caches::LFUCachePolicy

LFU (Least frequently used) cache policy. More...

#include <lfu_cache_policy.hpp>

Inherits from caches::ICachePolicy< Key >

Public Types

	Name
using typename std::multimap< std::size_t, Key >::iterator	lfu_iterator

Public Functions

	Name
	LFUCachePolicy() =default
	~LFUCachePolicy() override =default
virtual void	Insert(const Key & key) override Handle element insertion in a cache.
virtual void	Touch(const Key & key) override Handle request to the key-element in a cache.
virtual void	Erase(const Key & key) override Handle element deletion from a cache.
virtual const Key &	ReplCandidate() const override Return a key of a replacement candidate.

Additional inherited members

Public Functions inherited from caches::ICachePolicy< Key >

	Name
virtual	~ICachePolicy() =default

Detailed Description

template <typename Key >
class caches::LFUCachePolicy;

LFU (Least frequently used) cache policy.

Template Parameters:

• Key Type of a key a policy works with

LFU policy in the case of replacement removes the least frequently used element.

Each access to an element in the cache increments internal counter (frequency) that represents how many times that particular key has been accessed by someone. When a replacement has to occur the LFU policy just takes a look onto keys' frequencies and remove the least used one. E.g. cache of two elements where A has been accessed 10 times and B – only 2. When you want to add a key C the LFU policy returns B as a replacement candidate.

Public Types Documentation

using lfu_iterator

using caches::LFUCachePolicy< Key >::lfu_iterator =  typename std::multimap<std::size_t, Key>::iterator;

Public Functions Documentation

function LFUCachePolicy

LFUCachePolicy() =default

function ~LFUCachePolicy

~LFUCachePolicy() override =default

function Insert

inline virtual void Insert(
    const Key & key
) override

Handle element insertion in a cache.

Parameters:

• key Key that should be used by the policy

Reimplements: caches::ICachePolicy::Insert

function Touch

inline virtual void Touch(
    const Key & key
) override

Handle request to the key-element in a cache.

Parameters:

• key

Reimplements: caches::ICachePolicy::Touch

function Erase

inline virtual void Erase(
    const Key & key
) override

Handle element deletion from a cache.

Parameters:

• key Key that should be used by the policy

Reimplements: caches::ICachePolicy::Erase

function ReplCandidate

inline virtual const Key & ReplCandidate() const override

Return a key of a replacement candidate.

Return: Replacement candidate according to selected policy

Reimplements: caches::ICachePolicy::ReplCandidate