com.fasterxml.jackson.databind.util

Class LRUMap<K,V>

java.lang.Object

com.fasterxml.jackson.databind.util.LRUMap<K,V>

All Implemented Interfaces:

java.io.Serializable

public class LRUMap<K,V>
extends java.lang.Object
implements java.io.Serializable

Helper for simple bounded maps used for reusing lookup values.

Note that serialization behavior is such that contents are NOT serialized, on assumption that all use cases are for caching where persistence does not make sense. The only thing serialized is the cache size of Map.

NOTE: since version 2.4.2, this is NOT an LRU-based at all; reason being that it is not possible to use JDK components that do LRU _AND_ perform well wrt synchronization on multi-core systems. So we choose efficient synchronization over potentially more efficient handling of entries.

And yes, there are efficient LRU implementations such as concurrentlinkedhashmap; but at this point we really try to keep external deps to minimum. But perhaps a shaded variant may be used one day.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
LRUMap(int initialEntries, int maxEntries)

Method Summary

Modifier and Type	Method and Description
void	clear()
V	get(java.lang.Object key)
V	put(K key, V value)
V	putIfAbsent(K key, V value)
int	size()

Methods inherited from class java.lang.Object

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

Constructor Detail

LRUMap

public LRUMap(int initialEntries,
              int maxEntries)

Method Detail

put

public V put(K key,
             V value)

putIfAbsent

public V putIfAbsent(K key,
                     V value)

Since:

2.5

get

public V get(java.lang.Object key)

clear

public void clear()

size

public int size()