DefaultLRUCachingMap (JHCaching 0.8 API)

java.lang.Object
- dk.heick.caching.DefaultLRUCachingMap<K,V>

Type Parameters:

K - the key

V - the value

All Implemented Interfaces:

LRUCachingMap<K,V>, Serializable

Direct Known Subclasses:

DefaultFileLRUCachingMap, DefaultFilenameFileReferenceLRUCachingMap, DefaultMemoryLRUCachingMap
```
public class DefaultLRUCachingMap<K,V>
extends Object
implements LRUCachingMap<K,V>, Serializable
```
Default implementation of LRUCachingMap, still using K,V as Key and Value.

Author:

Frederik Heick

See Also:

LRUCachingMap, Serialized Form

Constructor Summary

Constructors
Constructor and Description
`DefaultLRUCachingMap()` Default constructor, using `DefaultLRUCachingMapConfiguration` and `DefaultMemoryValueManager`.
`DefaultLRUCachingMap(LRUCachingMapConfiguration configuration, ValueManager<K,V> valueManager)` Constructor.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`int`	`cleanup()` Cleanup the cache to uphold expire time and maxSize. If maxSize is exceeded than the oldest must be remove until maxSize threshold is below limit. This method must call the value manager flush method when is done.
`boolean`	`exists(K key)` Validates if the key exists in the map, if its expired the key/value pair is removed.
`void`	`extend(K key)` Extends a key expire time with "getExtendTime()"
`void`	`extend(K key, long extendTime)` Extends a key expire time with an `extendTime` still, and the "getMaxExtendCount()" will have no effect.
`protected void`	`extend(K key, long extendTime, int maxExtendCount)`
`V`	`get(K key)` Gets a Value for a corresponding Key.
`LRUCachingMapConfiguration`	`getConfiguration()` Gets the configuration instance
`Date`	`getExpirationDateTime(K key)` When do the key expire.
`TimeSpan`	`getExpirationTimeSpan()` The timespan in milliseconds, between the oldest and youngest key
`TimeSpan`	`getExpirationTimeSpan(K key)` Gets the expiration timespan for a key.
`Iterator<K>`	`getKeys()` Get the keys in a iterator.
`Date`	`getLastCleanupDateTime()` Gets the last time the cleanup method was performed
`Logger`	`getLogger()` A logger for getting metrics on how the caching is performing.
`K`	`getNextToExpire()` Gets the next key which has the lowest expiration date time.
`Date`	`getStoreDateTime(K key)` When was the Key stored in the cache.
`ValueManager<K,V>`	`getValueManager()` The manager class which handles the wrapped values, so it either can be stored in memory, file, db, etc...
`protected AbstractValueWrapper<K,V>`	`getValueWrapper(K key)` Gets the "AbstractValueWrapper<K,V>" for the value.
`boolean`	`isExpired(K key)` Is the key is expired.
`boolean`	`isPersisted()` Determine if ValueManager persists the the values.
`V`	`peek(K key)` Peek at the value with the key, but it do not remove the key/value if it is expired or extend its expiration datetime.
`V`	`put(K key, V value)` Puts a key value pair in the cache.
`int`	`reload()` Will perform a complete reload of the cached elements if they are persisted, if not persisted nothing will happend.
`V`	`remove(K key)` Removes the key and its value form the cache.
`int`	`removeAll()` Remove all key/values from the cache, and delete the values if persisted.
`void`	`restoreCacheElement(K key, AbstractValueWrapper<K,V> valueWrapper, Date expireDateTime)` Used by `ValueManager.initialize(LRUCachingMap)` to initialize the caching structure, after an reload.
`int`	`size()` The number of unique keys in the cache.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - DefaultLRUCachingMap
```
public DefaultLRUCachingMap()
```
    Default constructor, using DefaultLRUCachingMapConfiguration and DefaultMemoryValueManager.
    
    See Also:
    
    DefaultLRUCachingMapConfiguration.DefaultLRUCachingMapConfiguration(), DefaultMemoryValueManager.DefaultMemoryValueManager(), DefaultLRUCachingMap(LRUCachingMapConfiguration, ValueManager)
  - DefaultLRUCachingMap
```
public DefaultLRUCachingMap(LRUCachingMapConfiguration configuration,
                            ValueManager<K,V> valueManager)
                     throws NullPointerException
```
    Constructor.
    
