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.

@ThreadSafe
 @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 and Description
static <K,V> Weigher<K,V>	bounded(Weigher<K,V> delegate) Returns a weigher that enforces that the weight is non-negative.
static <K,V> Weigher<K,V>	singleton() Returns a weigher where an entry has a weight of 1.
int	weigh(K key, V value) Returns the weight of a cache entry.

Method Detail

weigh

@Nonnegative
int weigh(@Nonnull
                       K key,
                       @Nonnull
                       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

singleton

@Nonnull
static <K,V> Weigher<K,V> singleton()

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

bounded

@Nonnull
static <K,V> Weigher<K,V> bounded(@Nonnull
                                           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 that weighs the entry

Returns:

a weigher that enforces that the weight is non-negative