org.apache.giraph.reducers.impl

Class MaxPairReducer<L extends org.apache.hadoop.io.Writable,R extends org.apache.hadoop.io.WritableComparable>

java.lang.Object

org.apache.giraph.reducers.ReduceSameTypeOperation<PairWritable<L,R>>

org.apache.giraph.reducers.impl.MaxPairReducer<L,R>

Type Parameters:

L - Type of the left value

R - Type of the right value

All Implemented Interfaces:

ReduceOperation<PairWritable<L,R>,PairWritable<L,R>>, org.apache.hadoop.io.Writable

public class MaxPairReducer<L extends org.apache.hadoop.io.Writable,R extends org.apache.hadoop.io.WritableComparable>
extends ReduceSameTypeOperation<PairWritable<L,R>>

Aggregating PairWritable<L, R>, by taking pair with largest second value.

Constructor Summary

Constructors

Constructor and Description
MaxPairReducer() Constructor used for deserialization only
MaxPairReducer(TypeOps<L> leftTypeOps, TypeOps<R> rightTypeOps) Constructor

Method Summary

Modifier and Type	Method and Description
PairWritable<L,R>	createInitialValue() Return new reduced value which is neutral to reduce operation.
void	readFields(DataInput in)
PairWritable<L,R>	reduce(PairWritable<L,R> curValue, PairWritable<L,R> valueToReduce) Add a new value.
void	write(DataOutput out)

Methods inherited from class org.apache.giraph.reducers.ReduceSameTypeOperation

reduceMerge

Methods inherited from class java.lang.Object

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

Constructor Detail

MaxPairReducer

public MaxPairReducer()

Constructor used for deserialization only

MaxPairReducer

public MaxPairReducer(TypeOps<L> leftTypeOps,
                      TypeOps<R> rightTypeOps)

Constructor

Parameters:

leftTypeOps - Left value TypeOps

rightTypeOps - Right value TypeOps

Method Detail

reduce

public PairWritable<L,R> reduce(PairWritable<L,R> curValue,
                                PairWritable<L,R> valueToReduce)

Description copied from interface: ReduceOperation

Add a new value. Needs to be commutative and associative Commonly, returned value should be same as curValue argument.

Parameters:

curValue - Partial value into which to reduce and store the result

valueToReduce - Single value to be reduced

Returns:

reduced value

createInitialValue

public PairWritable<L,R> createInitialValue()

Description copied from interface: ReduceOperation

Return new reduced value which is neutral to reduce operation.

Returns:

Neutral value

write

public void write(DataOutput out)
           throws IOException

Throws:

IOException

readFields

public void readFields(DataInput in)
                throws IOException

Throws:

IOException