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org.apache.gora.mapreduce
Class GoraReducer<K1,V1,K2,V2 extends Persistent>

java.lang.Object
  org.apache.hadoop.mapreduce.Reducer<K1,V1,K2,V2>
      org.apache.gora.mapreduce.GoraReducer<K1,V1,K2,V2>

Direct Known Subclasses:

LogAnalytics.LogAnalyticsReducer, WordCount.WordCountReducer

public class GoraReducer<K1,V1,K2,V2 extends Persistent>
extends org.apache.hadoop.mapreduce.Reducer<K1,V1,K2,V2>

Base class for Gora based Reducers.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.mapreduce.Reducer

org.apache.hadoop.mapreduce.Reducer.Context

Constructor Summary

GoraReducer()

Method Summary

static <K1,V1,K2,V2 extends Persistent> void	initReducerJob(org.apache.hadoop.mapreduce.Job job, Class<? extends DataStore<K2,V2>> dataStoreClass, Class<K2> keyClass, Class<V2> persistentClass, Class<? extends GoraReducer<K1,V1,K2,V2>> reducerClass, boolean reuseObjects) Initializes the Reducer, and sets output parameters for the job.
static <K1,V1,K2,V2 extends Persistent> void	initReducerJob(org.apache.hadoop.mapreduce.Job job, DataStore<K2,V2> dataStore, Class<? extends GoraReducer<K1,V1,K2,V2>> reducerClass) Initializes the Reducer, and sets output parameters for the job.
static <K1,V1,K2,V2 extends Persistent> void	initReducerJob(org.apache.hadoop.mapreduce.Job job, DataStore<K2,V2> dataStore, Class<? extends GoraReducer<K1,V1,K2,V2>> reducerClass, boolean reuseObjects) Initializes the Reducer, and sets output parameters for the job.

Methods inherited from class org.apache.hadoop.mapreduce.Reducer

cleanup, reduce, run, setup

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

GoraReducer

public GoraReducer()

Method Detail

initReducerJob

public static <K1,V1,K2,V2 extends Persistent> void initReducerJob(org.apache.hadoop.mapreduce.Job job,
                                                                   Class<? extends DataStore<K2,V2>> dataStoreClass,
                                                                   Class<K2> keyClass,
                                                                   Class<V2> persistentClass,
                                                                   Class<? extends GoraReducer<K1,V1,K2,V2>> reducerClass,
                                                                   boolean reuseObjects)

Initializes the Reducer, and sets output parameters for the job.

Parameters:

job - the job to set the properties for

dataStoreClass - the datastore class

keyClass - output key class

persistentClass - output value class

reducerClass - the reducer class extending GoraReducer

reuseObjects - whether to reuse objects in serialization

initReducerJob

public static <K1,V1,K2,V2 extends Persistent> void initReducerJob(org.apache.hadoop.mapreduce.Job job,
                                                                   DataStore<K2,V2> dataStore,
                                                                   Class<? extends GoraReducer<K1,V1,K2,V2>> reducerClass)

Initializes the Reducer, and sets output parameters for the job.

Parameters:

job - the job to set the properties for

dataStore - the datastore as the output

reducerClass - the reducer class extending GoraReducer

initReducerJob

public static <K1,V1,K2,V2 extends Persistent> void initReducerJob(org.apache.hadoop.mapreduce.Job job,
                                                                   DataStore<K2,V2> dataStore,
                                                                   Class<? extends GoraReducer<K1,V1,K2,V2>> reducerClass,
                                                                   boolean reuseObjects)

Initializes the Reducer, and sets output parameters for the job.

Parameters:

job - the job to set the properties for

dataStore - the datastore as the output

reducerClass - the reducer class extending GoraReducer

reuseObjects - whether to reuse objects in serialization