| 程序包 | 说明 |
|---|---|
| org.apache.hadoop.contrib.index.mapred | |
| org.apache.hadoop.contrib.utils.join | |
| org.apache.hadoop.examples |
Hadoop example code.
|
| org.apache.hadoop.mapred |
A software framework for easily writing applications which process vast
amounts of data (multi-terabyte data-sets) parallelly on large clusters
(thousands of nodes) built of commodity hardware in a reliable, fault-tolerant
manner.
|
| org.apache.hadoop.mapred.lib |
Library of generally useful mappers, reducers, and partitioners.
|
| org.apache.hadoop.mapred.lib.aggregate |
Classes for performing various counting and aggregations.
|
| org.apache.hadoop.streaming |
Hadoop Streaming is a utility which allows users to create and run
Map-Reduce jobs with any executables (e.g.
|
| 限定符和类型 | 类和说明 |
|---|---|
class |
IndexUpdateCombiner
This combiner combines multiple intermediate forms into one intermediate
form.
|
class |
IndexUpdateReducer
This reducer applies to a shard the changes for it.
|
| 限定符和类型 | 类和说明 |
|---|---|
class |
DataJoinMapperBase
This abstract class serves as the base class for the mapper class of a data
join job.
|
class |
DataJoinReducerBase
This abstract class serves as the base class for the reducer class of a data
join job.
|
class |
JobBase
A common base implementing some statics collecting mechanisms that are
commonly used in a typical map/reduce job.
|
| 限定符和类型 | 类和说明 |
|---|---|
static class |
PiEstimator.PiReducer
Reducer class for Pi estimation.
|
class |
SleepJob
Dummy class for testing MR framefork.
|
| 限定符和类型 | 方法和说明 |
|---|---|
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. |
| 限定符和类型 | 方法和说明 |
|---|---|
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. |
| 构造器和说明 |
|---|
Task.OldCombinerRunner(Class<? extends Reducer<K,V,K,V>> cls,
JobConf conf,
Counters.Counter inputCounter,
Task.TaskReporter reporter) |
| 限定符和类型 | 类和说明 |
|---|---|
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. |
| 限定符和类型 | 方法和说明 |
|---|---|
static <K1,V1,K2,V2> |
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.
|
| 限定符和类型 | 类和说明 |
|---|---|
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.
|
| 限定符和类型 | 类和说明 |
|---|---|
class |
PipeCombiner |
class |
PipeReducer
A generic Reducer bridge.
|
Copyright © 2009 The Apache Software Foundation