org.semanticweb.elk.util.collections

Class CapacityBalancingEvictor<E>

java.lang.Object

org.semanticweb.elk.util.collections.AbstractEvictor<E>

org.semanticweb.elk.util.collections.RecencyEvictor<E>

org.semanticweb.elk.util.collections.CapacityBalancingEvictor<E>

Type Parameters:

E - The type of the elements.

All Implemented Interfaces:

Evictor<E>, HasStats

public class CapacityBalancingEvictor<E>
extends RecencyEvictor<E>

An RecencyEvictor that balances its capacity so that some proportion of repeatedly added elements is not evicted. This proportion is called balance.

Implementation idea

A query age of an element is the number of times some other element was added since this element was added last time. This is an overestimation of the position of this element in the recency queue if it had infinite capacity. Consider a sequence of numbers that contains one number for each time add was called on an element that was added before. This number would be its position in infinite recency queue. Median of this sequence is the capacity with which half of the elements would be not evicted. Analogously, x-percentile of this sequence is the capacity at which x% of the elements would not be evicted. TODO: The records about query ages grow indefinitely, which is a memory leak.

Author:

Peter Skocovsky

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	CapacityBalancingEvictor.Builder
protected static class	CapacityBalancingEvictor.ProtectedBuilder<B extends CapacityBalancingEvictor.ProtectedBuilder<B>>
protected class	CapacityBalancingEvictor.Stats

Field Summary

Fields inherited from class org.semanticweb.elk.util.collections.AbstractEvictor

stats

Method Summary

Modifier and Type	Method and Description
void	add(E element) Add the provided element.
static CapacityBalancingEvictor.Builder	builder()
int	getNumberOfDifferentQueries()

Methods inherited from class org.semanticweb.elk.util.collections.RecencyEvictor

evict, getCapacity, setCapacity, size

Methods inherited from class org.semanticweb.elk.util.collections.AbstractEvictor

addAndEvict, addAndEvict, evict, getStats

Methods inherited from class java.lang.Object

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

Method Detail

add

public void add(E element)

Description copied from interface: Evictor

Add the provided element.

Specified by:

add in interface Evictor<E>

Overrides:

add in class RecencyEvictor<E>

Parameters:

element - The added element.

getNumberOfDifferentQueries

@Stat(name="nDifferentQueries")
public int getNumberOfDifferentQueries()

builder

public static CapacityBalancingEvictor.Builder builder()