com.kheops.util

Class KDiskDataCache

java.lang.Object

com.kheops.util.KAbstractDataCache

com.kheops.util.KDiskDataCache

public class KDiskDataCache
extends KAbstractDataCache

A class used to store and retrieve data stored on disk.

Field Summary

Fields inherited from class com.kheops.util.KAbstractDataCache

currentSize, hits, maximumSize, misses

Constructor Summary

Constructors

Constructor and Description
KDiskDataCache(java.io.File path, long maxDiskCacheSize) Constructs a KDiskDataCache object working with the specified directory.

Method Summary

Modifier and Type	Method and Description
boolean	contains(java.lang.String key, long timeToLive) Tests for the existance of the data identified by the specified key.
void	export(KAbstractDataCache cache)
long	getCount()
long	getCount(java.lang.String partialKey) Returns the number of items present in the cache that have file names begining with the specified key.
long	getCurrentSize(java.lang.String partialKey) Gets the size in bytes of the data present in the cache that match the specified key.
long	getDataTime(java.lang.String key) Gets the last time the file was modified
KDataCacheMonitoringInfo	getMonitoringInfo(java.lang.String partialKey) Returns a KDataCacheMonitoringInfo object that defines monitoring information about this data cache.
long	getSize() Gets the total size in bytes of the data present in the cache
java.io.File[]	list() Returns the list of data files present in the cache.
java.io.File[]	listMatching(java.lang.String partialKey) Get the list of data files in the cache starting with the specified string.
static void	main(java.lang.String[] args) This method is used or test purposes
void	remove(java.lang.String key) Deletes the data corresponding to the specified key.
void	removeAll() Deletes all data stored in the cache.
void	removeMatching(java.lang.String partialKey) Deletes the data files with names that begin with the specified partial key.
byte[]	retrieve(java.lang.String key, long timeToLive) Retrieves the data previously stored using the specified key.
void	store(java.lang.String key, byte[] data) Stores the specified data using the specified key as the file name.

Methods inherited from class com.kheops.util.KAbstractDataCache

getCurrentSize, getHits, getMaximumSize, getMisses, getMonitoringInfo

Methods inherited from class java.lang.Object

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

Constructor Detail

KDiskDataCache

public KDiskDataCache(java.io.File path,
                      long maxDiskCacheSize)

Constructs a KDiskDataCache object working with the specified directory. If the directory does not exist, it is automatically created as well as all its parent directories, if necessary.

Parameters:

path - the base directory for storing data files

maxDiskCacheSize - the allowed size to be used as disk cache. -1 means unlimited.

Method Detail

store

public void store(java.lang.String key,
                  byte[] data)
           throws java.io.IOException

Stores the specified data using the specified key as the file name.

Specified by:

store in class KAbstractDataCache

Parameters:

key - the unique file name

data - the data to store on disk

Throws:

java.io.IOException

retrieve

public byte[] retrieve(java.lang.String key,
                       long timeToLive)
                throws java.io.IOException

Retrieves the data previously stored using the specified key. If the data does not exist the method returns null.

Parameters:

key - unique identifier used to search for the corresponding file name

timeToLive - amount of time used to determine the data has expired.

Returns:

the data retrieved from disk or null if it has expied or does not exist

Throws:

java.io.IOException

contains

public boolean contains(java.lang.String key,
                        long timeToLive)

Tests for the existance of the data identified by the specified key. The specified timeToLive determines if data is expired. If data was stored longer than timeToLive, it will be deleted and the method will return false.

Parameters:

key - the unique identifier for the data

timeToLive - time used to determine if the data has expired

Returns:

true if the data exists and has not expired, false otherwise

list

public java.io.File[] list()

Returns the list of data files present in the cache.

Returns:

an array containing files in the cache

listMatching

public java.io.File[] listMatching(java.lang.String partialKey)

Get the list of data files in the cache starting with the specified string.

Parameters:

partialKey - the begining of the file name.

Returns:

an array containing the matching files

remove

public void remove(java.lang.String key)

Deletes the data corresponding to the specified key. It does nothing if the data does not exist.

Parameters:

key - the unique identifier for the data

removeMatching

public void removeMatching(java.lang.String partialKey)

Deletes the data files with names that begin with the specified partial key.

Specified by:

removeMatching in class KAbstractDataCache

Parameters:

partialKey - the partial key to match

getDataTime

public long getDataTime(java.lang.String key)

Gets the last time the file was modified

Parameters:

key - the file name

Returns:

the corresponding time.

getSize

public long getSize()

Gets the total size in bytes of the data present in the cache

Returns:

the total size of the cache

removeAll

public void removeAll()

Deletes all data stored in the cache.

Specified by:

removeAll in class KAbstractDataCache

See Also:

KDiskDataCache

export

public void export(KAbstractDataCache cache)
            throws java.io.IOException

Specified by:

export in class KAbstractDataCache

Throws:

java.io.IOException

getCount

public long getCount()

Specified by:

getCount in class KAbstractDataCache

Returns:

the number of items present in the cache

getCount

public long getCount(java.lang.String partialKey)

Returns the number of items present in the cache that have file names begining with the specified key.

Specified by:

getCount in class KAbstractDataCache

Parameters:

partialKey - The file name to match

Returns:

the number of items matching the specified key.

getCurrentSize

public long getCurrentSize(java.lang.String partialKey)

Gets the size in bytes of the data present in the cache that match the specified key.

Specified by:

getCurrentSize in class KAbstractDataCache

Returns:

the size ofthe data matching the key

getMonitoringInfo

public KDataCacheMonitoringInfo getMonitoringInfo(java.lang.String partialKey)

Description copied from class: KAbstractDataCache

Returns a KDataCacheMonitoringInfo object that defines monitoring information about this data cache.

Overrides:

getMonitoringInfo in class KAbstractDataCache

Returns:

The monitoring info of the cache

main

public static void main(java.lang.String[] args)

This method is used or test purposes