docs: protected String nextCNNumeric( char[] chars, int index ) throws IOException 
      {
          //StringBuilder isb = new StringBuilder();
          isb.clear();
          isb.append( chars[ index ]);
          ctrlMask &= ~ISegment.CHECK_CF_MASK;        //reset the fraction check mask.
          
          for ( int j = index + 1; j < chars.length; j++ ) {
              /* 
               * check and deal with '分之' if the 
               * current char is not a Chinese numeric. 
               * (try to recognize a Chinese fraction)
               * 
               * @added 2013-12-14
              */
              if ( NumericUtil.isCNNumeric(chars[j]) == -1 ) {
                  if ( j + 2 < chars.length 
                          && chars[j  ] == '分' 
                          && chars[j+1] == '之'
                          /* check and make sure chars[j+2] is a chinese numeric.
                           * or error will happen on situation like '四六分之' .
                           * @added 2013-12-14 */
                          && NumericUtil.isCNNumeric(chars[j+2]) != -1 ) {
                      isb.append(chars[j++]);
                      isb.append(chars[j++]);
                      isb.append(chars[j  ]);
                      //set the chinese fraction check mask.
                      ctrlMask |= ISegment.CHECK_CF_MASK;
                      continue;
                  } else {
                      break;
                  }
              }
              
              //append the buffer.
              isb.append( chars[j] );
          }
          
          return isb.toString();
      }