code: public int getNumPartitions(String topicName) {
          List<PartitionInfo> partitionList = getPartitionInfo(topicName);
          return partitionList != null ? partitionList.size() : 0;
      }
docs: Gets number of partitions of a topic.
  
  @param topicName
  @return topic's number of partitions, or {@code 0} if the topic does not
  exist
  @since 1.2.0