org.apache.crunch
Class CombineFn.AggregatorCombineFn<K,V>
java.lang.Object
org.apache.crunch.DoFn<Pair<S,Iterable<T>>,Pair<S,T>>
org.apache.crunch.CombineFn<K,V>
org.apache.crunch.CombineFn.AggregatorCombineFn<K,V>
- All Implemented Interfaces:
- Serializable
- Enclosing class:
- CombineFn<S,T>
public static class CombineFn.AggregatorCombineFn<K,V>
- extends CombineFn<K,V>
A CombineFn
that delegates all of the actual work to an
Aggregator
instance.
- See Also:
- Serialized Form
Nested classes/interfaces inherited from class org.apache.crunch.CombineFn |
CombineFn.Aggregator<T>, CombineFn.AggregatorCombineFn<K,V>, CombineFn.AggregatorFactory<T>, CombineFn.FirstNAggregator<V>, CombineFn.LastNAggregator<V>, CombineFn.MaxBigInts, CombineFn.MaxDoubles, CombineFn.MaxFloats, CombineFn.MaxInts, CombineFn.MaxLongs, CombineFn.MaxNAggregator<V extends Comparable<V>>, CombineFn.MinBigInts, CombineFn.MinDoubles, CombineFn.MinFloats, CombineFn.MinInts, CombineFn.MinLongs, CombineFn.MinNAggregator<V extends Comparable<V>>, CombineFn.PairAggregator<V1,V2>, CombineFn.QuadAggregator<A,B,C,D>, CombineFn.StringConcatAggregator, CombineFn.SumBigInts, CombineFn.SumDoubles, CombineFn.SumFloats, CombineFn.SumInts, CombineFn.SumLongs, CombineFn.TripAggregator<A,B,C>, CombineFn.TupleNAggregator |
Fields inherited from class org.apache.crunch.CombineFn |
MAX_BIGINTS, MAX_DOUBLES, MAX_FLOATS, MAX_INTS, MAX_LONGS, MIN_BIGINTS, MIN_DOUBLES, MIN_FLOATS, MIN_INTS, MIN_LONGS, SUM_BIGINTS, SUM_DOUBLES, SUM_FLOATS, SUM_INTS, SUM_LONGS |
Methods inherited from class org.apache.crunch.CombineFn |
aggregator, aggregatorFactory, FIRST_N, LAST_N, MAX_BIGINTS, MAX_BIGINTS, MAX_DOUBLES, MAX_DOUBLES, MAX_FLOATS, MAX_FLOATS, MAX_INTS, MAX_INTS, MAX_LONGS, MAX_LONGS, MIN_BIGINTS, MIN_BIGINTS, MIN_DOUBLES, MIN_DOUBLES, MIN_FLOATS, MIN_FLOATS, MIN_INTS, MIN_INTS, MIN_LONGS, MIN_LONGS, pairAggregator, quadAggregator, STRING_CONCAT, STRING_CONCAT, SUM_BIGINTS, SUM_DOUBLES, SUM_FLOATS, SUM_INTS, SUM_LONGS, tripAggregator, tupleAggregator |
CombineFn.AggregatorCombineFn
public CombineFn.AggregatorCombineFn(CombineFn.Aggregator<V> aggregator)
process
public void process(Pair<K,Iterable<V>> input,
Emitter<Pair<K,V>> emitter)
- Description copied from class:
DoFn
- Processes the records from a
PCollection
.
Note: Crunch can reuse a single input record object whose content
changes on each DoFn.process(Object, Emitter)
method call. This
functionality is imposed by Hadoop's Reducer implementation: The framework will reuse the key and value
objects that are passed into the reduce, therefore the application should
clone the objects they want to keep a copy of.
- Specified by:
process
in class DoFn<Pair<K,Iterable<V>>,Pair<K,V>>
- Parameters:
input
- The input record.emitter
- The emitter to send the output to
Copyright © 2012 The Apache Software Foundation. All Rights Reserved.