    If getConfiguration().getCleanupIntervalTime()>0 than an CleanupTimerRunnable will be created inside a thread to do periodically cleanup.
    And the thread is added to "Runtime.getRuntime().addShutdownHook(thread)" to secure termination of deamon thread.
    
    Parameters:
    
    configuration - the confiuration.
    
    valueManager - valueManager the instance of a ValueManager which handles how the values is stored.
    
    Throws:
    
    NullPointerException - if either configuration or valueManager is null.
    
    See Also:
    
    LRUCachingMapConfiguration.getCleanupIntervalTime(), CleanupTimerRunnable
- Method Detail
  - getConfiguration
```
public LRUCachingMapConfiguration getConfiguration()
```
    Description copied from interface: LRUCachingMap
    
    Gets the configuration instance
    
    Specified by:
    
    getConfiguration in interface LRUCachingMap<K,V>
    
    Returns:
    
    the instance of LRUCachingMapConfiguration.
    
    See Also:
    
    DefaultLRUCachingMapConfiguration
  - getLogger
```
public final Logger getLogger()
```
    Description copied from interface: LRUCachingMap
    
    A logger for getting metrics on how the caching is performing.
    
    Specified by:
    
    getLogger in interface LRUCachingMap<K,V>
    
    Returns:
    
    a logger instance.
  - getValueManager
```
public final ValueManager<K,V> getValueManager()
```
    Description copied from interface: LRUCachingMap
    
    The manager class which handles the wrapped values, so it either can be stored in memory, file, db, etc...
    
    Specified by:
    
    getValueManager in interface LRUCachingMap<K,V>
    
    Returns:
    
    the value manager instance.
  - size
```
public final int size()
```
    Description copied from interface: LRUCachingMap
    
    The number of unique keys in the cache.
    A cleanup is performed before size is returned.
    
    Specified by:
    
    size in interface LRUCachingMap<K,V>
    
    Returns:
    
    the number of unqiue keys in the cache.
  - removeAll
```
public final int removeAll()
```
    Description copied from interface: LRUCachingMap
    
    Remove all key/values from the cache, and delete the values if persisted.
    
    Specified by:
    
    removeAll in interface LRUCachingMap<K,V>
    
    Returns:
    
    the number of keys remove from the cache.
    
    See Also:
    
    LRUCachingMap.size()
  - reload
```
public final int reload()
```
    Description copied from interface: LRUCachingMap
    
    Will perform a complete reload of the cached elements if they are persisted, if not persisted nothing will happend.
    
    Specified by:
    
    reload in interface LRUCachingMap<K,V>
    
    Returns:
    
    the number of keys there is restored.
    
    See Also:
    
    LRUCachingMap.isPersisted()
  - put
```
public V put(K key,
             V value)
      throws NullPointerException
```
    Description copied from interface: LRUCachingMap
    
    Puts a key value pair in the cache.
    After a put method, and cleanup action is called, to ensure that maxSize limits is upholded.
    This should uphold the rules described for the class.
    This value store the value using the implementation in the ValueWrapper
    
    Specified by:
    
    put in interface LRUCachingMap<K,V>
    
    Parameters:
    
    key - the key
    
    value - the value if the value is null the key is removed.
    
    Returns:
    
    if a previous value was associated with the key, than this value is returned, otherwise null.
    
    Throws:
    
    NullPointerException - if the key is null.
    
    See Also:
    
    LRUCachingMapConfiguration.getExtendTime(), LRUCachingMapConfiguration.getMaxExtendCount(), LRUCachingMapConfiguration.getMaxSize(), ValueManager.storeValue(AbstractValueWrapper, Object, Object, Date), ValueManager.constructWrapper(Object, Object)
  - restoreCacheElement
```
public final void restoreCacheElement(K key,
                                      AbstractValueWrapper<K,V> valueWrapper,
                                      Date expireDateTime)
```
    Description copied from interface: LRUCachingMap
    
    Used by ValueManager.initialize(LRUCachingMap) to initialize the caching structure, after an reload.
    This is a backdoor to internal caching storing mechanism, without doing a complete "put" method.
    
    Specified by:
    
    restoreCacheElement in interface LRUCachingMap<K,V>
    
    Parameters:
    
    key - the reconstructed key
    
    valueWrapper - the value wrapped.
    
    expireDateTime - the datetime for when the key expires.
    
