de.greenrobot.common

Class ObjectCache<KEY,VALUE>

java.lang.Object

de.greenrobot.common.ObjectCache<KEY,VALUE>

public class ObjectCache<KEY,VALUE>
extends Object

An in-memory object cache supporting soft/weak/strong references, maximum size (clearing the entries putted first), and time-based expiration.

Author:

markus

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ObjectCache.ReferenceType

Constructor Summary

Constructors

Constructor and Description
ObjectCache(ObjectCache.ReferenceType referenceType, int maxSize, long expirationMillis) Create a cache according to the given configuration.

Method Summary

Methods

Modifier and Type	Method and Description
int	cleanUpObsoleteEntries() Iterates over all entries to check for obsolete ones (time expired or reference cleared).
void	clear() Clears all cached entries.
boolean	containsKey(KEY key)
boolean	containsKeyWithValue(KEY key)
void	evictToTargetSize(int targetSize)
VALUE	get(KEY key) Get the cached entry or null if no valid cached entry is found.
int	getCountEvicted()
int	getCountExpired()
int	getCountHit()
int	getCountMiss()
int	getCountPut()
int	getCountRefCleared()
int	getMaxSize()
String	getStatsStringRemoved() Often used in addition to toString() to print out states: details why entries were removed.
Set<KEY>	keySet()
VALUE	put(KEY key, VALUE object) Stores an new entry in the cache.
void	putAll(Map<KEY,VALUE> mapDataToPut) Stores all entries contained in the given map in the cache.
VALUE	remove(KEY key) Removes an entry from the cache.
int	size()
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

ObjectCache

public ObjectCache(ObjectCache.ReferenceType referenceType,
           int maxSize,
           long expirationMillis)

Create a cache according to the given configuration.

Parameters:

referenceType - SOFT is usually a good choice allowing the VM to clear caches when running low on memory. STRONG may also be preferred, e.g. when the required space is granted.

maxSize - The maximum number of entries stored by this cache

expirationMillis -

Method Detail

put

public VALUE put(KEY key,
        VALUE object)

Stores an new entry in the cache.

putAll

public void putAll(Map<KEY,VALUE> mapDataToPut)

Stores all entries contained in the given map in the cache.

get

public VALUE get(KEY key)

Get the cached entry or null if no valid cached entry is found.

clear

public void clear()

Clears all cached entries.

remove

public VALUE remove(KEY key)

Removes an entry from the cache.

Returns:

The removed entry

evictToTargetSize

public void evictToTargetSize(int targetSize)

cleanUpObsoleteEntries

public int cleanUpObsoleteEntries()

Iterates over all entries to check for obsolete ones (time expired or reference cleared).

Note: Usually you don't need to call this method explicitly, because it is called internally in certain conditions when space has to be reclaimed.

containsKey

public boolean containsKey(KEY key)

containsKeyWithValue

public boolean containsKeyWithValue(KEY key)

keySet

public Set<KEY> keySet()

getMaxSize

public int getMaxSize()

size

public int size()

getCountPut

public int getCountPut()

getCountHit

public int getCountHit()

getCountMiss

public int getCountMiss()

getCountExpired

public int getCountExpired()

getCountRefCleared

public int getCountRefCleared()

getCountEvicted

public int getCountEvicted()

toString

public String toString()

Overrides:

toString in class Object

getStatsStringRemoved

public String getStatsStringRemoved()

Often used in addition to toString() to print out states: details why entries were removed.