@Override
  public SystemStreamPartitionGrouper getSystemStreamPartitionGrouper(Config config) {
    if (!(new TaskConfig(config).getBroadcastSystemStreams().isEmpty())) {
      throw new ConfigException("The job configured with AllSspToSingleTaskGrouper cannot have broadcast streams.");
    }

    String processors = config.get(JobConfig.PROCESSOR_LIST);
    List<String> processorList = Arrays.asList(processors.split(","));
    if (processorList.isEmpty()) {
      throw new SamzaException("processor list cannot be empty!");
    }
    return new AllSspToSingleTaskGrouper(processorList);
  }
AllSspToSingleTaskGrouper creates TaskInstances equal to the number of containers and assigns all partitions to be
consumed by each TaskInstance. This is useful, in case of using load-balanced consumers like the high-level Kafka
consumer and Kinesis consumer, where Samza doesn't control the partitions being consumed by the task.

Note that this grouper does not take in broadcast streams yet.
samza-core/src/main/java/org/apache/samza/container/grouper/stream/AllSspToSingleTaskGrouperFactory.java