com.google.appengine.tools.mapreduce.mappers

Class KeyProjectionMapper<T>

java.lang.Object

com.google.appengine.tools.mapreduce.Worker<C>

com.google.appengine.tools.mapreduce.Mapper<T,T,Void>

com.google.appengine.tools.mapreduce.mappers.KeyProjectionMapper<T>

Type Parameters:

T - type input that is passed on as the key

All Implemented Interfaces:

Serializable

public class KeyProjectionMapper<T>
extends Mapper<T,T,Void>

A pass through mapper that passes the input to the output key.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
KeyProjectionMapper()

Method Summary

Methods

Modifier and Type	Method and Description
protected void	emit(O value) Syntactic sugar for getContext().emit(value)
void	map(T value) Processes a single input value, emitting output through the context returned by Worker.getContext() or emit(O).

Methods inherited from class com.google.appengine.tools.mapreduce.Mapper

emit

Methods inherited from class com.google.appengine.tools.mapreduce.Worker

allowSliceRetry, beginShard, beginSlice, endShard, endSlice, estimateMemoryRequirement, getContext, setContext

Methods inherited from class java.lang.Object

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

Constructor Detail

KeyProjectionMapper

public KeyProjectionMapper()

Method Detail

map

public void map(T value)

Processes a single input value, emitting output through the context returned by Worker.getContext() or emit(O).

emit

protected void emit(O value)

Syntactic sugar for getContext().emit(value)