edu.internet2.middleware.grouperInstaller.util

Class ExpirableCache<K,V>

java.lang.Object

edu.internet2.middleware.grouperInstaller.util.ExpirableCache<K,V>

Type Parameters:

K - key type

V - value type

All Implemented Interfaces:

Serializable

public class ExpirableCache<K,V>
extends Object
implements Serializable

This is like a map, but the setters also take an expire time which will mean the items in the cache will be automatically deleted. Also, every so often (e.g. 2 minutes) all items are checked for expiration. If no timetolive is set, it will default to 1 day. The max time to live is one day. This is synchronized so that all access is safe.

Note, evictions are check for periodically, but only when the map is accessed (and even then only every few minutes). so you can check for evictions externally, or clear the map if you are done with it.

Version:

$Id: ExpirableCache.java,v 1.1 2008-11-27 14:25:50 mchyzer Exp $

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
ExpirableCache()
ExpirableCache(int defaultTimeToLiveInMinutes)

Method Summary

Modifier and Type	Method and Description
void	checkForEvictions(boolean onlyCheckIfNeeded) check and remove elements that are stale
void	clear() delete the cache
static void	clearAll() clear out all caches everywhere (session, request, context, etc)
V	get(K key) get a value or null if not there or expired this will check for eviction, and evict if evictable
int	getCacheEvictions() number of items evicted from cache
int	getCacheHits() number of items successfully retrieved from cache
int	getCacheInserts() number of items inserted into the cache
void	put(K key, V value) put a value into the cache, accept the default time to live for this cache
void	put(K key, V value, int timeToLiveInMinutes) put a value into the cache, accept the default time to live for this cache
int	size(boolean evictEvictables) number of elements in map (and check for
static String	staticToString() string representation of cache
String	toString() string representation of cache

Methods inherited from class java.lang.Object

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

Constructor Detail

ExpirableCache

public ExpirableCache()

ExpirableCache

public ExpirableCache(int defaultTimeToLiveInMinutes)

Parameters:

defaultTimeToLiveInMinutes - time in minutes is the default cache time to live for content

Method Detail

clear

public void clear()

delete the cache

put

public void put(K key,
                V value)

put a value into the cache, accept the default time to live for this cache

Parameters:

key -

value -

put

public void put(K key,
                V value,
                int timeToLiveInMinutes)

put a value into the cache, accept the default time to live for this cache

Parameters:

key -

value -

timeToLiveInMinutes - time to live for this item in minutes. If -1 then use the default

clearAll

public static void clearAll()

clear out all caches everywhere (session, request, context, etc)

checkForEvictions

public void checkForEvictions(boolean onlyCheckIfNeeded)

check and remove elements that are stale

Parameters:

onlyCheckIfNeeded - true if only check every so often (e.g. every two minutes)

get

public V get(K key)

get a value or null if not there or expired this will check for eviction, and evict if evictable

Parameters:

key -

Returns:

the value or null if not there or evicted

size

public int size(boolean evictEvictables)

number of elements in map (and check for

Parameters:

evictEvictables - true if we should evict values that are stale (even if recently checked)

Returns:

the number of elements

getCacheInserts

public int getCacheInserts()

number of items inserted into the cache

Returns:

Returns the cacheInserts.

getCacheEvictions

public int getCacheEvictions()

number of items evicted from cache

Returns:

Returns the cacheEvictions.

getCacheHits

public int getCacheHits()

number of items successfully retrieved from cache

Returns:

Returns the cacheHits.

toString

public String toString()

string representation of cache

Overrides:

toString in class Object

See Also:

Object.toString()

staticToString

public static String staticToString()

string representation of cache

Returns:

the string value