@Override
  public byte[] toByteArray() throws IOException {
    FilterProtos.FilterList.Builder builder = FilterProtos.FilterList.newBuilder();
    builder.setOperator(FilterProtos.FilterList.Operator.valueOf(operator.name()));
    ArrayList<Filter> filters = filterListBase.getFilters();
    for (int i = 0, n = filters.size(); i < n; i++) {
      builder.addFilters(ProtobufUtil.toFilter(filters.get(i)));
    }
    return builder.build().toByteArray();
  }
Returns The filter serialized using pb
hbase-client/src/main/java/org/apache/hadoop/hbase/filter/FilterList.java