dk.heick.caching.persistences.file.reference

Class DefaultFilenameFileReferenceValueManager

java.lang.Object

dk.heick.caching.persistences.AbstractPersistenceValueManager<K,V>

dk.heick.caching.persistences.file.AbstractFileValueManager<String,File>

dk.heick.caching.persistences.file.reference.DefaultFilenameFileReferenceValueManager

All Implemented Interfaces:

ValueManager<String,File>

public final class DefaultFilenameFileReferenceValueManager
extends AbstractFileValueManager<String,File>

A ValueManager which holds file references.
Meaning that the key is a String which is stored in "file.getName()" and the value is File.
The ValueManager do NOT have the responsibility to save or retrieve the values containted in the files.
But will only hold the file reference.
But it WILL delete the files on restore PersistencesRestoreMethod.DELETE_ALL and PersistencesRestoreMethod.LOAD_WITHIN_EXPIRETIME, or when the key is expired or removed.

Author:

Frederik Heick

See Also:

File.getAbsolutePath()

Constructor Summary

Constructors

Constructor and Description
DefaultFilenameFileReferenceValueManager(CachingDirectory cachingDirectory, PersistencesRestoreMethod persistencesRestoreMethod) Constructor.

Method Summary

Modifier and Type	Method and Description
File	constructFile(String key, File value) Constructs a file using the Key and Value.
void	flush() This is ensures that any memory data that needs to be persisted is flushed.
String	reconstructKey(File file) When restoring a persisted LRUCachingMap, we need the ability to reconstruct the Key.
File	retrieveValue(AbstractValueWrapper<String,File> valueWrapper) Retrives value via the data contained in the ValueWrapper
void	storeValue(AbstractValueWrapper<String,File> valueWrapper, String key, File value, Date expireDateTime) Stores the value and giving the ValueWrapper enough information to retrieve/remove it again.

Methods inherited from class dk.heick.caching.persistences.file.AbstractFileValueManager

cast, constructWrapper, getCachingDirectory, getFile, removeAll, removeValue, restore, updateExpireTime

Methods inherited from class dk.heick.caching.persistences.AbstractPersistenceValueManager

getLogger, getPersistencesRestoreMethod, isPersisted

Methods inherited from class java.lang.Object

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

Constructor Detail

DefaultFilenameFileReferenceValueManager

public DefaultFilenameFileReferenceValueManager(CachingDirectory cachingDirectory,
                                                PersistencesRestoreMethod persistencesRestoreMethod)
                                         throws IllegalArgumentException,
                                                NullPointerException

Constructor.

Parameters:

cachingDirectory - the directory where to store the cached values.

persistencesRestoreMethod - the restore method, when reconstructing the LRUCachingMap.

Throws:

IllegalArgumentException - if cachingDirectory isnt a valid directory.

NullPointerException - if persistencesRestoreMethod or cachingDirectory is null.

Method Detail

storeValue

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

Description copied from interface: ValueManager

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

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.

retrieveValue

public File retrieveValue(AbstractValueWrapper<String,File> valueWrapper)
                   throws RuntimeException

Description copied from interface: ValueManager

Retrives value via the data contained in the ValueWrapper

Parameters:

valueWrapper - the

Returns:

the Value

Throws:

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

reconstructKey

public String reconstructKey(File file)

Description copied from class: AbstractFileValueManager

When restoring a persisted LRUCachingMap, we need the ability to reconstruct the Key.
Typical the filename is the key, otherwise it might be something in the value.
Must take the CachingDirectory into account and only use the path from the base caching directory and below:

Specified by:

reconstructKey in class AbstractFileValueManager<String,File>

Parameters:

file - the file.

Returns:

the key based on the file, if not able to reconstruct the key, the file is deleted.

constructFile

public File constructFile(String key,
                          File value)

Description copied from class: AbstractFileValueManager

Constructs a file using the Key and Value.

Specified by:

constructFile in class AbstractFileValueManager<String,File>

Parameters:

key - the key

value - the value

Returns:

a file

flush

public final 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.

See Also:

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