How to use

org.apache.kafka.common.requests.JoinGroupRequest$ProtocolMetadata

constructor

@Override
public List<ProtocolMetadata> metadata() {
  this.joinedSubscription = subscriptions.subscription();
  List<ProtocolMetadata> metadataList = new ArrayList<>();
  for (PartitionAssignor assignor : assignors) {
    Subscription subscription = assignor.subscription(joinedSubscription);
    ByteBuffer metadata = ConsumerProtocol.serializeSubscription(subscription);
    metadataList.add(new ProtocolMetadata(assignor.name(), metadata));
  }
  return metadataList;
}

@Override
protected List<JoinGroupRequest.ProtocolMetadata> metadata() {
  return Collections.singletonList(new JoinGroupRequest.ProtocolMetadata("dummy-subprotocol", EMPTY_DATA));
}

private JoinGroupRequest createJoinGroupRequest(int version) {
  ByteBuffer metadata = ByteBuffer.wrap(new byte[] {});
  List<JoinGroupRequest.ProtocolMetadata> protocols = new ArrayList<>();
  protocols.add(new JoinGroupRequest.ProtocolMetadata("consumer-range", metadata));
  if (version == 0) {
    return new JoinGroupRequest.Builder("group1", 30000, "consumer1", "consumer", protocols).
        build((short) version);
  } else {
    return new JoinGroupRequest.Builder("group1", 10000, "consumer1", "consumer", protocols).
        setRebalanceTimeout(60000).build();
  }
}

@Override
public List<ProtocolMetadata> metadata() {
  configSnapshot = configStorage.snapshot();
  ConnectProtocol.WorkerState workerState = new ConnectProtocol.WorkerState(restUrl, configSnapshot.offset());
  ByteBuffer metadata = ConnectProtocol.serializeMetadata(workerState);
  return Collections.singletonList(new ProtocolMetadata(DEFAULT_SUBPROTOCOL, metadata));
}

@Override
public List<ProtocolMetadata> metadata() {
  configSnapshot = taskConfigManager.snapshot();
  DatalinkProtocol.WorkerState workerState = new DatalinkProtocol.WorkerState(restUrl, configSnapshot.version());
  ByteBuffer metadata = DatalinkProtocol.serializeMetadata(workerState);
  return Collections.singletonList(new ProtocolMetadata(DEFAULT_SUBPROTOCOL, metadata));
}

public JoinGroupRequest(Struct struct, short versionId) {
  super(ApiKeys.JOIN_GROUP, versionId);
  groupId = struct.get(GROUP_ID);
  sessionTimeout = struct.getInt(SESSION_TIMEOUT_KEY_NAME);
  if (struct.hasField(REBALANCE_TIMEOUT_KEY_NAME))
    // rebalance timeout is added in v1
    rebalanceTimeout = struct.getInt(REBALANCE_TIMEOUT_KEY_NAME);
  else
    // v0 had no rebalance timeout but used session timeout implicitly
    rebalanceTimeout = sessionTimeout;
  memberId = struct.get(MEMBER_ID);
  protocolType = struct.getString(PROTOCOL_TYPE_KEY_NAME);
  groupProtocols = new ArrayList<>();
  for (Object groupProtocolObj : struct.getArray(GROUP_PROTOCOLS_KEY_NAME)) {
    Struct groupProtocolStruct = (Struct) groupProtocolObj;
    String name = groupProtocolStruct.getString(PROTOCOL_NAME_KEY_NAME);
    ByteBuffer metadata = groupProtocolStruct.getBytes(PROTOCOL_METADATA_KEY_NAME);
    groupProtocols.add(new ProtocolMetadata(name, metadata));
  }
}