org.springframework.util

Class ConcurrentLruCache<K,V>

java.lang.Object

org.springframework.util.ConcurrentLruCache<K,V>

Type Parameters:

K - the type of the key used for cache retrieval

V - the type of the cached values

public class ConcurrentLruCache<K,V>
extends Object

Simple LRU (Least Recently Used) cache, bounded by a specified cache limit.

This implementation is backed by a ConcurrentHashMap for storing the cached values and a ConcurrentLinkedDeque for ordering the keys and choosing the least recently used key when the cache is at full capacity.

Since:

5.3

Author:

Brian Clozel, Juergen Hoeller

See Also:

get(K)

Constructor Summary

Constructors

Constructor and Description
ConcurrentLruCache(int sizeLimit, Function<K,V> generator) Create a new cache instance with the given limit and generator function.

Method Summary

Modifier and Type	Method and Description
void	clear() Immediately remove all entries from this cache.
boolean	contains(K key) Determine whether the given key is present in this cache.
V	get(K key) Retrieve an entry from the cache, potentially triggering generation of the value.
boolean	remove(K key) Immediately remove the given key and any associated value.
int	size() Return the current size of the cache.
int	sizeLimit() Return the the maximum number of entries in the cache (0 indicates no caching, always generating a new value).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ConcurrentLruCache

public ConcurrentLruCache(int sizeLimit,
                          Function<K,V> generator)

Create a new cache instance with the given limit and generator function.

Parameters:

sizeLimit - the maximum number of entries in the cache (0 indicates no caching, always generating a new value)

generator - a function to generate a new value for a given key

Method Detail

get

public V get(K key)

Retrieve an entry from the cache, potentially triggering generation of the value.

Parameters:

key - the key to retrieve the entry for

Returns:

the cached or newly generated value

contains

public boolean contains(K key)

Determine whether the given key is present in this cache.

Parameters:

key - the key to check for

Returns:

true if the key is present, false if there was no matching key

remove

public boolean remove(K key)

Immediately remove the given key and any associated value.

Parameters:

key - the key to evict the entry for

Returns:

true if the key was present before, false if there was no matching key

clear

public void clear()

Immediately remove all entries from this cache.

size

public int size()

Return the current size of the cache.

See Also:

sizeLimit()

sizeLimit

public int sizeLimit()

Return the the maximum number of entries in the cache (0 indicates no caching, always generating a new value).

See Also:

size()