org.apache.hadoop.mapred.lib

类 IdentityReducer<K,V>

java.lang.Object

org.apache.hadoop.mapred.MapReduceBase

org.apache.hadoop.mapred.lib.IdentityReducer<K,V>

所有已实现的接口:

Closeable, AutoCloseable, JobConfigurable, Reducer<K,V,K,V>

public class IdentityReducer<K,V>
extends MapReduceBase
implements Reducer<K,V,K,V>

Performs no reduction, writing all input values directly to the output.

构造器概要

构造器

构造器和说明
IdentityReducer()

方法概要

方法

限定符和类型	方法和说明
void	reduce(K key, Iterator<V> values, OutputCollector<K,V> output, Reporter reporter) Writes all keys and values directly to output.

从类继承的方法 org.apache.hadoop.mapred.MapReduceBase

close, configure

从类继承的方法 java.lang.Object

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

从接口继承的方法 org.apache.hadoop.mapred.JobConfigurable

configure

从接口继承的方法 java.io.Closeable

close

构造器详细资料

IdentityReducer

public IdentityReducer()

方法详细资料

reduce

public void reduce(K key,
          Iterator<V> values,
          OutputCollector<K,V> output,
          Reporter reporter)
            throws IOException

Writes all keys and values directly to output.

指定者:

reduce 在接口中 Reducer<K,V,K,V>

参数:

key - the key.

values - the list of values to reduce.

output - to collect keys and combined values.

reporter - facility to report progress.

抛出:

IOException