org.apache.giraph.reducers.impl

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

java.lang.Object

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

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

Type Parameters:

T - Value type

All Implemented Interfaces:

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

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

Reducer for calculating min of values

Field Summary

Fields

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

Constructor Summary

Constructors

Constructor and Description
MinReduce() Constructor used for deserialization only
MinReduce(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 MinReduce<org.apache.hadoop.io.DoubleWritable> DOUBLE

DoubleWritable specialization

LONG

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

LongWritable specialization

INT

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

IntWritable specialization

Constructor Detail

MinReduce

public MinReduce()

Constructor used for deserialization only

MinReduce

public MinReduce(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