fr.gouv.vitam.common.lru

Class SynchronizedLruCache<K,V>

java.lang.Object

fr.gouv.vitam.common.lru.SynchronizedLruCache<K,V>

Type Parameters:

K - Key

V - Value

All Implemented Interfaces:

InterfaceLruCache<K,V>

public class SynchronizedLruCache<K,V>
extends Object

Threadsafe synchronized implementation of LruCache based on LinkedHashMap. Threadsafety is provided by method synchronization. This cache implementation should be used with low number of threads. author Damian Momot

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_INITIAL_CAPACITY Initial capacity
static float	DEFAULT_LOAD_FACTOR Load factor

Constructor Summary

Constructors

Constructor and Description
SynchronizedLruCache(int capacity, long ttl) Creates new SynchronizedLruCache with DEFAULT_LOAD_FACTOR and DEFAULT_INITIAL_CAPACITY
SynchronizedLruCache(int capacity, long ttl, int initialCapacity) Creates new SynchronizedLruCache with DEFAULT_LOAD_FACTOR
SynchronizedLruCache(int capacity, long ttl, int initialCapacity, float loadFactor) Creates new SynchronizedLruCache

Method Summary

Modifier and Type	Method and Description
void	clear() Removes all entries from cache
boolean	contains(K key) Checks whether cache contains valid entry for key
protected InterfaceLruCacheEntry<V>	createEntry(V value, long ttl) Creates new LruCacheEntry.
int	forceClearOldest() Removes all oldest entries from cache (ttl based)
V	get(K key) Returns value cached with key.
V	get(K key, Callable<V> callback) Tries to get element from cache.
V	get(K key, Callable<V> callback, long ttl) Tries to get element from cache.
int	getCapacity() Returns cache capacity
protected InterfaceLruCacheEntry<V>	getEntry(K key) Returns LruCacheEntry mapped by key or null if it does not exist
long	getTtl() Returns cache TTL
protected V	getValue(K key) Tries to retrieve value by it's key.
boolean	isEmpty() Checks whether cache is empty.
void	put(K key, V value) Puts value under key into cache.
void	put(K key, V value, long ttl) Puts value under key into cache with desired TTL
protected void	putEntry(K key, InterfaceLruCacheEntry<V> entry) Puts entry into cache
V	remove(K key) Removes entry from cache (if exists)
void	setNewTtl(long ttl) Set a new TTL (for newly set objects only, not changing old values).
int	size() Returns number of entries stored in cache (including invalid ones)
void	updateTtl(K key) Update the TTL of the associated object if it still exists

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_INITIAL_CAPACITY

public static final int DEFAULT_INITIAL_CAPACITY

Initial capacity

See Also:

Constant Field Values

DEFAULT_LOAD_FACTOR

public static final float DEFAULT_LOAD_FACTOR

Load factor

See Also:

Constant Field Values

Constructor Detail

SynchronizedLruCache

public SynchronizedLruCache(int capacity,
                            long ttl,
                            int initialCapacity,
                            float loadFactor)

Creates new SynchronizedLruCache

Parameters:

capacity - max cache capacity

ttl - time to live in milliseconds

initialCapacity - initial cache capacity

loadFactor -

SynchronizedLruCache

public SynchronizedLruCache(int capacity,
                            long ttl,
                            int initialCapacity)

Creates new SynchronizedLruCache with DEFAULT_LOAD_FACTOR

Parameters:

capacity - max cache capacity

ttl - time to live in milliseconds

initialCapacity - initial cache capacity

SynchronizedLruCache

public SynchronizedLruCache(int capacity,
                            long ttl)

Creates new SynchronizedLruCache with DEFAULT_LOAD_FACTOR and DEFAULT_INITIAL_CAPACITY

Parameters:

capacity - max cache capacity

ttl - time to live in milliseconds

Method Detail

clear

public void clear()

Description copied from interface: InterfaceLruCache

Removes all entries from cache

get

public V get(K key)

Description copied from interface: InterfaceLruCache

Returns value cached with key.

