code: public static boolean raidedByOtherHighPriCodec(Configuration conf,
          FileStatus stat, Codec codec) throws IOException {
      
      for (Codec tcodec : Codec.getCodecs()) {
        if (tcodec.priority > codec.priority) {
          if (stat.isDir() && !tcodec.isDirRaid) {
            // A directory could not be raided by a file level codec.
            continue;
          }
          
          // check if high priority parity file exists.
          if (ParityFilePair.parityExists(stat, tcodec, conf)) {
            InjectionHandler.processEvent(InjectionEvent.RAID_ENCODING_SKIP_PATH);
            return true;
          }
        }
      }
      
      return false;
    }
docs: check if the file is already raided by high priority codec