private SystemStreamPartitionGrouper getSystemStreamPartitionGrouper() {
    JobConfig jobConfig = new JobConfig(config);
    String factoryString = jobConfig.getSystemStreamPartitionGrouperFactory();
    SystemStreamPartitionGrouper grouper =
        ReflectionUtil.getObj(factoryString, SystemStreamPartitionGrouperFactory.class)
            .getSystemStreamPartitionGrouper(jobConfig);
    return grouper;
  }
Gets a SystemStreamPartitionGrouper object from the configuration.
samza-azure/src/main/java/org/apache/samza/coordinator/AzureJobCoordinator.java