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.xml.utils;
  
  /**
   * Class used to verify whether the specified <var>ch</var> 
   * conforms to the XML 1.0 definition of whitespace. 
   * @xsl.usage internal
   */
  public class XMLCharacterRecognizer
  {
  
    /**
     * Returns whether the specified <var>ch</var> conforms to the XML 1.0 definition
     * of whitespace.  Refer to <A href="http://www.w3.org/TR/1998/REC-xml-19980210#NT-S">
     * the definition of <CODE>S</CODE></A> for details.
     * @param ch Character to check as XML whitespace.
     * @return =true if <var>ch</var> is XML whitespace; otherwise =false.
     */
    public static boolean isWhiteSpace(char ch)
    {
      return (ch == 0x20) || (ch == 0x09) || (ch == 0xD) || (ch == 0xA);
    }
  
    /**
     * Tell if the string is whitespace.
     *
     * @param ch Character array to check as XML whitespace.
     * @param start Start index of characters in the array
     * @param length Number of characters in the array 
     * @return True if the characters in the array are 
     * XML whitespace; otherwise, false.
     */
    public static boolean isWhiteSpace(char ch[], int start, int length)
    {
  
      int end = start + length;
  
      for (int s = start; s < end; s++)
      {
        if (!isWhiteSpace(ch[s]))
          return false;
      }
  
      return true;
    }
  
    /**
     * Tell if the string is whitespace.
     *
     * @param buf StringBuffer to check as XML whitespace.
     * @return True if characters in buffer are XML whitespace, false otherwise
     */
    public static boolean isWhiteSpace(StringBuffer buf)
    {
  
      int n = buf.length();
  
      for (int i = 0; i < n; i++)
      {
        if (!isWhiteSpace(buf.charAt(i)))
          return false;
      }
  
      return true;
    }
    
    /**
     * Tell if the string is whitespace.
     *
     * @param s String to check as XML whitespace.
     * @return True if characters in buffer are XML whitespace, false otherwise
     */
    public static boolean isWhiteSpace(String s)
    {
  
      if(null != s)
      {
        int n = s.length();
    
        for (int i = 0; i < n; i++)
        {
          if (!isWhiteSpace(s.charAt(i)))
            return false;
        }
      }
  
      return true;
    }
  
  }
  