.apache.xpath.DOMHelper;
import org.xml.sax.SAXNotSupportedException;
import java.util.Hashtable;
import java.util.StringTokenizer;

import org.apache.xalan.extensions.ExpressionContext;

/**
 * <meta name="usage" content="general"/>
 * This class contains many of the Xalan-supplied extensions.
 * It is accessed by specifying a namespace URI as follows:
 * <pre>
 *    xmlns:xalan="http://xml.apache.org/xalan"
 * </pre>
 */

public class Extensions {

  private Extensions() {}	// Make sure class cannot be instantiated

//  /**
//   * This method is an extension that implements as a Xalan extension
//   * the node-set function also found in xt and saxon.
//   * If the argument is a Result Tree Fragment, then <code>nodeset</code>
//   * returns a node-set consisting of a single root node as described in
//   * section 11.1 of the XSLT 1.0 Recommendation.  If the argument is a 
//   * node-set, <code>nodeset</code> returns a node-set.  If the argument
//   * is a string, number, or boolean, then <code>nodeset</code> returns
//   * a node-set consisting of a single root node with a single text node
//   * child that is the result of calling the XPath string() function on the 
//   * passed parameter.  If the argument is anything else, then a node-set
//   * is returned consisting of a single root node with a single text node
//   * child that is the result of calling the java <code>toString()</code>
//   * method on the passed argument.
//   * Most of the
//   * actual work here is done in <code>MethodResolver</code> and
//   * <code>XRTreeFrag</code>.
//   * @param myProcessor Context passed by the extension processor
//   * @param rtf Argument in the stylesheet to the nodeset extension function
//   */
//
//  public static NodeSet nodeset(ExpressionContext myProcessor, Object rtf) {
//
//    String textNodeValue;
//
//    if (rtf instanceof NodeIterator)
//    {
//      return new NodeSet((NodeIterator) rtf);
//    }
//    else
//    {
//      if (rtf instanceof String)
//      {
//        textNodeValue = (String) rtf;
//      }
//      else if (rtf instanceof Boolean)
//      {
//        textNodeValue = new XBoolean(((Boolean) rtf).booleanValue()).str();
//      }
//      else if (rtf instanceof Double)
//      {
//        textNodeValue = new XNumber(((Double) rtf).doubleValue()).str();
//      }
//      else
//      {
//        textNodeValue = rtf.toString();
//      }
//      Document myDoc = myProcessor.getContextNode().getOwnerDocument();
//      Text textNode = myDoc.createTextNode(textNodeValue);
//      DocumentFragment docFrag = myDoc.createDocumentFragment();
//      docFrag.appendChild(textNode);
//      return new NodeSet(docFrag);
//    }
//  }
//  
//	/**
//	 * Returns the intersection of two node-sets.
//	 * @param n1 NodeIterator for first node-set
//	 * @param ni2 NodeIterator for second node-set
//	 * @return a NodeSet containing the nodes in ni1 that are also
//	 * in ni2
//	 */	
//	public static NodeSet intersection(NodeIterator ni1, NodeIterator ni2)
//			throws javax.xml.transform.TransformerException
//	{
//		NodeSet ns1 = new NodeSet(ni1);
//		NodeSet ns2 = new NodeSet(ni2);
//		NodeSet inter= new NodeSet();
//		inter.setShouldCacheNodes(true);
//		for (int i=0; i < ns1.getLength(); i++)
//		{
//			Node n = ns1.elementAt(i);
//			if(ns2.contains(n))
//				inter.addElement(n);
//		}
//		return inter;
//	}
//	
//	/**
//	 * Returns the difference between two node-sets.
//	 * @param n1 NodeIterator for first node-set
//	 * @param ni2 NodeIterator for second node-set
//	 * @return a NodeSet containing the nodes in ni1 that are not
//	 * in ni2
//	 */	
//	public static NodeSet difference(NodeIterator ni1, NodeIterator ni2)
//			throws javax.xml.transform.TransformerException	
//	{
//		NodeSet ns1 = new NodeSet(ni1);
//		NodeSet ns2 = new NodeSet(ni2);
//		// NodeSet inter= new NodeSet();
//		NodeSet diff = new NodeSet();
//		diff.setShouldCacheNodes(true);		
//		for (int i = 0; i < ns1.getLength(); i++)
//		{
//			Node n = ns1.elementAt(i);
//			if(!ns2.contains(n))
//				diff.addElement(n);
//		}
//		return diff;
//	}
//
//	/**
//	 * Returns node-set containing distinct string values.
//	 * @param ni NodeIterator for node-set
//	 * @return a NodeSet with nodes from ni containing distinct string values. 
//	 * In other words, if more than one node in ni contains the same string value, 
//	 * only include the first such node found.
//	 */	
//	public static NodeSet distinct(NodeIterator ni)
//			throws javax.xml.transform.TransformerException	
//	{
//		NodeSet ns = new NodeSet(ni);
//		NodeSet dist = new NodeSet();
//		dist.setShouldCacheNodes(true);		
