code: static void parseSkeleton(String skeleton, int[] skeletonFieldWidth) {
          int PATTERN_CHAR_BASE = 0x41;
          for ( int i = 0; i < skeleton.length(); ++i ) {
              ++skeletonFieldWidth[skeleton.charAt(i) - PATTERN_CHAR_BASE];
          }
      }
docs: Parse skeleton, save each field's width.
  It is used for looking for best match skeleton,
  and adjust pattern field width.
  @param skeleton            skeleton to be parsed
  @param skeletonFieldWidth  parsed skeleton field width