org.waarp.common.lru

Interface InterfaceLruCache<K,V>

All Known Implementing Classes:

AbstractLruCache, SoftReferenceSynchronizedLruCache, SynchronizedLruCache

public interface InterfaceLruCache<K,V>

LRU cache interface.

Author:

Damian Momot

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
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
long	getTtl() Returns cache TTL
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
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

Method Detail

clear

void clear()

Removes all entries from cache

forceClearOldest

int forceClearOldest()

Removes all oldest entries from cache (ttl based)

Returns:

the number of removed entries

contains

boolean contains(K key)

Checks whether cache contains valid entry for key

Parameters:

key -

Returns:

true if cache contains key and entry is valid

get

V get(K key)

Returns value cached with key.

Parameters:

key -

Returns:

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

get

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

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

Parameters:

key -

callback -

Returns:

Value

Throws:

Exception - if callback throws exception

get

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

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

Parameters:

key -

callback -

ttl - time to live in milliseconds

Returns:

Value

Throws:

Exception - if callback throws exception

getCapacity

int getCapacity()

Returns cache capacity

Returns:

capacity of cache

size

int size()

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

Returns:

number of entries

getTtl

long getTtl()

Returns cache TTL

Returns:

ttl in milliseconds

setNewTtl

void setNewTtl(long ttl)

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

Parameters:

ttl -

isEmpty

boolean isEmpty()

Checks whether cache is empty.

If any entry exists (including invalid one) this method will return true

Returns:

true if no entries are stored in cache

put

void put(K key,
         V value)

Puts value under key into cache. Default TTL is used

Parameters:

key -

value -

put

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

Puts value under key into cache with desired TTL

Parameters:

key -

value -

ttl - time to live in milliseconds

remove

V remove(K key)

Removes entry from cache (if exists)

Parameters:

key -

Returns:

the value if it still exists

updateTtl

void updateTtl(K key)

Update the TTL of the associated object if it still exists

Parameters:

key -