org.swat.cache.utils

Class ExpiryCache<K,V>

java.lang.Object

org.swat.cache.utils.ExpiryCache<K,V>

public class ExpiryCache<K,V>
extends Object

Very lazy expiry cache. Null key is not supported. It does not thrown any exception for null key. It is built on ConcurrentHashMap so is thread safe. It does not use any thread for removal of expired entries. Expired entries are removed when get(Object) or removeExpired() is called.

Author:

Swatantra Agrawal on 27-AUG-2017

Constructor Summary

Constructors

Constructor and Description
ExpiryCache(int expiryMillis) Initializes the cache

Method Summary

Modifier and Type	Method and Description
boolean	contains(K key) Contains
V	get(K key) Get value associated with the key
V	put(K key, V value) Put the value against the key.
V	put(K key, V value, int millis) Put the value against the key with defined expiry millis
void	removeExpired() Removes the expired objects
int	size() This may return an approximate size

Methods inherited from class java.lang.Object

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

Constructor Detail

ExpiryCache

public ExpiryCache(int expiryMillis)

Initializes the cache

Parameters:

expiryMillis - Expiry duration in millis

Method Detail

put

public V put(K key,
             V value)

Put the value against the key.

Parameters:

key - The key

value - The value

Returns:

Previous value. null if previous value is expired

put

public V put(K key,
             V value,
             int millis)

Put the value against the key with defined expiry millis

Parameters:

key - The key

value - The value

millis - The expiry duration in millis

Returns:

Previous value. null if previous value is expired

size

public int size()

This may return an approximate size

Returns:

The size of cache

removeExpired

public void removeExpired()

Removes the expired objects

get

public V get(K key)

Get value associated with the key

Parameters:

key - The key

Returns:

null if expired, else the value

contains

public boolean contains(K key)

Contains

Parameters:

key - the key

Returns:

true if the cache contains the key