de.tsl2.nano.collection

Class ExpiringMap<K,V>

java.lang.Object

java.util.AbstractMap<K,V>

java.util.HashMap<K,V>

java.util.LinkedHashMap<K,V>

de.tsl2.nano.collection.ExpiringMap<K,V>

All Implemented Interfaces:

Serializable, Cloneable, Map<K,V>

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

map holding entries with a lifecycle defined by a timeout. on adding elements, old elements may be removed. useful for in-memory caches. if you define a timeout of -1, the expiration functionality will be switched off.

Note-1: the LinkedHashMap implementation provides an accessOrder (see it's constructors) and an unimplemented LinkedHashMap.removeEldestEntry(java.util.Map.Entry) - these are not usable for our cache.

Note-2: As the capacity() evaluation is only be accessible through pure-performance reflection, we may use our timeout variable as shrink()ing frequency.

Version:

$Revision$

Author:

Tom

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
ExpiringMap(int initialCapacity, float loadFactor, boolean accessOrder, long timeout) constructor
ExpiringMap(int initialCapacity, float loadFactor, long timeout) constructor
ExpiringMap(int initialCapacity, long timeout) constructor
ExpiringMap(long timeout) constructor
ExpiringMap(Map<? extends K,? extends V> m, long timeout) constructor

Method Summary

Modifier and Type	Method and Description
void	clear()
V	get(Object key)
protected void	init(long timeout) creates the touch-time table
V	put(K key, V value)
V	remove(Object key)
protected void	shrink() does the thing and removes expired objects.

Methods inherited from class java.util.LinkedHashMap

containsValue, entrySet, forEach, getOrDefault, keySet, removeEldestEntry, replaceAll, values

Methods inherited from class java.util.HashMap

clone, compute, computeIfAbsent, computeIfPresent, containsKey, isEmpty, merge, putAll, putIfAbsent, remove, replace, replace, size

Methods inherited from class java.util.AbstractMap

equals, hashCode, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Map

compute, computeIfAbsent, computeIfPresent, containsKey, equals, hashCode, isEmpty, merge, putAll, putIfAbsent, remove, replace, replace, size

Constructor Detail

ExpiringMap

public ExpiringMap(long timeout)

constructor

Parameters:

timeout -

ExpiringMap

public ExpiringMap(int initialCapacity,
                   float loadFactor,
                   boolean accessOrder,
                   long timeout)

constructor

Parameters:

initialCapacity -

loadFactor -

accessOrder -

ExpiringMap

public ExpiringMap(int initialCapacity,
                   float loadFactor,
                   long timeout)

constructor

Parameters:

initialCapacity -

loadFactor -

ExpiringMap

public ExpiringMap(int initialCapacity,
                   long timeout)

constructor

Parameters:

initialCapacity -

ExpiringMap

public ExpiringMap(Map<? extends K,? extends V> m,
                   long timeout)

constructor

Parameters:

m -

Method Detail

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>

remove

public V remove(Object key)

Specified by:

remove in interface Map<K,V>

Overrides:

remove in class HashMap<K,V>

clear

public void clear()

Specified by:

clear in interface Map<K,V>

Overrides:

clear in class LinkedHashMap<K,V>

shrink

protected void shrink()

does the thing and removes expired objects.

init

protected void init(long timeout)

creates the touch-time table

Parameters:

timeout - The timeout to set.