to.etc.util

Class LRUHashMap<K,V>

java.lang.Object

to.etc.util.LRUHashMap<K,V>

All Implemented Interfaces:

Map<K,V>

public class LRUHashMap<K,V>
extends Object
implements Map<K,V>

Hashmap which can use LRU removal of items.

Author:

Frits Jalvingh Created on Nov 25, 2010

Constructor Summary

Constructors

Constructor and Description
LRUHashMap(int maxsize)
LRUHashMap(int maxsize, int initial)

Method Summary

Modifier and Type	Method and Description
void	clear() Clear the map.
Object	clone() FIXME Needs an implementation
boolean	containsKey(Object key) Returns T if this map contains the keyed object.
boolean	containsValue(Object value) Returns T if this map contains the value.
Set<Map.Entry<K,V>>	entrySet() Returns a collection view of the mappings contained in this map.
V	get(Object key) Retrieve a value by key.
int	getMaxSize()
boolean	isEmpty()
Set<K>	keySet()
static void	main(String[] args)
V	put(K key, V value) Associates the specified value with the specified key in this map.
void	putAll(Map<? extends K,? extends V> m) Adds all of the elements to this map.
V	remove(Object key) Remove an entry by key.
int	size() Returns the current #elements in the map.
Collection<V>	values()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Map

compute, computeIfAbsent, computeIfPresent, equals, forEach, getOrDefault, hashCode, merge, putIfAbsent, remove, replace, replace, replaceAll

Constructor Detail

LRUHashMap

public LRUHashMap(int maxsize)

LRUHashMap

public LRUHashMap(int maxsize,
                  int initial)

Method Detail

size

public int size()

Returns the current #elements in the map.

Specified by:

size in interface Map<K,V>

getMaxSize

public int getMaxSize()

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Map<K,V>

clear

public void clear()

Clear the map.

Specified by:

clear in interface Map<K,V>

get

public V get(Object key)

Retrieve a value by key. If a value is found it gets moved to the most recently used position.

Specified by:

get in interface Map<K,V>

containsKey

public boolean containsKey(Object key)

Returns T if this map contains the keyed object. If the element is found it is not touched as used.

Specified by:

containsKey in interface Map<K,V>

put

public V put(K key,
             V value)

Associates the specified value with the specified key in this map. If the map previously contained a mapping for this key, the old value is replaced.

Specified by:

put in interface Map<K,V>

Parameters:

key - key with which the specified value is to be associated.

value - value to be associated with the specified key.

Returns:

previous value associated with specified key, or null if there was no mapping for key. A null return can also indicate that the HashMap previously associated null with the specified key.

putAll

public void putAll(Map<? extends K,? extends V> m)

Adds all of the elements to this map.

Specified by:

putAll in interface Map<K,V>

remove

public V remove(Object key)

Remove an entry by key.

Specified by:

remove in interface Map<K,V>

See Also:

Map.remove(java.lang.Object)

containsValue

public boolean containsValue(Object value)

Returns T if this map contains the value. This is EXPENSIVE as it needs to walk all of the objects in the map.

Specified by:

containsValue in interface Map<K,V>

See Also:

Map.containsValue(java.lang.Object)

clone

public Object clone()

FIXME Needs an implementation

Overrides:

clone in class Object

keySet

public Set<K> keySet()

Specified by:

keySet in interface Map<K,V>

values

public Collection<V> values()

Specified by:

values in interface Map<K,V>

entrySet

public Set<Map.Entry<K,V>> entrySet()

Returns a collection view of the mappings contained in this map. Each element in the returned collection is a Map.Entry. The collection is backed by the map, so changes to the map are reflected in the collection, and vice-versa. The collection supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Collection.remove, removeAll, retainAll, and clear operations. It does not support the add or addAll operations.

Specified by:

entrySet in interface Map<K,V>

Returns:

a collection view of the mappings contained in this map.

See Also:

Map.Entry

main

public static void main(String[] args)