    See Also:
    
    ValueManager.restore(LRUCachingMap)
  - get
```
public final V get(K key)
            throws NullPointerException
```
    Description copied from interface: LRUCachingMap
    Gets a Value for a corresponding Key.
    With the rules.
    - If key is expired, the key/value is removed and null returned.
    - If key is not expired Extend the expire time according the rules described in the class and methods.
    Specified by:
    
    get in interface LRUCachingMap<K,V>
    
    Parameters:
    
    key - the key
    
    Returns:
    
    the value if any, otherwise null is returned.
    
    Throws:
    
    NullPointerException - if key is null.
    
    See Also:
    
    LRUCachingMapConfiguration
  - peek
```
public final V peek(K key)
             throws NullPointerException
```
    Description copied from interface: LRUCachingMap
    
    Peek at the value with the key, but it do not remove the key/value if it is expired or extend its expiration datetime.
    
    Specified by:
    
    peek in interface LRUCachingMap<K,V>
    
    Parameters:
    
    key - the key
    
    Returns:
    
    the value if any otherwise null.
    
    Throws:
    
    NullPointerException - if key is null.
  - isExpired
```
public final boolean isExpired(K key)
                        throws NullPointerException
```
    Description copied from interface: LRUCachingMap
    
    Is the key is expired.
    
    Specified by:
    
    isExpired in interface LRUCachingMap<K,V>
    
    Parameters:
    
    key - the key
    
    Returns:
    
    true if the key is expired or the key is not found, otherwise false.
    
    Throws:
    
    NullPointerException - if key is null.
  - getStoreDateTime
```
public final Date getStoreDateTime(K key)
                            throws NullPointerException
```
    Description copied from interface: LRUCachingMap
    
    When was the Key stored in the cache.
    
    Specified by:
    
    getStoreDateTime in interface LRUCachingMap<K,V>
    
    Parameters:
    
    key - the key
    
    Returns:
    
    if the key do not exists null is returned, otherwise the new Date(long) for when the key was registered in the cache.
    
    Throws:
    
    NullPointerException - if key is null.
  - remove
```
public final V remove(K key)
               throws NullPointerException
```
    Description copied from interface: LRUCachingMap
    
    Removes the key and its value form the cache.
    Calling the value valueWrapper.removeValue() method to clean up.
    
    Specified by:
    
    remove in interface LRUCachingMap<K,V>
    
    Parameters:
    
    key - the key
    
    Returns:
    
    the value that was stored.
    
    Throws:
    
    NullPointerException - if key is null.
    
    See Also:
    
    ValueManager.removeValue(AbstractValueWrapper)
  - exists
```
public final boolean exists(K key)
                     throws NullPointerException
```
    Description copied from interface: LRUCachingMap
    
    Validates if the key exists in the map, if its expired the key/value pair is removed.
    This DO NOT extend the keys expire time.
    
    Specified by:
    
    exists in interface LRUCachingMap<K,V>
    
    Parameters:
    
    key - the key
    
    Returns:
    
    true if key is exists and is not expired, otherwise false.
    
    Throws:
    
    NullPointerException - if key is null.
    
    See Also:
    
    LRUCachingMap.get(Object)
  - getKeys
```
public final Iterator<K> getKeys()
```
    Description copied from interface: LRUCachingMap
    
    Get the keys in a iterator.
    
    Specified by:
    
    getKeys in interface LRUCachingMap<K,V>
    
    Returns:
    
    all the keys as an Iterator.
    
    See Also:
    
    Iterator
  - extend
```
public void extend(K key,
                   long extendTime)
            throws NullPointerException,
                   IllegalArgumentException
```
    Description copied from interface: LRUCachingMap
    
    Extends a key expire time with an extendTime still, and the "getMaxExtendCount()" will have no effect.
    
    Specified by:
    
    extend in interface LRUCachingMap<K,V>
    
    Parameters:
    
    key - the key
    
    extendTime - how many milliseconds the keys expire time must be extended, must be greather than zero, otherwise nothing happens.
    
    Throws:
    
    NullPointerException - if key is null.
    
    IllegalArgumentException
    
    See Also:
    
    LRUCachingMapConfiguration.getMaxExtendCount()
  - extend
```
public void extend(K key)
            throws NullPointerException,
                   IllegalArgumentException
```
    Description copied from interface: LRUCachingMap
    
    Extends a key expire time with "getExtendTime()"
    
    Specified by:
    
    extend in interface LRUCachingMap<K,V>
    
    Parameters:
    
    key - the key
    
    Throws:
    
    NullPointerException - if key is null.
    
