org.apache.hadoop.mapred.lib.aggregate

类 UniqValueCount

java.lang.Object

org.apache.hadoop.mapred.lib.aggregate.UniqValueCount

所有已实现的接口:

ValueAggregator

public class UniqValueCount
extends Object
implements ValueAggregator

This class implements a value aggregator that dedupes a sequence of objects.

构造器概要

构造器

构造器和说明
UniqValueCount() the default constructor
UniqValueCount(long maxNum) constructor

方法概要

方法

限定符和类型	方法和说明
void	addNextValue(Object val) add a value to the aggregator
ArrayList	getCombinerOutput()
String	getReport()
Set	getUniqueItems()
void	reset() reset the aggregator
long	setMaxItems(long n) Set the limit on the number of unique values

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

UniqValueCount

public UniqValueCount()

the default constructor

UniqValueCount

public UniqValueCount(long maxNum)

constructor

参数:

maxNum - the limit in the number of unique values to keep.

方法详细资料

setMaxItems

public long setMaxItems(long n)

Set the limit on the number of unique values

参数:

n - the desired limit on the number of unique values

返回:

the new limit on the number of unique values

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.

getReport

public String getReport()

指定者:

getReport 在接口中 ValueAggregator

返回:

return the number of unique objects aggregated

getUniqueItems

public Set getUniqueItems()

返回:

the set of the unique objects

reset

public void reset()

reset the aggregator

指定者:

reset 在接口中 ValueAggregator

getCombinerOutput

public ArrayList getCombinerOutput()

指定者:

getCombinerOutput 在接口中 ValueAggregator

返回:

return an array of the unique objects. The return value is expected to be used by the a combiner.