com.helger.commons.collection.lru

Class LRUMap<KEYTYPE,VALUETYPE>

java.lang.Object

java.util.AbstractMap<K,V>

java.util.HashMap<K,V>

java.util.LinkedHashMap<KEYTYPE,VALUETYPE>

com.helger.commons.collection.lru.LRUMap<KEYTYPE,VALUETYPE>

Type Parameters:

KEYTYPE - Key type

VALUETYPE - Value type

All Implemented Interfaces:

Serializable, Cloneable, Map<KEYTYPE,VALUETYPE>

Direct Known Subclasses:

LoggingLRUMap

@NotThreadSafe
@UseDirectEqualsAndHashCode
public class LRUMap<KEYTYPE,VALUETYPE>
extends LinkedHashMap<KEYTYPE,VALUETYPE>

A special ordered map, that has an upper limit of contained elements. It is therefore a "Last Recently Used" map.

Author:

Philip Helger

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 and Description
LRUMap(int nMaxSize) Create a new object with the specified max size.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	equals(Object o)
int	getMaxSize()
int	hashCode()
protected void	onRemoveEldestEntry(int nSize, Map.Entry<KEYTYPE,VALUETYPE> aEldest) Protected method that is invoked every time the oldest entry is removed.
protected boolean	removeEldestEntry(Map.Entry<KEYTYPE,VALUETYPE> aEldest)
String	toString()

Methods inherited from class java.util.LinkedHashMap

clear, containsValue, get

Methods inherited from class java.util.HashMap

clone, containsKey, entrySet, isEmpty, keySet, put, putAll, remove, size, values

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Map

containsKey, entrySet, isEmpty, keySet, put, putAll, remove, size, values

Constructor Detail

LRUMap

public LRUMap(@Nonnegative
      int nMaxSize)

Create a new object with the specified max size.

Parameters:

nMaxSize - The maximum number of elements in this cache. May not be < 0.

Method Detail

getMaxSize

@Nonnegative
public final int getMaxSize()

Returns:

The maximum number of elements that can reside inside this object. Never < 0.

onRemoveEldestEntry

@OverrideOnDemand
protected void onRemoveEldestEntry(@Nonnegative
                                        int nSize,
                                        @Nonnull
                                        Map.Entry<KEYTYPE,VALUETYPE> aEldest)

Protected method that is invoked every time the oldest entry is removed.

Parameters:

nSize - Current size of the map. Always ≥ 0.

aEldest - The map entry that is removed. Never null.

removeEldestEntry

protected final boolean removeEldestEntry(@Nonnull
                        Map.Entry<KEYTYPE,VALUETYPE> aEldest)

Overrides:

removeEldestEntry in class LinkedHashMap<KEYTYPE,VALUETYPE>

equals

public boolean equals(Object o)

Specified by:

equals in interface Map<KEYTYPE,VALUETYPE>

Overrides:

equals in class AbstractMap<KEYTYPE,VALUETYPE>

hashCode

public int hashCode()

Specified by:

hashCode in interface Map<KEYTYPE,VALUETYPE>

Overrides:

hashCode in class AbstractMap<KEYTYPE,VALUETYPE>

toString

public String toString()

Overrides:

toString in class AbstractMap<KEYTYPE,VALUETYPE>