code: synchronized public boolean selectInputStreams(
        Collection<EditLogInputStream> streams, long fromTxId,
        boolean inProgressOk, boolean validateInProgressSegments,
        int minRedundancy) throws IOException {
      final PriorityQueue<EditLogInputStream> allStreams = 
          new PriorityQueue<EditLogInputStream>(64,
              EDIT_LOG_INPUT_STREAM_COMPARATOR);
      for (JournalAndStream jas : journals) {
        if (jas.isDisabled()) {
          LOG.info("Skipping jas " + jas + " since it's disabled");
          continue;
        }
        try {
          jas.getManager().selectInputStreams(allStreams, fromTxId, inProgressOk,
              validateInProgressSegments);
        } catch (IOException ioe) {
          LOG.warn("Unable to determine input streams from " + jas.getManager()
              + ". Skipping.", ioe);
        }
      }
      return chainAndMakeRedundantStreams(streams, allStreams, fromTxId,
          inProgressOk, minRedundancy);
    }
docs: Selects input streams. Returns true if each stream meets min redundancy,
  false otherwise.