Uses of Interface
org.apache.hadoop.mapred.Reducer
Packages that use Reducer
Package
Description
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Uses of Reducer in org.apache.hadoop.mapred
Methods in org.apache.hadoop.mapred that return types with arguments of type ReducerModifier and TypeMethodDescriptionJobConf.getCombinerClass()Get the user-defined combiner class used to combine map-outputs before being sent to the reducers.JobConf.getReducerClass()Get theReducerclass for the job.Method parameters in org.apache.hadoop.mapred with type arguments of type ReducerModifier and TypeMethodDescriptionvoidJobConf.setCombinerClass(Class<? extends Reducer> theClass) Set the user-defined combiner class used to combine map-outputs before being sent to the reducers.voidJobConf.setReducerClass(Class<? extends Reducer> theClass) Set theReducerclass for the job. -
Uses of Reducer in org.apache.hadoop.mapred.lib
Classes in org.apache.hadoop.mapred.lib that implement ReducerModifier and TypeClassDescriptionclassThe ChainReducer class allows to chain multiple Mapper classes after a Reducer within the Reducer task.classThis class implements a mapper/reducer class that can be used to perform field selections in a manner similar to unix cut.classIdentityReducer<K,V> Performs no reduction, writing all input values directly to the output.classAReducerthat sums long values.Method parameters in org.apache.hadoop.mapred.lib with type arguments of type ReducerModifier and TypeMethodDescriptionstatic <K1,V1, K2, V2>
voidChainReducer.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 ReducerModifier and TypeClassDescriptionclassValueAggregatorCombiner<K1 extends WritableComparable,V1 extends Writable> This class implements the generic combiner of Aggregate.classValueAggregatorJobBase<K1 extends WritableComparable,V1 extends Writable> This abstract class implements some common functionalities of the the generic mapper, reducer and combiner classes of Aggregate.classValueAggregatorMapper<K1 extends WritableComparable,V1 extends Writable> This class implements the generic mapper of Aggregate.classValueAggregatorReducer<K1 extends WritableComparable,V1 extends Writable> This class implements the generic reducer of Aggregate.