/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 1999 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.NodeList;
import org.apache.xml.dtm.ref.DTMNodeProxy;

/**
 * The base class for some EXSLT extension classes.
 * It contains common utility methods to be used by the sub-classes.
 */
public abstract class ExsltBase
{
  /**
   * Return the string value of a Node
   *
   * @param n The Node.
   * @return The string value of the Node
   */
  protected static String toString(Node n)
  {
    if (n instanceof DTMNodeProxy)
  	 return ((DTMNodeProxy)n).getStringValue();
    else
    {
      String value = n.getNodeValue();
      if (value == null)
      {
        NodeList nodelist = n.getChildNodes();
        StringBuffer buf = new StringBuffer();
        for (int i = 0; i < nodelist.getLength(); i++)
        {
          Node childNode = nodelist.item(i);
          buf.append(toString(childNode));
        }
        return buf.toString();
      }
      else
        return value;
    }
  }
  
  /**
   * Convert the string value of a Node to a number.
   * Return NaN if the string is not a valid number.
   *
   * @param n The Node.
   * @return The number value of the Node
   */
  protected static double toNumber(Node n)
  {
    double d = 0.0;
    String str = toString(n);
    try
    {
      d = Double.valueOf(str).doubleValue();
    }
    catch (NumberFormatException e)
    {
      d= Double.NaN;  		
    }
    return d;
  }
}