Uses of Interface
org.apache.hadoop.mapred.Reducer

Packages that use Reducer

org.apache.hadoop.mapred
org.apache.hadoop.mapred.lib
org.apache.hadoop.mapred.lib.aggregate

Uses of Reducer in org.apache.hadoop.mapred

Methods in org.apache.hadoop.mapred that return types with arguments of type Reducer

Class<? extends Reducer>	JobConf.getCombinerClass() Get the user-defined combiner class used to combine map-outputs before being sent to the reducers.
Class<? extends Reducer>	JobConf.getReducerClass() Get the Reducer class for the job.

Method parameters in org.apache.hadoop.mapred with type arguments of type Reducer

void	JobConf.setCombinerClass(Class<? extends Reducer> theClass) Set the user-defined combiner class used to combine map-outputs before being sent to the reducers.
void	JobConf.setReducerClass(Class<? extends Reducer> theClass) Set the Reducer class for the job.

Uses of Reducer in org.apache.hadoop.mapred.lib

Classes in org.apache.hadoop.mapred.lib that implement Reducer

class	ChainReducer The ChainReducer class allows to chain multiple Mapper classes after a Reducer within the Reducer task.
class	FieldSelectionMapReduce<K,V> This class implements a mapper/reducer class that can be used to perform field selections in a manner similar to unix cut.
class	IdentityReducer<K,V> Performs no reduction, writing all input values directly to the output.
class	LongSumReducer<K> A Reducer that sums long values.

Method parameters in org.apache.hadoop.mapred.lib with type arguments of type Reducer

static <K1,V1,K2,V2> void

ChainReducer.setReducer(JobConf job, Class<? extends Reducer<K1,V1,K2,V2>> klass, Class<? extends K1> inputKeyClass, Class<? extends V1> inputValueClass, Class<? extends K2> outputKeyClass, Class<? extends V2> outputValueClass, boolean byValue, JobConf reducerConf) Sets the Reducer class to the chain job's JobConf.

Uses of Reducer in org.apache.hadoop.mapred.lib.aggregate

Classes in org.apache.hadoop.mapred.lib.aggregate that implement Reducer

class	ValueAggregatorCombiner<K1 extends WritableComparable,V1 extends Writable> This class implements the generic combiner of Aggregate.
class	ValueAggregatorJobBase<K1 extends WritableComparable,V1 extends Writable> This abstract class implements some common functionalities of the the generic mapper, reducer and combiner classes of Aggregate.
class	ValueAggregatorMapper<K1 extends WritableComparable,V1 extends Writable> This class implements the generic mapper of Aggregate.
class	ValueAggregatorReducer<K1 extends WritableComparable,V1 extends Writable> This class implements the generic reducer of Aggregate.