@Override
    protected boolean includeRegionInSplit(final byte[] startKey, final byte[] endKey) {
      if (
        Bytes.compareTo(startKey, prefixEndKey) < 0 && (Bytes.compareTo(prefixStartKey, endKey) < 0
          || Bytes.equals(endKey, HConstants.EMPTY_END_ROW))
      ) {
        return false;
      } else {
        return true;
      }
    }
Exclude regions which contain rows starting with "b".
hbase-mapreduce/src/test/java/org/apache/hadoop/hbase/mapreduce/TestTableInputFormatBase.java