org.apache.hadoop.mapred.lib.aggregate

类 DoubleValueSum

java.lang.Object

org.apache.hadoop.mapred.lib.aggregate.DoubleValueSum

所有已实现的接口:

ValueAggregator

public class DoubleValueSum
extends Object
implements ValueAggregator

This class implements a value aggregator that sums up a sequence of double values.

构造器概要

构造器

构造器和说明
DoubleValueSum() The default constructor

方法概要

方法

限定符和类型	方法和说明
void	addNextValue(double val) add a value to the aggregator
void	addNextValue(Object val) add a value to the aggregator
ArrayList<String>	getCombinerOutput()
String	getReport()
double	getSum()
void	reset() reset the aggregator

从类继承的方法 java.lang.Object

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

构造器详细资料

DoubleValueSum

public DoubleValueSum()

The default constructor

方法详细资料

addNextValue

public void addNextValue(Object val)

add a value to the aggregator

指定者:

addNextValue 在接口中 ValueAggregator

参数:

val - an object whose string representation represents a double value.

addNextValue

public void addNextValue(double val)

add a value to the aggregator

参数:

val - a double value.

getReport

public String getReport()

指定者:

getReport 在接口中 ValueAggregator

返回:

the string representation of the aggregated value

getSum

public double getSum()

返回:

the aggregated value

reset

public void reset()

reset the aggregator

指定者:

reset 在接口中 ValueAggregator

getCombinerOutput

public ArrayList<String> getCombinerOutput()

指定者:

getCombinerOutput 在接口中 ValueAggregator

返回:

return an array of one element. The element is a string representation of the aggregated value. The return value is expected to be used by the a combiner.