    IllegalArgumentException
    
    See Also:
    
    LRUCachingMapConfiguration.getMaxExtendCount(), LRUCachingMapConfiguration.getExtendTime()
  - extend
```
protected final void extend(K key,
                            long extendTime,
                            int maxExtendCount)
                     throws NullPointerException,
                            IllegalArgumentException
```
    Throws:
    
    NullPointerException
    
    IllegalArgumentException
  - getExpirationDateTime
```
public final Date getExpirationDateTime(K key)
                                 throws NullPointerException
```
    Description copied from interface: LRUCachingMap
    
    When do the key expire.
    
    Specified by:
    
    getExpirationDateTime in interface LRUCachingMap<K,V>
    
    Parameters:
    
    key - the key
    
    Returns:
    
    if the key was than the new Date(long) for the key expires, otherwise null.
    
    Throws:
    
    NullPointerException - if key is null.
  - getExpirationTimeSpan
```
public final TimeSpan getExpirationTimeSpan(K key)
                                     throws NullPointerException
```
    Description copied from interface: LRUCachingMap
    
    Gets the expiration timespan for a key.
    
    Specified by:
    
    getExpirationTimeSpan in interface LRUCachingMap<K,V>
    
    Parameters:
    
    key - the
    
    Returns:
    
    if key is found the returns the TimeSpan instance on how long the key has got in the cache, otherwise TimeSpan.ZERO is returned.
    
    Throws:
    
    NullPointerException - if key s null.
    
    See Also:
    
    TimeSpan.ZERO
  - cleanup
```
public final int cleanup()
```
    Description copied from interface: LRUCachingMap
    
    Cleanup the cache to uphold expire time and maxSize.
    If maxSize is exceeded than the oldest must be remove until maxSize threshold is below limit.
    This method must call the value manager flush method when is done.
    
    Specified by:
    
    cleanup in interface LRUCachingMap<K,V>
    
    Returns:
    
    the number of keys removed.
    
    See Also:
    
    LRUCachingMapConfiguration.getExpireTime(), LRUCachingMapConfiguration.getMaxSize(), LRUCachingMap.getNextToExpire(), ValueManager.flush(), LRUCachingMap.getValueManager()
  - getExpirationTimeSpan
```
public final TimeSpan getExpirationTimeSpan()
```
    Description copied from interface: LRUCachingMap
    
    The timespan in milliseconds, between the oldest and youngest key
    
    Specified by:
    
    getExpirationTimeSpan in interface LRUCachingMap<K,V>
    
    Returns:
    
    key timespan in milleseconds in a TimeSpan
  - getNextToExpire
```
public final K getNextToExpire()
```
    Description copied from interface: LRUCachingMap
    
    Gets the next key which has the lowest expiration date time.
    
    Specified by:
    
    getNextToExpire in interface LRUCachingMap<K,V>
    
    Returns:
    
    the next key with the lowest expiration date time, if none than null is returned.
  - isPersisted
```
public final boolean isPersisted()
```
    Description copied from interface: LRUCachingMap
    
    Determine if ValueManager persists the the values.
    
    Specified by:
    
    isPersisted in interface LRUCachingMap<K,V>
    
    Returns:
    
    true if value is stored in a persistence storage an can be recovered after "reboot", otherwise false.
    
    See Also:
    
    ValueManager.isPersisted()
  - getLastCleanupDateTime
```
public final Date getLastCleanupDateTime()
```
    Description copied from interface: LRUCachingMap
    
    Gets the last time the cleanup method was performed
    
    Specified by:
    
    getLastCleanupDateTime in interface LRUCachingMap<K,V>
    
    Returns:
    
    the last time the cleanup method was performed, if not performed yet it will return the date time for the instance construction time.
  - getValueWrapper
```
protected final AbstractValueWrapper<K,V> getValueWrapper(K key)
```
    Gets the "AbstractValueWrapper<K,V>" for the value.
    
    Parameters:
    
    key - the key
    
    Returns:
    
    the "AbstractValueWrapper<K,V>" instance.

Class DefaultLRUCachingMap<K,V>

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

DefaultLRUCachingMap

DefaultLRUCachingMap

Method Detail

getConfiguration

getLogger

getValueManager

size

removeAll

reload

put

restoreCacheElement

get

peek

isExpired

getStoreDateTime

remove

exists

getKeys

extend

extend

extend

getExpirationDateTime

getExpirationTimeSpan

cleanup

getExpirationTimeSpan

getNextToExpire

isPersisted

getLastCleanupDateTime

getValueWrapper