com.google.appengine.tools.mapreduce

Class MapOnlyMapper<I,O>

java.lang.Object

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

com.google.appengine.tools.mapreduce.MapOnlyMapper<I,O>

Type Parameters:

I - type of input received

O - type of intermediate values produced

All Implemented Interfaces:

Serializable

public abstract class MapOnlyMapper<I,O>
extends Worker<C>

Map function for Map only jobs. A map function processes input values one at a time and generates zero or more output values.

This class is really an interface that might be evolving. In order to avoid breaking users when we change the interface, we made it an abstract class.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
MapOnlyMapper()

Method Summary

Methods

Modifier and Type	Method and Description
protected void	emit(O value) Syntactic sugar for getContext().emit(value)
static <I,Void,V> MapOnlyMapper<I,V>	forMapper(Mapper<I,Void,V> mapper) Returns a MapOnlyMapper for a given Mapper passing only the values to the output.
abstract void	map(I 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.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

MapOnlyMapper

public MapOnlyMapper()

Method Detail

forMapper

public static <I,Void,V> MapOnlyMapper<I,V> forMapper(Mapper<I,Void,V> mapper)

Returns a MapOnlyMapper for a given Mapper passing only the values to the output.

map

public abstract void map(I 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)