Specified by:

get in interface InterfaceLruCache<K,V>

Returns:

value or null if key doesn't exist or entry is not valid

getCapacity

public int getCapacity()

Description copied from interface: InterfaceLruCache

Returns cache capacity

Returns:

capacity of cache

getEntry

protected InterfaceLruCacheEntry<V> getEntry(K key)

Returns LruCacheEntry mapped by key or null if it does not exist

Returns:

LruCacheEntry

size

public int size()

Description copied from interface: InterfaceLruCache

Returns number of entries stored in cache (including invalid ones)

Returns:

number of entries

put

public void put(K key,
                V value,
                long ttl)

Description copied from interface: InterfaceLruCache

Puts value under key into cache with desired TTL

Specified by:

put in interface InterfaceLruCache<K,V>

ttl - time to live in milliseconds

putEntry

protected void putEntry(K key,
                        InterfaceLruCacheEntry<V> entry)

Puts entry into cache

remove

public V remove(K key)

Description copied from interface: InterfaceLruCache

Removes entry from cache (if exists)

Returns:

the value if it still exists

forceClearOldest

public int forceClearOldest()

Description copied from interface: InterfaceLruCache

Removes all oldest entries from cache (ttl based)

Returns:

the number of removed entries

contains

public boolean contains(K key)

Description copied from interface: InterfaceLruCache

Checks whether cache contains valid entry for key

Specified by:

contains in interface InterfaceLruCache<K,V>

Returns:

true if cache contains key and entry is valid

createEntry

protected InterfaceLruCacheEntry<V> createEntry(V value,
                                                long ttl)

Creates new LruCacheEntry. It can be used to change implementation of LruCacheEntry

Parameters:

value -

ttl -

Returns:

LruCacheEntry

get

public V get(K key,
             Callable<V> callback)
      throws VitamException

Description copied from interface: InterfaceLruCache

Tries to get element from cache. If get fails callback is used to create element and returned value is stored in cache. Default TTL is used

Specified by:

get in interface InterfaceLruCache<K,V>

Returns:

Value

Throws:

VitamException

get

public V get(K key,
             Callable<V> callback,
             long ttl)
      throws VitamException

Description copied from interface: InterfaceLruCache

Tries to get element from cache. If get fails callback is used to create element and returned value is stored in cache

Specified by:

get in interface InterfaceLruCache<K,V>

ttl - time to live in milliseconds

Returns:

Value

Throws:

VitamException

getTtl

public long getTtl()

Description copied from interface: InterfaceLruCache

Returns cache TTL

Specified by:

getTtl in interface InterfaceLruCache<K,V>

Returns:

ttl in milliseconds

setNewTtl

public void setNewTtl(long ttl)

Description copied from interface: InterfaceLruCache

Set a new TTL (for newly set objects only, not changing old values).

Specified by:

setNewTtl in interface InterfaceLruCache<K,V>

updateTtl

public void updateTtl(K key)

Description copied from interface: InterfaceLruCache

Update the TTL of the associated object if it still exists

Specified by:

updateTtl in interface InterfaceLruCache<K,V>

getValue

protected V getValue(K key)

Tries to retrieve value by it's key. Automatically removes entry if it's not valid (LruCacheEntry.getValue() returns null)

Parameters:

key -

Returns:

Value

isEmpty

public boolean isEmpty()

Description copied from interface: InterfaceLruCache

Checks whether cache is empty. If any entry exists (including invalid one) this method will return true

Specified by:

isEmpty in interface InterfaceLruCache<K,V>

Returns:

true if no entries are stored in cache

put

public void put(K key,
                V value)

Description copied from interface: InterfaceLruCache

Puts value under key into cache. Default TTL is used

Specified by:

put in interface InterfaceLruCache<K,V>