org.apache.hadoop.mapred.lib
Class IdentityReducer<K,V>
java.lang.Object
org.apache.hadoop.mapred.MapReduceBase
org.apache.hadoop.mapred.lib.IdentityReducer<K,V>
- All Implemented Interfaces:
- Closeable, JobConfigurable, Reducer<K,V,K,V>
@InterfaceAudience.Public
@InterfaceStability.Stable
public class IdentityReducer<K,V>
- extends MapReduceBase
- implements Reducer<K,V,K,V>
Performs no reduction, writing all input values directly to the output.
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
IdentityReducer
public IdentityReducer()
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.
- Specified by:
reduce
in interface Reducer<K,V,K,V>
- Parameters:
key
- the key.values
- the list of values to reduce.output
- to collect keys and combined values.reporter
- facility to report progress.
- Throws:
IOException
Copyright © 2014 Apache Software Foundation. All Rights Reserved.