org.apache.hadoop.hbase.util

Class LossyCounting

java.lang.Object

org.apache.hadoop.hbase.util.LossyCounting

@InterfaceAudience.Private
public class LossyCounting
extends Object

LossyCounting utility, bounded data structure that maintains approximate high frequency elements in data stream. Bucket size is 1 / error rate. (Error rate is 0.02 by default) Lemma If element
does not appear in set, then is frequency is less than e * N (N is total element counts until now.) Based on paper: http://www.vldb.org/conf/2002/S10P03.pdf

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	LossyCounting.LossyCountingListener

Constructor Summary

Constructors

Constructor and Description
LossyCounting(String name, org.apache.hadoop.conf.Configuration conf, LossyCounting.LossyCountingListener listener)
LossyCounting(String name, double errorRate, LossyCounting.LossyCountingListener listener)

Method Summary

Modifier and Type	Method and Description
void	add(String key)
boolean	contains(String key)
long	getBucketSize()
long	getCurrentTerm()
long	getDataSize()
Set<String>	getElements()

Methods inherited from class java.lang.Object

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

Constructor Detail

LossyCounting

public LossyCounting(String name,
                     double errorRate,
                     LossyCounting.LossyCountingListener listener)

LossyCounting

public LossyCounting(String name,
                     org.apache.hadoop.conf.Configuration conf,
                     LossyCounting.LossyCountingListener listener)

Method Detail

add

public void add(String key)

getBucketSize

public long getBucketSize()

getDataSize

public long getDataSize()

contains

public boolean contains(String key)

getElements

public Set<String> getElements()

getCurrentTerm

public long getCurrentTerm()