cachemere::policy::ConstraintCount< Key, KeyHash, Value > Class Template Reference

Count constraint. More...

#include <constraint_count.h>

Public Member Functions
	ConstraintCount (size_t maximum_count)
void	clear ()
	Clears the policy.
bool	can_add (const Key &key, const CacheItem &item)
	Determines whether an insertion candidate can be added into the cache. More...
bool	can_replace (const Key &key, const CacheItem &old_item, const CacheItem &new_item)
	Determines whether an item already in cache can be updated. More...
bool	is_satisfied ()
	Returns whether the constraint is satisfied. More...
void	update (size_t maximum_count)
	Update the cache constraint. More...
void	on_insert (const Key &key, const CacheItem &item)
	Insertion event handler. More...
void	on_evict (const Key &key, const CacheItem &item)
	Eviction event handler. More...
size_t	count () const
	Get the number of items currently in the cache. More...
size_t	maximum_count () const
	Get the maximum number of items allowed in cache. More...

Detailed Description

template<typename Key, typename KeyHash, typename Value>
class cachemere::policy::ConstraintCount< Key, KeyHash, Value >

Count constraint.

Use this when the constraint of the cache should be the number of items in cache.

Template Parameters

Key	The type of the keys used to identify items in the cache.
KeyHash	The type of the hasher used to hash item keys.
Value	The type of the values stored in the cache.

Member Function Documentation

can_add()

template<typename Key , typename KeyHash , typename Value >

bool cachemere::policy::ConstraintCount< K, KH, V >::can_add	(	const Key &	key,
		const CacheItem &	item
	)

Determines whether an insertion candidate can be added into the cache.

That is, whether the constraint would still be satisfied after inserting the candidate.

Parameters

key	The key of the insertion candidate.
item	The candidate item.

Returns

Whether the item can be added in cache.

can_replace()

template<typename Key , typename KeyHash , typename Value >

bool cachemere::policy::ConstraintCount< K, KH, V >::can_replace	(	const Key &	key,
		const CacheItem &	old_item,
		const CacheItem &	new_item
	)

Determines whether an item already in cache can be updated.

That is, whether the key can be updated to the new value while still satisfying the constraint.

Parameters

key	The key to be updated.
old_item	The current value of the key in cache.
new_item	The value that would replace the current value.

Returns

Whether the item can be replaced.

count()

template<class K , class KH , class V >

size_t cachemere::policy::ConstraintCount< K, KH, V >::count

Get the number of items currently in the cache.

Returns

The number of items in cache.

is_satisfied()

template<class K , class KH , class V >

bool cachemere::policy::ConstraintCount< K, KH, V >::is_satisfied

Returns whether the constraint is satisfied.

Used by the cache after a constraint update to compute how many items should be evicted, if any.

Returns

Whether the cache constraint is satisfied.

maximum_count()

template<class K , class KH , class V >

size_t cachemere::policy::ConstraintCount< K, KH, V >::maximum_count

Get the maximum number of items allowed in cache.

Returns

The maximum number of items allowed in cache.

on_evict()

template<typename Key , typename KeyHash , typename Value >

void cachemere::policy::ConstraintCount< K, KH, V >::on_evict	(	const Key &	key,
		const CacheItem &	item
	)

Eviction event handler.

Removes one from the number of items in cache.

Parameters

key	The key that was evicted.
item	The item that was evicted.

on_insert()

template<typename Key , typename KeyHash , typename Value >

void cachemere::policy::ConstraintCount< K, KH, V >::on_insert	(	const Key &	key,
		const CacheItem &	item
	)

Insertion event handler.

Adds one to the number of items in cache.

Parameters

key	The key of the inserted item.
item	The item that has been inserted in cache.

update()

template<class K , class KH , class V >

void cachemere::policy::ConstraintCount< K, KH, V >::update

(

size_t

maximum_count

)

Update the cache constraint.

Sets a new maximum count.

Parameters

maximum_count

The new number of items in cache.

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The documentation for this class was generated from the following files:

• include/cachemere/policy/constraint_count.h
• include/cachemere/policy/constraint_count.hpp