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org.apache.crunch.fn
Class ExtractKeyFn<K,V>

java.lang.Object
  org.apache.crunch.DoFn<S,T>
      org.apache.crunch.MapFn<V,Pair<K,V>>
          org.apache.crunch.fn.ExtractKeyFn<K,V>

All Implemented Interfaces:

Serializable

public class ExtractKeyFn<K,V>
extends MapFn<V,Pair<K,V>>

Wrapper function for converting a MapFn into a key-value pair that is used to convert from a PCollection<V> to a PTable<K, V>.

See Also:

Serialized Form

Constructor Summary

ExtractKeyFn(MapFn<V,K> mapFn)

Method Summary

void	initialize() Called during the setup of the MapReduce job this DoFn is associated with.
Pair<K,V>	map(V input) Maps the given input into an instance of the output type.

Methods inherited from class org.apache.crunch.MapFn

process, scaleFactor

Methods inherited from class org.apache.crunch.DoFn

cleanup, configure, setConfigurationForTest, setContext

Methods inherited from class java.lang.Object

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

Constructor Detail

ExtractKeyFn

public ExtractKeyFn(MapFn<V,K> mapFn)

Method Detail

initialize

public void initialize()

Description copied from class: DoFn

Called during the setup of the MapReduce job this DoFn is associated with. Subclasses may override this method to do appropriate initialization.

Overrides:

initialize in class DoFn<V,Pair<K,V>>

map

public Pair<K,V> map(V input)

Description copied from class: MapFn

Maps the given input into an instance of the output type.

Specified by:

map in class MapFn<V,Pair<K,V>>