Top Description Inners Fields Constructors Methods

org.springframework.util

public final Class ConcurrentLruCache<K, V>

Class Inheritance

extends Object

java.lang.Object
org.springframework.util.ConcurrentLruCache

Annotations

@SuppressWarnings:unchecked

Type Parameters

<K>: the type of the key used for cache retrieval
<V>: the type of the cached values, does not allow null values

Imports

java.util.Queue, java.util.concurrent.ConcurrentHashMap, .ConcurrentLinkedQueue, .ConcurrentMap, java.util.concurrent.atomic.AtomicInteger, .AtomicLongArray, .AtomicReference, .AtomicReferenceArray, java.util.concurrent.locks.Lock, .ReentrantLock, java.util.function.Function, org.springframework.lang.Nullable

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

This is a simplified, opinionated implementation of an LRU cache for internal use in Spring Framework. It is inspired from ConcurrentLinkedHashMap.

Read and write operations are internally recorded in dedicated buffers, then drained at chosen times to avoid contention.

Authors: Brian Clozel, Ben Manes
Since: 5.3
See Also: get(Object)

Nested and Inner Type Summary

Modifier and Type	Class and Description
private class	ConcurrentLruCache.AddTask Write operation recorded when a new entry is added to the cache.
private static record	ConcurrentLruCache.CacheEntry<V>
private static enum	ConcurrentLruCache.CacheEntryState
private static enum	ConcurrentLruCache.DrainStatus
private static class	ConcurrentLruCache.EvictionQueue<K, V>
private static class	ConcurrentLruCache.Node<K, V>
private static class	ConcurrentLruCache.ReadOperations<K, V>
private class	ConcurrentLruCache.RemovalTask Write operation recorded when an entry is removed to the cache.
private static class	ConcurrentLruCache.WriteOperations

Field Summary

Modifier and Type	Field and Description
private final ConcurrentMap<K, ConcurrentLruCache.Node<K, V>>	cache
private final int	capacity
private final AtomicInteger	currentSize
private final AtomicReference<ConcurrentLruCache.DrainStatus>	drainStatus
private final Lock	evictionLock
private final ConcurrentLruCache.EvictionQueue<K, V>	evictionQueue
private final Function<K, V>	generator
private final ConcurrentLruCache.ReadOperations<K, V>	readOperations
private final ConcurrentLruCache.WriteOperations	writeOperations

Constructor Summary

Access	Constructor and Description
public	ConcurrentLruCache(int the maximum number of entries in the cache (0 indicates no caching, always generating a new value) capacity, Function<K, V> a function to generate a new value for a given key generator) Create a new cache instance with the given capacity and generator function.
private	ConcurrentLruCache(int capacity, Function<K, V> generator, int concurrencyLevel)

Method Summary

Modifier and Type	Method and Description
public int	capacity() Return the maximum number of entries in the cache.
public void	clear() Immediately remove all entries from this cache.
public boolean	Returns: `true` if the key is present, `false` if there was no matching key contains(K the key to check for key) Determine whether the given key is present in this cache.
private void	drainOperations()
public V	Returns: the cached or newly generated value get(K the key to retrieve the entry for key) Retrieve an entry from the cache, potentially triggering generation of the value.
private void	markAsRemoved(ConcurrentLruCache.Node<K, V> node)
private void	markForRemoval(ConcurrentLruCache.Node<K, V> node)
private void	processRead(ConcurrentLruCache.Node<K, V> node)
private void	processWrite(Runnable task)
private void	put(K key, V value)
public boolean	Returns: `true` if the key was present before, `false` if there was no matching key remove(K the key to evict the entry for key) Immediately remove the given key and any associated value.
public int	size() Return the current size of the cache.
public int	sizeLimit() Deprecated since 6.0. in favor of `capacity()` as of 6.0. Return the maximum number of entries in the cache.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait