/** {@inheritDoc} */
  @Override
  public ByteBuffer encode(GridNioSession ses, GridClientMessage msg)
      throws IOException, GridException {
    assert msg != null;

    if (msg instanceof GridTcpRestPacket) return encodeMemcache((GridTcpRestPacket) msg);
    else if (msg == PING_MESSAGE) return ByteBuffer.wrap(PING_PACKET);
    else {
      byte[] data = marshaller.marshal(msg);

      assert data.length > 0;

      ByteBuffer res = ByteBuffer.allocate(data.length + 5);

      res.put(GRIDGAIN_REQ_FLAG);
      res.put(U.intToBytes(data.length));
      res.put(data);

      res.flip();

      return res;
    }
  }
  /**
   * Encodes memcache message to a raw byte array.
   *
   * @param msg Message being serialized.
   * @return Serialized message.
   * @throws GridException If serialization failed.
   */
  private ByteBuffer encodeMemcache(GridTcpRestPacket msg) throws GridException {
    GridByteArrayList res = new GridByteArrayList(HDR_LEN);

    int keyLength = 0;

    int keyFlags = 0;

    if (msg.key() != null) {
      ByteArrayOutputStream rawKey = new ByteArrayOutputStream();

      keyFlags = encodeObj(msg.key(), rawKey);

      msg.key(rawKey.toByteArray());

      keyLength = rawKey.size();
    }

    int dataLength = 0;

    int valFlags = 0;

    if (msg.value() != null) {
      ByteArrayOutputStream rawVal = new ByteArrayOutputStream();

      valFlags = encodeObj(msg.value(), rawVal);

      msg.value(rawVal.toByteArray());

      dataLength = rawVal.size();
    }

    int flagsLength = 0;

    if (msg.addFlags()) // || keyFlags > 0 || valFlags > 0)
    flagsLength = FLAGS_LENGTH;

    res.add(MEMCACHE_RES_FLAG);

    res.add(msg.operationCode());

    // Cast is required due to packet layout.
    res.add((short) keyLength);

    // Cast is required due to packet layout.
    res.add((byte) flagsLength);

    // Data type is always 0x00.
    res.add((byte) 0x00);

    res.add((short) msg.status());

    res.add(keyLength + flagsLength + dataLength);

    res.add(msg.opaque(), 0, msg.opaque().length);

    // CAS, unused.
    res.add(0L);

    assert res.size() == HDR_LEN;

    if (flagsLength > 0) {
      res.add((short) keyFlags);
      res.add((short) valFlags);
    }

    assert msg.key() == null || msg.key() instanceof byte[];
    assert msg.value() == null || msg.value() instanceof byte[];

    if (keyLength > 0) res.add((byte[]) msg.key(), 0, ((byte[]) msg.key()).length);

    if (dataLength > 0) res.add((byte[]) msg.value(), 0, ((byte[]) msg.value()).length);

    return ByteBuffer.wrap(res.entireArray());
  }