| Interface | Description | 
|---|---|
| SystemStreamPartitionGrouper | Group a set of SystemStreamPartitions into logical taskNames that share a common characteristic, defined
 by the implementation. | 
| SystemStreamPartitionGrouperFactory | Return an instance a SystemStreamPartitionGrouper per the particular implementation | 
| SystemStreamPartitionMapper | Input streams of a samza job can be either expanded or contracted by the user. | 
| SystemStreamPartitionMapperFactory |