public static class PigGenericMapReduce.ReduceWithComparator
This "specialized" reduce class is ONLY to be used in pig queries with
order by a udf. A UDF used for comparison in the order by expects
to be handed tuples. Hence a specialized map class (PigMapReduce.MapWithComparator)
ensures that the "key" used in the order by is wrapped into a tuple (if it
isn't already a tuple). This reduce class unwraps this tuple in the case where
the map had wrapped into a tuple and handes the "unwrapped" key to the POPackage
Nested Class Summary
Nested classes/interfaces inherited from class org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapReduce.Reduce
The reduce function which packages the key and List<Tuple>
into key, Bag<Tuple> after converting Hadoop type key into Pig type.
The package result is either collected as is, if the reduce plan is
empty or after passing through the reduce plan.