| Modifier and Type | Method and Description |
|---|---|
Class<? extends Reducer<?,?,?,?>> |
JobContext.getCombinerClass()
Get the combiner class for the job.
|
Class<? extends Reducer<?,?,?,?>> |
JobContext.getReducerClass()
Get the
Reducer class for the job. |
| Modifier and Type | Method and Description |
|---|---|
void |
Job.setCombinerClass(Class<? extends Reducer> cls)
Set the combiner class for the job.
|
void |
Job.setReducerClass(Class<? extends Reducer> cls)
Set the
Reducer for the job. |
| Modifier and Type | Class and Description |
|---|---|
class |
ValueAggregatorCombiner<K1 extends WritableComparable<?>,V1 extends Writable>
This class implements the generic combiner of Aggregate.
|
class |
ValueAggregatorReducer<K1 extends WritableComparable<?>,V1 extends Writable>
This class implements the generic reducer of Aggregate.
|
| Modifier and Type | Class and Description |
|---|---|
class |
ChainReducer<KEYIN,VALUEIN,KEYOUT,VALUEOUT>
The ChainReducer class allows to chain multiple Mapper classes after a
Reducer within the Reducer task.
|
| Modifier and Type | Method and Description |
|---|---|
static void |
ChainReducer.setReducer(Job job,
Class<? extends Reducer> klass,
Class<?> inputKeyClass,
Class<?> inputValueClass,
Class<?> outputKeyClass,
Class<?> outputValueClass,
Configuration reducerConf)
Sets the
Reducer class to the chain job. |
| Modifier and Type | Class and Description |
|---|---|
class |
FieldSelectionReducer<K,V>
This class implements a reducer class that can be used to perform field
selections in a manner similar to unix cut.
|
| Modifier and Type | Class and Description |
|---|---|
class |
IntSumReducer<Key> |
class |
LongSumReducer<KEY> |
class |
WrappedReducer<KEYIN,VALUEIN,KEYOUT,VALUEOUT>
A
Reducer which wraps a given one to allow for custom
Reducer.Context implementations. |
Copyright © 2020 Apache Software Foundation. All rights reserved.