com.github.benmanes.caffeine.cache.simulator.policy.two_queue

Class TwoQueuePolicy

java.lang.Object

com.github.benmanes.caffeine.cache.simulator.policy.two_queue.TwoQueuePolicy

All Implemented Interfaces:

Policy, Policy.KeyOnlyPolicy

public final class TwoQueuePolicy
extends Object
implements Policy.KeyOnlyPolicy

The 2Q algorithm. This algorithm uses a queue for items that are seen once (IN), a queue for items seen multiple times (MAIN), and a non-resident queue for evicted items that are being monitored (OUT). The maximum size of the IN and OUT queues must be tuned with the authors recommending 20% and 50% of the maximum size, respectively.

This implementation is based on the pseudo code provided by the authors in their paper 2Q: A Low Overhead High Performance Buffer Management Replacement Algorithm. For consistency with other policies, this version places the next item to be removed at the head and most recently added at the tail of the queue.

Nested Class Summary

Nested classes/interfaces inherited from interface com.github.benmanes.caffeine.cache.simulator.policy.Policy

Policy.Characteristic, Policy.KeyOnlyPolicy, Policy.PolicySpec

Constructor Summary

Constructors

Constructor and Description
TwoQueuePolicy(Config config)

Method Summary

Modifier and Type	Method and Description
void	record(long key)
PolicyStats	stats() Returns the cache efficiency statistics.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.github.benmanes.caffeine.cache.simulator.policy.Policy.KeyOnlyPolicy

record

Methods inherited from interface com.github.benmanes.caffeine.cache.simulator.policy.Policy

finished, name

Constructor Detail

TwoQueuePolicy

public TwoQueuePolicy(Config config)

Method Detail

record

public void record(long key)

Specified by:

record in interface Policy.KeyOnlyPolicy

stats

public PolicyStats stats()

Description copied from interface: Policy

Returns the cache efficiency statistics.

Specified by:

stats in interface Policy