private Set<Integer> getPartitions(SystemStream systemStream) {
      String streamName = systemStream.getStream();

      if (!streamPartitionsMap.containsKey(streamName)) {
        String partitions = config.get(String.format(CONFIG_STREAM_PARTITIONS, streamName));
        streamPartitionsMap.put(streamName, Arrays.stream(partitions.split(CFG_PARTITIONS_DELIMITER))
            .map(Integer::parseInt)
            .collect(Collectors.toSet()));
      }
      return streamPartitionsMap.get(streamName);
    }
Comma separated list of partitions that needs to be assigned to this task.
samza-tools/src/main/java/org/apache/samza/tools/benchmark/ConfigBasedSspGrouperFactory.java