dk.heick.caching.memory

Class DefaultMemoryValueManager<K,V>

java.lang.Object

dk.heick.caching.memory.DefaultMemoryValueManager<K,V>

Type Parameters:

K - the key type.

V - the value type.

All Implemented Interfaces:

ValueManager<K,V>

public class DefaultMemoryValueManager<K,V>
extends Object
implements ValueManager<K,V>

A ValueManager which holds values in memory.

Author:

Frederik Heick

Constructor Summary

Constructors

Constructor and Description
DefaultMemoryValueManager() Constructor

Method Summary

Modifier and Type	Method and Description
AbstractValueWrapper<K,V>	constructWrapper(K key, V value) Construct a ValueWrapper for the value, but do not sets the value, this is done either in "restore" or "storeValue"
void	flush() This is ensures that any memory data that needs to be persisted is flushed.
Logger	getLogger() A logger for getting metrics on how the caching is performing.
boolean	isPersisted() Determine if the values is in a persistence storage.
int	removeAll() Remove all persisted values from the value "storage".
void	removeValue(AbstractValueWrapper<K,V> valueWrapper) Removes the value
void	restore(LRUCachingMap<K,V> map) Restores any persisted key/values to the LRUCachingMap when the map is constructed.
V	retrieveValue(AbstractValueWrapper<K,V> valueWrapper) Retrives value via the data contained in the ValueWrapper
void	storeValue(AbstractValueWrapper<K,V> valueWrapper, K key, V value, Date expireDateTime) Stores the value and giving the ValueWrapper enough information to retrieve/remove it again.
void	updateExpireTime(AbstractValueWrapper<K,V> valueWrapper, Date expireDateTime) Update the expiration date time for a value.

Methods inherited from class java.lang.Object

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

Constructor Detail

DefaultMemoryValueManager

public DefaultMemoryValueManager()

Constructor

Method Detail

restore

public final void restore(LRUCachingMap<K,V> map)

Description copied from interface: ValueManager

Restores any persisted key/values to the LRUCachingMap when the map is constructed.
This is used if your values is stored in a persistence storage like a file etc.
This method should find all persistence instances and reinitialize the "map" using the method "restoreCacheElement(K,AbstractValueWrapper<K,V>,Date)".
This method must call the "flush" method when done.

Specified by:

restore in interface ValueManager<K,V>

Parameters:

map - the map instance.

See Also:

LRUCachingMap.restoreCacheElement(Object, AbstractValueWrapper, Date), PersistencesRestoreMethod, AbstractPersistenceValueManager, ValueManager.flush()

isPersisted

public final boolean isPersisted()

Description copied from interface: ValueManager

Determine if the values is in a persistence storage.

Specified by:

isPersisted in interface ValueManager<K,V>

Returns:

true if value is stored in a persistence storage an can be recovered after "reboot", otherwise false.

constructWrapper

public AbstractValueWrapper<K,V> constructWrapper(K key,
                                                  V value)

Description copied from interface: ValueManager

Construct a ValueWrapper for the value, but do not sets the value, this is done either in "restore" or "storeValue"

Specified by:

constructWrapper in interface ValueManager<K,V>

Parameters:

key - the key

value - the value

Returns:

a ValueWrapper instance.

See Also:

ValueManager.restore(LRUCachingMap), ValueManager.storeValue(AbstractValueWrapper, Object, Object, Date)

storeValue

public void storeValue(AbstractValueWrapper<K,V> valueWrapper,
                       K key,
                       V value,
                       Date expireDateTime)
                throws RuntimeException

Description copied from interface: ValueManager

Stores the value and giving the ValueWrapper enough information to retrieve/remove it again.

Specified by:

storeValue in interface ValueManager<K,V>

Parameters:

valueWrapper - the wrapper instance to store the value or information about the value, this can be used to minimize the memory footprint.

key - the key

value - the value

expireDateTime - the expiration datetime for the key, this can be stored on a persisted key/value and used in case of a restore.

Throws:

RuntimeException - if for any reason the value could not be store.

removeValue

public void removeValue(AbstractValueWrapper<K,V> valueWrapper)
                 throws RuntimeException

Description copied from interface: ValueManager

Removes the value

Specified by:

removeValue in interface ValueManager<K,V>

Throws:

RuntimeException - if for any reason the value could not be removed.

retrieveValue

public V retrieveValue(AbstractValueWrapper<K,V> valueWrapper)
                throws RuntimeException

Description copied from interface: ValueManager

Retrives value via the data contained in the ValueWrapper

Specified by:

retrieveValue in interface ValueManager<K,V>

Parameters:

valueWrapper - the

Returns:

the Value

Throws:

RuntimeException - if for any reason the value could not be retrieved.

updateExpireTime

public void updateExpireTime(AbstractValueWrapper<K,V> valueWrapper,
                             Date expireDateTime)
                      throws RuntimeException

Description copied from interface: ValueManager

Update the expiration date time for a value.

Specified by:

updateExpireTime in interface ValueManager<K,V>

Parameters:

valueWrapper - the wrapper which holds enough information to get the value.

expireDateTime - the new expireDateTime

Throws:

RuntimeException - if this for any reasons fails.

removeAll

public final int removeAll()

Description copied from interface: ValueManager

Remove all persisted values from the value "storage".

Specified by:

removeAll in interface ValueManager<K,V>

Returns:

the number of values is removed.

flush

public void flush()

This is ensures that any memory data that needs to be persisted is flushed.
This is the case with Indexed value managers.
This method must be called by the LRUCachingMap implementation after "cleanup" and after "restore". Does nothing.

Specified by:

flush in interface ValueManager<K,V>

See Also:

LRUCachingMap.cleanup(), ValueManager.restore(LRUCachingMap)

getLogger

public Logger getLogger()

Description copied from interface: ValueManager

A logger for getting metrics on how the caching is performing.

Specified by:

getLogger in interface ValueManager<K,V>

Returns:

a logger instance.