@Override
  public boolean containsRow(byte[] row) {
    CellComparator cellComparator = CellComparatorImpl.getCellComparator(tableName);
    return cellComparator.compareRows(row, startKey) >= 0
      && (cellComparator.compareRows(row, endKey) < 0
        || Bytes.equals(endKey, HConstants.EMPTY_BYTE_ARRAY));
  }
Return true if the given row falls in this region.
hbase-client/src/main/java/org/apache/hadoop/hbase/client/MutableRegionInfo.java