/**
   * Constructor for MetadataResponse where there are errors for some of the topics, error data take
   * precedence over cluster information for particular topic
   */
  public MetadataResponse(Cluster cluster, Map<String, Errors> errors) {
    super(new Struct(CURRENT_SCHEMA));

    List<Struct> brokerArray = new ArrayList<Struct>();
    for (Node node : cluster.nodes()) {
      Struct broker = struct.instance(BROKERS_KEY_NAME);
      broker.set(NODE_ID_KEY_NAME, node.id());
      broker.set(HOST_KEY_NAME, node.host());
      broker.set(PORT_KEY_NAME, node.port());
      brokerArray.add(broker);
    }
    struct.set(BROKERS_KEY_NAME, brokerArray.toArray());

    List<Struct> topicArray = new ArrayList<Struct>();
    for (Map.Entry<String, Errors> errorEntry : errors.entrySet()) {
      Struct topicData = struct.instance(TOPIC_METATDATA_KEY_NAME);
      topicData.set(TOPIC_KEY_NAME, errorEntry.getKey());
      topicData.set(TOPIC_ERROR_CODE_KEY_NAME, errorEntry.getValue().code());
      topicData.set(PARTITION_METADATA_KEY_NAME, new Struct[0]);
      topicArray.add(topicData);
    }

    for (String topic : cluster.topics()) {
      if (!errors.containsKey(topic)) {
        Struct topicData = struct.instance(TOPIC_METATDATA_KEY_NAME);
        topicData.set(TOPIC_KEY_NAME, topic);
        topicData.set(TOPIC_ERROR_CODE_KEY_NAME, Errors.NONE.code());
        List<Struct> partitionArray = new ArrayList<Struct>();
        for (PartitionInfo fetchPartitionData : cluster.partitionsForTopic(topic)) {
          Struct partitionData = topicData.instance(PARTITION_METADATA_KEY_NAME);
          partitionData.set(PARTITION_ERROR_CODE_KEY_NAME, Errors.NONE.code());
          partitionData.set(PARTITION_KEY_NAME, fetchPartitionData.partition());
          partitionData.set(LEADER_KEY_NAME, fetchPartitionData.leader().id());
          ArrayList<Integer> replicas = new ArrayList<Integer>();
          for (Node node : fetchPartitionData.replicas()) replicas.add(node.id());
          partitionData.set(REPLICAS_KEY_NAME, replicas.toArray());
          ArrayList<Integer> isr = new ArrayList<Integer>();
          for (Node node : fetchPartitionData.inSyncReplicas()) isr.add(node.id());
          partitionData.set(ISR_KEY_NAME, isr.toArray());
          partitionArray.add(partitionData);
        }
        topicData.set(PARTITION_METADATA_KEY_NAME, partitionArray.toArray());
        topicArray.add(topicData);
      }
    }
    struct.set(TOPIC_METATDATA_KEY_NAME, topicArray.toArray());

    this.cluster = cluster;
    this.errors = errors;
  }
  public MetadataResponse(Struct struct) {
    super(struct);
    Map<String, Errors> errors = new HashMap<String, Errors>();
    Map<Integer, Node> brokers = new HashMap<Integer, Node>();
    Object[] brokerStructs = (Object[]) struct.get(BROKERS_KEY_NAME);
    for (int i = 0; i < brokerStructs.length; i++) {
      Struct broker = (Struct) brokerStructs[i];
      int nodeId = broker.getInt(NODE_ID_KEY_NAME);
      String host = broker.getString(HOST_KEY_NAME);
      int port = broker.getInt(PORT_KEY_NAME);
      brokers.put(nodeId, new Node(nodeId, host, port));
    }
    List<PartitionInfo> partitions = new ArrayList<PartitionInfo>();
    Object[] topicInfos = (Object[]) struct.get(TOPIC_METATDATA_KEY_NAME);
    for (int i = 0; i < topicInfos.length; i++) {
      Struct topicInfo = (Struct) topicInfos[i];
      short topicError = topicInfo.getShort(TOPIC_ERROR_CODE_KEY_NAME);
      String topic = topicInfo.getString(TOPIC_KEY_NAME);
      if (topicError == Errors.NONE.code()) {
        Object[] partitionInfos = (Object[]) topicInfo.get(PARTITION_METADATA_KEY_NAME);
        for (int j = 0; j < partitionInfos.length; j++) {
          Struct partitionInfo = (Struct) partitionInfos[j];
          int partition = partitionInfo.getInt(PARTITION_KEY_NAME);
          int leader = partitionInfo.getInt(LEADER_KEY_NAME);
          Node leaderNode = leader == -1 ? null : brokers.get(leader);
          Object[] replicas = (Object[]) partitionInfo.get(REPLICAS_KEY_NAME);
          Node[] replicaNodes = new Node[replicas.length];
          for (int k = 0; k < replicas.length; k++) replicaNodes[k] = brokers.get(replicas[k]);
          Object[] isr = (Object[]) partitionInfo.get(ISR_KEY_NAME);
          Node[] isrNodes = new Node[isr.length];
          for (int k = 0; k < isr.length; k++) isrNodes[k] = brokers.get(isr[k]);
          partitions.add(new PartitionInfo(topic, partition, leaderNode, replicaNodes, isrNodes));
        }
      } else {
        errors.put(topic, Errors.forCode(topicError));
      }
    }

    this.errors = errors;
    this.cluster = new Cluster(brokers.values(), partitions, unauthorizedTopics(errors));
  }