Module com.github.benmanes.caffeine

Package com.github.benmanes.caffeine.cache

Interface Weigher<K,V>

Type Parameters:

K - the type of keys

V - the type of values

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface Weigher<K,V>

Calculates the weights of cache entries. The total weight threshold is used to determine when an eviction is required.

Method Summary

Modifier and Type	Method	Description
static <K,V> Weigher<K,V>	boundedWeigher(Weigher<K,V> delegate)	Returns a weigher that enforces that the weight is non-negative.
static <K,V> Weigher<K,V>	singletonWeigher()	Returns a weigher where an entry has a weight of 1.
@org.checkerframework.checker.index.qual.NonNegative int	weigh(K key, V value)	Returns the weight of a cache entry.

Method Detail

weigh

@org.checkerframework.checker.index.qual.NonNegative int weigh(K key,
                                                               V value)

Returns the weight of a cache entry. There is no unit for entry weights; rather they are simply relative to each other.

Parameters:

key - the key to weigh

value - the value to weigh

Returns:

the weight of the entry; must be non-negative

singletonWeigher

static <K,V> Weigher<K,V> singletonWeigher()

Returns a weigher where an entry has a weight of 1.

Type Parameters:

K - the type of keys

V - the type of values

Returns:

a weigher where an entry has a weight of 1

boundedWeigher

static <K,V> Weigher<K,V> boundedWeigher(Weigher<K,V> delegate)

Returns a weigher that enforces that the weight is non-negative.

Type Parameters:

K - the type of keys

V - the type of values

Parameters:

delegate - the weigher to weighs the entry

Returns:

a weigher that enforces that the weight is non-negative