/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/*

 * Copyright 1999-2004 The Apache Software Foundation.

 *

 * Licensed 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: ExsltBase.java,v 1.1.2.1 2005/08/01 02:08:51 jeffsuttor Exp $

 */

package com.sun.org.apache.xalan.internal.lib;

import com.sun.org.apache.xml.internal.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;

  }

}