How to use

writeHeader

method

in

org.apache.flink.queryablestate.network.messages.MessageSerializer

/**
 * Serializes the failure message sent to the
 * {@link org.apache.flink.queryablestate.network.Client} in case of
 * server related errors.
 *
 * @param alloc            The {@link ByteBufAllocator} used to allocate the buffer to serialize the message into.
 * @param cause            The exception thrown at the server.
 * @return        The failure message.
 */
public static ByteBuf serializeServerFailure(
    final ByteBufAllocator alloc,
    final Throwable cause) throws IOException {
  final ByteBuf buf = alloc.ioBuffer();
  // Frame length is set at end
  buf.writeInt(0);
  writeHeader(buf, MessageType.SERVER_FAILURE);
  try (ByteBufOutputStream bbos = new ByteBufOutputStream(buf);
      ObjectOutput out = new ObjectOutputStream(bbos)) {
    out.writeObject(cause);
  }
  // Set frame length
  int frameLength = buf.readableBytes() - Integer.BYTES;
  buf.setInt(0, frameLength);
  return buf;
}

/**
 * Helper for serializing the messages.
 *
 * @param alloc            The {@link ByteBufAllocator} used to allocate the buffer to serialize the message into.
 * @param requestId        The id of the request to which the message refers to.
 * @param messageType    The {@link MessageType type of the message}.
 * @param payload        The serialized version of the message.
 * @return A {@link ByteBuf} containing the serialized message.
 */
private static ByteBuf writePayload(
    final ByteBufAllocator alloc,
    final long requestId,
    final MessageType messageType,
    final byte[] payload) {
  final int frameLength = HEADER_LENGTH + REQUEST_ID_SIZE + payload.length;
  final ByteBuf buf = alloc.ioBuffer(frameLength + Integer.BYTES);
  buf.writeInt(frameLength);
  writeHeader(buf, messageType);
  buf.writeLong(requestId);
  buf.writeBytes(payload);
  return buf;
}

/**
 * Serializes the exception containing the failure message sent to the
 * {@link org.apache.flink.queryablestate.network.Client} in case of
 * protocol related errors.
 *
 * @param alloc            The {@link ByteBufAllocator} used to allocate the buffer to serialize the message into.
 * @param requestId        The id of the request to which the message refers to.
 * @param cause            The exception thrown at the server.
 * @return A {@link ByteBuf} containing the serialized message.
 */
public static ByteBuf serializeRequestFailure(
    final ByteBufAllocator alloc,
    final long requestId,
    final Throwable cause) throws IOException {
  final ByteBuf buf = alloc.ioBuffer();
  // Frame length is set at the end
  buf.writeInt(0);
  writeHeader(buf, MessageType.REQUEST_FAILURE);
  buf.writeLong(requestId);
  try (ByteBufOutputStream bbos = new ByteBufOutputStream(buf);
      ObjectOutput out = new ObjectOutputStream(bbos)) {
    out.writeObject(cause);
  }
  // Set frame length
  int frameLength = buf.readableBytes() - Integer.BYTES;
  buf.setInt(0, frameLength);
  return buf;
}

/**
 * Serializes the failure message sent to the
 * {@link org.apache.flink.queryablestate.network.Client} in case of
 * server related errors.
 *
 * @param alloc            The {@link ByteBufAllocator} used to allocate the buffer to serialize the message into.
 * @param cause            The exception thrown at the server.
 * @return        The failure message.
 */
public static ByteBuf serializeServerFailure(
    final ByteBufAllocator alloc,
    final Throwable cause) throws IOException {
  final ByteBuf buf = alloc.ioBuffer();
  // Frame length is set at end
  buf.writeInt(0);
  writeHeader(buf, MessageType.SERVER_FAILURE);
  try (ByteBufOutputStream bbos = new ByteBufOutputStream(buf);
      ObjectOutput out = new ObjectOutputStream(bbos)) {
    out.writeObject(cause);
  }
  // Set frame length
  int frameLength = buf.readableBytes() - Integer.BYTES;
  buf.setInt(0, frameLength);
  return buf;
}

