org.apache.hadoop.mapred.lib
Class InverseMapper<K,V>
java.lang.Object
org.apache.hadoop.mapred.MapReduceBase
org.apache.hadoop.mapred.lib.InverseMapper<K,V>
- All Implemented Interfaces:
- Closeable, JobConfigurable, Mapper<K,V,V,K>
public class InverseMapper<K,V>
- extends MapReduceBase
- implements Mapper<K,V,V,K>
A Mapper that swaps keys and values.
| Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
InverseMapper
public InverseMapper()
map
public void map(K key,
V value,
OutputCollector<V,K> output,
Reporter reporter)
throws IOException
- The inverse function. Input keys and values are swapped.
- Specified by:
map in interface Mapper<K,V,V,K>
- Parameters:
key - the input key.value - the input value.output - collects mapped keys and values.reporter - facility to report progress.
- Throws:
IOException
Copyright © 2009 The Apache Software Foundation