code: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements. See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership. The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the  "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  /*
   * $Id$
   */
  package org.apache.xalan.lib;
  
  import org.apache.xml.dtm.ref.DTMNodeProxy;
  
  import org.w3c.dom.Node;
  import org.w3c.dom.NodeList;
  
  /**
   * 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;
    }
  }
  