kitecore/io.github.yuroyami.kitecore.structures/LruCache

LruCache

class LruCache<K, V>(val maxSize: Int)

A fixed-capacity cache that evicts the least recently used entry first.

get, getOrPut on a hit, and put mark the entry most recently used; containsKey, keys, and toMap do not affect recency. When put inserts a new key while the cache already holds maxSize entries, the least recently used entry is evicted before the insert. All operations run in amortized constant time. Backed by LinkedHashMap.

This class is not thread-safe.

Type Parameters

K

the key type.

V

the value type.

Throws

IllegalArgumentException

if maxSize is not positive.

Constructors

constructor(maxSize: Int)

Creates an empty cache that holds at most maxSize entries.

Properties

val maxSize: Int

The maximum number of entries the cache holds. Always positive.

The number of entries currently in the cache, from 0 to maxSize.

Functions

fun clear()

Removes every entry from the cache.

fun containsKey(key: K): Boolean

Returns true if key has an entry in the cache. Does not affect recency.

fun get(key: K): V?

Returns the value for key and marks it most recently used, or returns null if the key is absent.

fun getOrPut(key: K, defaultValue: () -> V): V

Returns the value for key if present, otherwise computes it with defaultValue, stores it, and returns it.

fun keys(): Set<K>

Returns a snapshot of the keys in eviction order, least recently used first. Does not affect recency.

fun put(key: K, value: V): V?

Stores value under key and marks the entry most recently used.

fun remove(key: K): V?

Removes the entry for key and returns its value, or returns null if the key is absent.

fun toMap(): Map<K, V>

Returns a snapshot of the entries in eviction order, least recently used first. Does not affect recency.