Method getClosestRowBefore

src/RegionClient.java:731–799

Finds the highest row that's less than or equal to the given row. @param region The region in which to search. @param tabl The table to which the key belongs. @param row The row to search. @param family The family to get. @return A Deferred ArrayList of KeyValue. The list is guarant

(final RegionInfo region,
                                                      final byte[] tabl,
                                                      final byte[] row,
                                                      final byte[] family)

   * guaranteed to be non-{@code null} but may be empty.
   */
  public
    Deferred<ArrayList<KeyValue>> getClosestRowBefore(final RegionInfo region,
                                                      final byte[] tabl,
                                                      final byte[] row,
                                                      final byte[] family) {
    final class GetClosestRowBefore extends HBaseRpc {
      GetClosestRowBefore() {
        super(tabl, row);
      }

      @Override
      byte[] method(final byte server_version) {
        return server_version >= SERVER_VERSION_095_OR_ABOVE
          ? GetRequest.GGET : GET_CLOSEST_ROW_BEFORE;
      }

      @Override
      Object deserialize(final ChannelBuffer buf, final int cell_size) {
        assert cell_size == 0 : "cell_size=" + cell_size;
        final ClientPB.GetResponse resp =
          readProtobuf(buf, ClientPB.GetResponse.PARSER);
        return GetRequest.extractResponse(resp, buf, cell_size);
      }

      @Override
      ChannelBuffer serialize(final byte server_version) {
        if (server_version < SERVER_VERSION_095_OR_ABOVE) {
          return serializeOld(server_version);
        }
        final ClientPB.Get getpb = ClientPB.Get.newBuilder()
          .setRow(Bytes.wrap(row))
          .addColumn(FAM_INFO)  // Fetch from one family only.
          .setClosestRowBefore(true)
          .build();
        final ClientPB.GetRequest get = ClientPB.GetRequest.newBuilder()
          .setRegion(region.toProtobuf())
          .setGet(getpb)
          .build();
        return toChannelBuffer(GetRequest.GGET, get);
      }

      private ChannelBuffer serializeOld(final byte server_version) {
        // region.length and row.length will use at most a 3-byte VLong.
        // This is because VLong wastes 1 byte of meta-data + 2 bytes of
        // payload.  HBase's own KeyValue code uses a short to store the row
        // length.  Finally, family.length cannot be on more than 1 byte,
        // HBase's own KeyValue code uses a byte to store the family length.
        final byte[] region_name = region.name();
        final ChannelBuffer buf = newBuffer(server_version,
          + 4                                      // num param
          + 1 + 2 + region_name.length             // 3 times 1 byte for the
          + 1 + 4 + row.length                     //   parm type + VLong
          + 1 + 1 + family.length);                //             + array
        buf.writeInt(3);  // Number of parameters.
        writeHBaseByteArray(buf, region_name);     // 1st param.
        writeHBaseByteArray(buf, row);             // 2nd param.
        writeHBaseByteArray(buf, family);          // 3rd param.
        return buf;