org.apache.giraph.reducers.impl

Class MaxReduce<T extends org.apache.hadoop.io.WritableComparable>

java.lang.Object

org.apache.giraph.reducers.ReduceSameTypeOperation<T>

org.apache.giraph.reducers.impl.MaxReduce<T>

Type Parameters:

T - Value type

All Implemented Interfaces:

ReduceOperation<T,T>, org.apache.hadoop.io.Writable

public class MaxReduce<T extends org.apache.hadoop.io.WritableComparable>
extends ReduceSameTypeOperation<T>

Reducer for calculating max of values

Field Summary

Fields

Modifier and Type	Field and Description
static MaxReduce<org.apache.hadoop.io.DoubleWritable>	DOUBLE DoubleWritable specialization
static MaxReduce<org.apache.hadoop.io.IntWritable>	INT IntWritable specialization
static MaxReduce<org.apache.hadoop.io.LongWritable>	LONG LongWritable specialization

Constructor Summary

Constructors

Constructor and Description
MaxReduce() Constructor used for deserialization only
MaxReduce(NumericTypeOps<T> typeOps) Constructor

Method Summary

Modifier and Type	Method and Description
T	createInitialValue() Return new reduced value which is neutral to reduce operation.
void	readFields(DataInput in)
T	reduce(T curValue, T 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

Field Detail

DOUBLE

public static final MaxReduce<org.apache.hadoop.io.DoubleWritable> DOUBLE

DoubleWritable specialization

LONG

public static final MaxReduce<org.apache.hadoop.io.LongWritable> LONG

LongWritable specialization

INT

public static final MaxReduce<org.apache.hadoop.io.IntWritable> INT

IntWritable specialization

Constructor Detail

MaxReduce

public MaxReduce()

Constructor used for deserialization only

MaxReduce

public MaxReduce(NumericTypeOps<T> typeOps)

Constructor

Parameters:

typeOps - Value type operations

Method Detail

createInitialValue

public T createInitialValue()

Description copied from interface: ReduceOperation

Return new reduced value which is neutral to reduce operation.

Returns:

Neutral value

reduce

public T reduce(T curValue,
                T 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

write

public void write(DataOutput out)
           throws IOException

Throws:

IOException

readFields

public void readFields(DataInput in)
                throws IOException

Throws:

IOException