code: public static RaidInfo getFileRaidInfo(final FileStatus stat, 
        Configuration conf, boolean skipHarChecking)
      throws IOException {
      // now look for the parity file
      ParityFilePair ppair = null;
      for (Codec c : Codec.getCodecs()) {
        ppair = ParityFilePair.getParityFile(c, stat, conf, skipHarChecking);
        if (ppair != null) {
          return new RaidInfo(c, ppair, c.parityLength);
        }
      }
      return new RaidInfo(null, ppair, 0);
    }
docs: returns the raid for a given file