com.clearspring.analytics.stream

Class ConcurrentStreamSummary<T>

java.lang.Object

com.clearspring.analytics.stream.ConcurrentStreamSummary<T>

Type Parameters:

T - type of data in the stream to be summarized

All Implemented Interfaces:

ITopK<T>

public class ConcurrentStreamSummary<T>
extends Object
implements ITopK<T>

Based on the Space-Saving algorithm and the Stream-Summary data structure as described in: Efficient Computation of Frequent and Top-k Elements in Data Streams by Metwally, Agrawal, and Abbadi

Ideally used in multithreaded applications, otherwise see StreamSummary

Author:

Eric Vlaanderen

Constructor Summary

Constructors

Constructor and Description
ConcurrentStreamSummary(int capacity)

Method Summary

Methods

Modifier and Type	Method and Description
boolean	offer(T element) offer a single element to the top.
boolean	offer(T element, int incrementCount) offer a single element to the top and increment the count for that element by incrementCount.
List<T>	peek(int k)
List<ScoredItem<T>>	peekWithScores(int k)
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

ConcurrentStreamSummary

public ConcurrentStreamSummary(int capacity)

Method Detail

offer

public boolean offer(T element)

Description copied from interface: ITopK

offer a single element to the top.

Specified by:

offer in interface ITopK<T>

Parameters:

element - - the element to add to the top

Returns:

false if the element was already in the top

offer

public boolean offer(T element,
            int incrementCount)

Description copied from interface: ITopK

offer a single element to the top and increment the count for that element by incrementCount.

Specified by:

offer in interface ITopK<T>

Parameters:

element - - the element to add to the top

incrementCount - - the increment count for the given count

Returns:

false if the element was already in the top

toString

public String toString()

Overrides:

toString in class Object

peek

public List<T> peek(int k)

Specified by:

peek in interface ITopK<T>

Returns:

top k elements offered (may be an approximation)

peekWithScores

public List<ScoredItem<T>> peekWithScores(int k)