/**
 * Serializes the failure message sent to the
 * {@link org.apache.flink.queryablestate.network.Client} in case of
 * server related errors.
 *
 * @param alloc            The {@link ByteBufAllocator} used to allocate the buffer to serialize the message into.
 * @param cause            The exception thrown at the server.
 * @return        The failure message.
 */
public static ByteBuf serializeServerFailure(
    final ByteBufAllocator alloc,
    final Throwable cause) throws IOException {
  final ByteBuf buf = alloc.ioBuffer();
  // Frame length is set at end
  buf.writeInt(0);
  writeHeader(buf, MessageType.SERVER_FAILURE);
  try (ByteBufOutputStream bbos = new ByteBufOutputStream(buf);
      ObjectOutput out = new ObjectOutputStream(bbos)) {
    out.writeObject(cause);
  }
  // Set frame length
  int frameLength = buf.readableBytes() - Integer.BYTES;
  buf.setInt(0, frameLength);
  return buf;
}

/**
 * Serializes the exception containing the failure message sent to the
 * {@link org.apache.flink.queryablestate.network.Client} in case of
 * protocol related errors.
 *
 * @param alloc            The {@link ByteBufAllocator} used to allocate the buffer to serialize the message into.
 * @param requestId        The id of the request to which the message refers to.
 * @param cause            The exception thrown at the server.
 * @return A {@link ByteBuf} containing the serialized message.
 */
public static ByteBuf serializeRequestFailure(
    final ByteBufAllocator alloc,
    final long requestId,
    final Throwable cause) throws IOException {
  final ByteBuf buf = alloc.ioBuffer();
  // Frame length is set at the end
  buf.writeInt(0);
  writeHeader(buf, MessageType.REQUEST_FAILURE);
  buf.writeLong(requestId);
  try (ByteBufOutputStream bbos = new ByteBufOutputStream(buf);
      ObjectOutput out = new ObjectOutputStream(bbos)) {
    out.writeObject(cause);
  }
  // Set frame length
  int frameLength = buf.readableBytes() - Integer.BYTES;
  buf.setInt(0, frameLength);
  return buf;
}

/**
 * Helper for serializing the messages.
 *
 * @param alloc            The {@link ByteBufAllocator} used to allocate the buffer to serialize the message into.
 * @param requestId        The id of the request to which the message refers to.
 * @param messageType    The {@link MessageType type of the message}.
 * @param payload        The serialized version of the message.
 * @return A {@link ByteBuf} containing the serialized message.
 */
private static ByteBuf writePayload(
    final ByteBufAllocator alloc,
    final long requestId,
    final MessageType messageType,
    final byte[] payload) {
  final int frameLength = HEADER_LENGTH + REQUEST_ID_SIZE + payload.length;
  final ByteBuf buf = alloc.ioBuffer(frameLength + Integer.BYTES);
  buf.writeInt(frameLength);
  writeHeader(buf, messageType);
  buf.writeLong(requestId);
  buf.writeBytes(payload);
  return buf;
}

/**
 * Serializes the exception containing the failure message sent to the
 * {@link org.apache.flink.queryablestate.network.Client} in case of
 * protocol related errors.
 *
 * @param alloc            The {@link ByteBufAllocator} used to allocate the buffer to serialize the message into.
 * @param requestId        The id of the request to which the message refers to.
 * @param cause            The exception thrown at the server.
 * @return A {@link ByteBuf} containing the serialized message.
 */
public static ByteBuf serializeRequestFailure(
    final ByteBufAllocator alloc,
    final long requestId,
    final Throwable cause) throws IOException {
  final ByteBuf buf = alloc.ioBuffer();
  // Frame length is set at the end
  buf.writeInt(0);
  writeHeader(buf, MessageType.REQUEST_FAILURE);
  buf.writeLong(requestId);
  try (ByteBufOutputStream bbos = new ByteBufOutputStream(buf);
      ObjectOutput out = new ObjectOutputStream(bbos)) {
    out.writeObject(cause);
  }
  // Set frame length
  int frameLength = buf.readableBytes() - Integer.BYTES;
  buf.setInt(0, frameLength);
  return buf;
}

/**
 * Helper for serializing the messages.
 *
 * @param alloc            The {@link ByteBufAllocator} used to allocate the buffer to serialize the message into.
 * @param requestId        The id of the request to which the message refers to.
 * @param messageType    The {@link MessageType type of the message}.
 * @param payload        The serialized version of the message.
 * @return A {@link ByteBuf} containing the serialized message.
 */
private static ByteBuf writePayload(
    final ByteBufAllocator alloc,
    final long requestId,
    final MessageType messageType,
    final byte[] payload) {
  final int frameLength = HEADER_LENGTH + REQUEST_ID_SIZE + payload.length;
  final ByteBuf buf = alloc.ioBuffer(frameLength + Integer.BYTES);
  buf.writeInt(frameLength);
  writeHeader(buf, messageType);
  buf.writeLong(requestId);
  buf.writeBytes(payload);
  return buf;
}