groovyx.gpars.memoize
Class LRUProtectionStorage

java.lang.Object
  java.util.AbstractMap<K,V>
      java.util.HashMap<K,V>
          java.util.LinkedHashMap<java.lang.Object,java.lang.Object>
              groovyx.gpars.memoize.LRUProtectionStorage

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, java.util.Map<java.lang.Object,java.lang.Object>

public final class LRUProtectionStorage
extends java.util.LinkedHashMap<java.lang.Object,java.lang.Object>

Protects stored resources from eviction from memory following the LRU (Last Recently Used) strategy. If the maximum size has been reached all newly added elements will cause the oldest element to be removed from the storage in order not to exceed the maximum capacity. The touch method can be used to renew an element and move it to the from the LRU queue.

Author:

Vaclav Pech Date: Jun 22, 2010

See Also:

Serialized Form

Nested Class Summary

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

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

Field Summary

private int	maxSize
private static long	serialVersionUID

Constructor Summary

LRUProtectionStorage(int maxSize)

Method Summary

java.lang.Object	clone() Performs a shallow clone
java.lang.Object	get(java.lang.Object key)
protected boolean	removeEldestEntry(java.util.Map.Entry<java.lang.Object,java.lang.Object> eldest)
void	touch(java.lang.Object key, java.lang.Object value) The touch method can be used to renew an element and move it to the from of the LRU queue.

Methods inherited from class java.util.LinkedHashMap

clear, containsValue

Methods inherited from class java.util.HashMap

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

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

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

Field Detail

serialVersionUID

private static final long serialVersionUID

See Also:

Constant Field Values

maxSize

private final int maxSize

Constructor Detail

LRUProtectionStorage

public LRUProtectionStorage(int maxSize)

Method Detail

removeEldestEntry

protected boolean removeEldestEntry(java.util.Map.Entry<java.lang.Object,java.lang.Object> eldest)

Overrides:

removeEldestEntry in class java.util.LinkedHashMap<java.lang.Object,java.lang.Object>

touch

public void touch(java.lang.Object key,
                  java.lang.Object value)

The touch method can be used to renew an element and move it to the from of the LRU queue.

Parameters:

key - The key of the element to renew

value - A value to newly associate with the key

get

public java.lang.Object get(java.lang.Object key)

Specified by:

get in interface java.util.Map<java.lang.Object,java.lang.Object>

Overrides:

get in class java.util.LinkedHashMap<java.lang.Object,java.lang.Object>

clone

public java.lang.Object clone()

Performs a shallow clone

Overrides:

clone in class java.util.HashMap<java.lang.Object,java.lang.Object>

Returns:

The cloned instance