org.apache.giraph.master

Class AggregatorReduceOperation<A extends org.apache.hadoop.io.Writable>

java.lang.Object

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

org.apache.giraph.master.AggregatorReduceOperation<A>

Type Parameters:

A - Aggregation object type

All Implemented Interfaces:

GiraphConfigurationSettable, ReduceOperation<A,A>, org.apache.hadoop.io.Writable

public class AggregatorReduceOperation<A extends org.apache.hadoop.io.Writable>
extends ReduceSameTypeOperation<A>
implements GiraphConfigurationSettable

Translates aggregation operation to reduce operations.

Constructor Summary

Constructors

Constructor and Description
AggregatorReduceOperation() Constructor
AggregatorReduceOperation(Class<? extends Aggregator<A>> aggregatorClass, ImmutableClassesGiraphConfiguration<?,?,?> conf) Constructor

Method Summary

Modifier and Type	Method and Description
AggregatorReduceOperation<A>	createCopy() Creates copy of this object
A	createInitialValue() Return new reduced value which is neutral to reduce operation.
Class<? extends Aggregator<A>>	getAggregatorClass()
void	readFields(DataInput in)
A	reduce(A curValue, A valueToReduce) Add a new value.
void	setConf(ImmutableClassesGiraphConfiguration conf) Set the configuration to be used by this object.
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

AggregatorReduceOperation

public AggregatorReduceOperation()

Constructor

AggregatorReduceOperation

public AggregatorReduceOperation(Class<? extends Aggregator<A>> aggregatorClass,
                                 ImmutableClassesGiraphConfiguration<?,?,?> conf)

Constructor

Parameters:

aggregatorClass - Aggregator class

conf - Configuration

Method Detail

createInitialValue

public A createInitialValue()

Description copied from interface: ReduceOperation

Return new reduced value which is neutral to reduce operation.

Specified by:

createInitialValue in interface ReduceOperation<A extends org.apache.hadoop.io.Writable,A extends org.apache.hadoop.io.Writable>

Returns:

Neutral value

createCopy

public AggregatorReduceOperation<A> createCopy()

Creates copy of this object

Returns:

copy

getAggregatorClass

public Class<? extends Aggregator<A>> getAggregatorClass()

reduce

public A reduce(A curValue,
                A 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.

Specified by:

reduce in interface ReduceOperation<A extends org.apache.hadoop.io.Writable,A extends org.apache.hadoop.io.Writable>

Parameters:

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

valueToReduce - Single value to be reduced

Returns:

reduced value

setConf

public void setConf(ImmutableClassesGiraphConfiguration conf)

Description copied from interface: GiraphConfigurationSettable

Set the configuration to be used by this object.

Specified by:

setConf in interface GiraphConfigurationSettable

Parameters:

conf - Set configuration

write

public void write(DataOutput out)
           throws IOException

Specified by:

write in interface org.apache.hadoop.io.Writable

Throws:

IOException

readFields

public void readFields(DataInput in)
                throws IOException

Specified by:

readFields in interface org.apache.hadoop.io.Writable

Throws:

IOException