//		Hashtable stringTable = new Hashtable();
//		for (int i = 0; i < ns.getLength(); i++)
//		{
//			Node n = ns.elementAt(i);
//      String key = DOMHelper.getNodeData(n);
//      if (!stringTable.containsKey(key))
//			{
//        stringTable.put(key, n);
//        dist.addElement(n);
//			}
//		}
//		return dist;
//	}
//
//	/**
//	 * Returns true of both node-sets contain the same set of nodes.
//	 * @param n1 NodeIterator for first node-set
//	 * @param ni2 NodeIterator for second node-set
//	 * @return true if ni1 and ni2 contain exactly the same set of nodes.
//	 */	
//	public static boolean hasSameNodes(NodeIterator ni1, NodeIterator ni2)
//	{
//		NodeSet ns1 = new NodeSet(ni1);
//		NodeSet ns2 = new NodeSet(ni2);		
//		if (ns1.getLength() != ns2.getLength())
//			return false;
//		for (int i = 0; i < ns1.getLength(); i++)
//		{
//			Node n = ns1.elementAt(i);
//			if(!ns2.contains(n))
//				return false;
//		}
//		return true;
//	}  
//
//	/**
//	 * Returns the result of evaluating the argument as a string containing
//   * an XPath expression.  Used where the XPath expression is not known until
//   * run-time.  The expression is evaluated as if the run-time value of the
//   * argument appeared in place of the evaluate function call at compile time.
//	 * @param myContext an <code>ExpressionContext</code> passed in by the
//   *                  extension mechanism.  This must be an XPathContext.
//	 * @param xpathExtr The XPath expression to be evaluated.
//	 * @return the XObject resulting from evaluating the XPath
//	 */	
//	public static XObject evaluate(ExpressionContext myContext, String xpathExpr)
//                  throws SAXNotSupportedException, Exception
//	{
//    if (myContext instanceof XPathContext)
//    {
//      try
//      {
//        XPathContext xctxt = (XPathContext) myContext;
//        XPath dynamicXPath = new XPath(xpathExpr,
//                                  xctxt.getSAXLocator(),
//                                  xctxt.getNamespaceContext(),
//                                  XPath.SELECT);
//        return dynamicXPath.execute(xctxt,
//                                    myContext.getContextNode(),
//                                    xctxt.getNamespaceContext());
//      }
//      catch (Exception e)
//      {
//        throw e;
//      }
//    }
//    else
//      throw new SAXNotSupportedException("Invalid context passed to evaluate " + myContext);
//	}  
//
//	/**
//	 * Returns a NodeSet containing one text node for each token in the first argument.
//   * Delimiters are specified in the second argument.
//   * Tokens are determined by a call to <code>StringTokenizer</code>.
//   * If the first argument is an empty string or contains only delimiters, the result
//   * will be an empty NodeSet.
//   * Contributed to XalanJ1 by <a href="mailto:benoit.cerrina@writeme.com">Benoit Cerrina</a>.  
//	 * @param myContext an <code>ExpressionContext</code> passed in by the
//   *                  extension mechanism.  This must be an XPathContext.
//	 * @param toTokenize The string to be split into text tokens.
//   * @param delims The delimiters to use.
//	 * @return a NodeSet as described above.
//   *
//	 */	
//	public static NodeSet tokenize(ExpressionContext myContext, String toTokenize, String delims)
//	{
//    Document lDoc = myContext.getContextNode().getOwnerDocument();
//    StringTokenizer lTokenizer = new StringTokenizer(toTokenize, delims);
//    NodeSet resultSet = new NodeSet();
//    while (lTokenizer.hasMoreTokens())
//    {
//      resultSet.addNode(lDoc.createTextNode(lTokenizer.nextToken()));
//    }
//    return resultSet;
//}  
//
//	/**
//	 * Returns a NodeSet containing one text node for each token in the first argument.
//   * Delimiters are whitespace.  That is, the delimiters that are used are tab (&#x09),
//   * linefeed (&#x0A), return (&#x0D), and space (&#x20).
//   * Tokens are determined by a call to <code>StringTokenizer</code>.
//   * If the first argument is an empty string or contains only delimiters, the result
//   * will be an empty NodeSet.
//   * Contributed to XalanJ1 by <a href="mailto:benoit.cerrina@writeme.com">Benoit Cerrina</a>.  
//	 * @param myContext an <code>ExpressionContext</code> passed in by the
//   *                  extension mechanism.  This must be an XPathContext.
//	 * @param toTokenize The string to be split into text tokens.
//	 * @return a NodeSet as described above.
//   *
//	 */	
//	public static NodeSet tokenize(ExpressionContext myContext, String toTokenize)
//	{
//    return tokenize(myContext, toTokenize, " \t\n\r");
//  }  

}