Package org.apache.dubbo.common.utils

Class LRU2Cache<K,V>

java.lang.Object

java.util.AbstractMap<K,V>

java.util.HashMap<K,V>

java.util.LinkedHashMap<K,V>

org.apache.dubbo.common.utils.LRU2Cache<K,V>

All Implemented Interfaces:

Serializable, Cloneable, Map<K,V>, SequencedMap<K,V>

public class LRU2Cache<K,V>
extends LinkedHashMap<K,V>

LRU-2

When the data accessed for the first time, add it to history list. If the size of history list reaches max capacity, eliminate the earliest data (first in first out). When the data already exists in the history list, and be accessed for the second time, then it will be put into cache.

TODO, consider replacing with ConcurrentHashMap to improve performance under concurrency

See Also:

• Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class java.util.AbstractMap

AbstractMap.SimpleEntry<K,V>, AbstractMap.SimpleImmutableEntry<K,V>

Constructor Summary

Constructors

Constructor	Description
LRU2Cache()
LRU2Cache(int maxCapacity)

Method Summary

Modifier and Type	Method	Description
void	clear()
V	computeIfAbsent(K key, Function<? super K,? extends V> fn)
boolean	containsKey(Object key)
V	get(Object key)
int	getMaxCapacity()
V	put(K key, V value)
V	remove(Object key)
void	setMaxCapacity(int maxCapacity)
int	size()

Methods inherited from class java.util.LinkedHashMap

containsValue, entrySet, forEach, getOrDefault, keySet, newLinkedHashMap, putFirst, putLast, replaceAll, reversed, sequencedEntrySet, sequencedKeySet, sequencedValues, values

Methods inherited from class java.util.HashMap

clone, compute, computeIfPresent, isEmpty, merge, newHashMap, putAll, putIfAbsent, remove, replace, replace

Methods inherited from class java.util.AbstractMap

equals, hashCode, toString

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Map

compute, computeIfPresent, equals, hashCode, isEmpty, merge, putAll, putIfAbsent, remove, replace, replace

Methods inherited from interface java.util.SequencedMap

firstEntry, lastEntry, pollFirstEntry, pollLastEntry

Constructor Details

LRU2Cache

public LRU2Cache()

LRU2Cache

public LRU2Cache(int maxCapacity)

Method Details

containsKey

public boolean containsKey(Object key)

Specified by:

containsKey in interface Map<K,V>

Overrides:

containsKey in class HashMap<K,V>

get

public V get(Object key)

Specified by:

get in interface Map<K,V>

Overrides:

get in class LinkedHashMap<K,V>

put

public V put(K key,
 V value)

Specified by:

put in interface Map<K,V>

Overrides:

put in class HashMap<K,V>

computeIfAbsent

public V computeIfAbsent(K key,
 Function<? super K,? extends V> fn)

Specified by:

computeIfAbsent in interface Map<K,V>

Overrides:

computeIfAbsent in class HashMap<K,V>

remove

public V remove(Object key)

Specified by:

remove in interface Map<K,V>

Overrides:

remove in class HashMap<K,V>

size

public int size()

Specified by:

size in interface Map<K,V>

Overrides:

size in class HashMap<K,V>

clear

public void clear()

Specified by:

clear in interface Map<K,V>

Overrides:

clear in class LinkedHashMap<K,V>

getMaxCapacity

public int getMaxCapacity()

setMaxCapacity

public void setMaxCapacity(int maxCapacity)