SystemStreamPartitionGrouper (samza-api 1.9.0-SNAPSHOT API)

```
public interface SystemStreamPartitionGrouper
```
Group a set of SystemStreamPartitions into logical taskNames that share a common characteristic, defined by the implementation. Each taskName has a key that uniquely describes what sets may be in it, but does not generally enumerate the elements of those sets. For example, a SystemStreamPartitionGrouper that groups SystemStreamPartitions (each with 4 partitions) by their partition, would end up generating four TaskNames: 0, 1, 2, 3. These TaskNames describe the partitions but do not list all of the SystemStreamPartitions, which allows new SystemStreamPartitions to be added later without changing the definition of the TaskNames, assuming these new SystemStreamPartitions do not have more than four partitions. On the other hand, a SystemStreamPartitionGrouper that wanted each SystemStreamPartition to be its own, unique group would use the SystemStreamPartition's entire description to generate the TaskNames.

All Methods Instance Methods Abstract Methods
Modifier and Type	Method and Description
`java.util.Map<TaskName,java.util.Set<SystemStreamPartition>>`	`group(java.util.Set<SystemStreamPartition> systemStreamPartitions)` Groups the input systemStreamPartitions into the logical taskNames.

Interface SystemStreamPartitionGrouper