de.lmu.ifi.dbs.elki.persistent
Interface Cache<P extends Page<P>>

Type Parameters:

P - Page type

All Known Implementing Classes:

LRUCache

public interface Cache<P extends Page<P>>

Defines the requirements for a cache that stores objects implementing the Page interface.

Author:

Elke Achtert

Method Summary

void	clear() Clears this cache.
void	flush() Flushes this cache by writing any entry to the underlying file.
P	get(int id) Retrieves a page from this cache.
long	getPageAccess() Returns the number of page accesses.
void	initialize(long cacheSize, CachedFile<P> file) Initializes this cache with the specified parameters.
void	put(P object) Adds an object to this cache.
P	remove(int id) Removes an object from this cache.
void	resetPageAccess() Resets the pages access of this cache.
void	setCacheSize(int cacheSize) Sets the maximum size of this cache.

Method Detail

initialize

void initialize(long cacheSize,
                CachedFile<P> file)

Initializes this cache with the specified parameters.

Parameters:

cacheSize - the maximum number of pages in this cache

file - the underlying file of this cache, if a page is dropped it is written to the file

get

P get(int id)

Retrieves a page from this cache.

Parameters:

id - the id of the page to be returned.

Returns:

the page associated to the id or null if no value with this key exists in the cache.

put

void put(P object)

Adds an object to this cache.

Parameters:

object - the object to be added

remove

P remove(int id)

Removes an object from this cache.

Parameters:

id - the id of the object to be removed

Returns:

the removed object

flush

void flush()

Flushes this cache by writing any entry to the underlying file.

clear

void clear()

Clears this cache.

setCacheSize

void setCacheSize(int cacheSize)

Sets the maximum size of this cache.

Parameters:

cacheSize - the cache size to be set

getPageAccess

long getPageAccess()

Returns the number of page accesses.

Returns:

the number of page accesses

resetPageAccess

void resetPageAccess()

Resets the pages access of this cache.