code: private void whitespaceChars(int low, int hi) {
          if (low < 0)
              low = 0;
          if (hi >= ctype.length)
              hi = ctype.length - 1;
          while (low <= hi)
              ctype[low++] = CT_WHITESPACE;
      }
docs: Specifies that all characters <i>c</i> in the range
  <code>low&nbsp;&lt;=&nbsp;<i>c</i>&nbsp;&lt;=&nbsp;high</code>
  are white space characters. White space characters serve only to
  separate tokens in the input stream.
  
  <p>Any other attribute settings for the characters in the specified
  range are cleared.
  
  @param   low   the low end of the range.
  @param   hi    the high end of the range.