com.hannesdorfmann.httpkit.cache

Class LruMemoryCache<K,V>

java.lang.Object

com.hannesdorfmann.httpkit.cache.LruMemoryCache<K,V>

All Implemented Interfaces:

MemoryCache<K,V>, SubCache<K,V>

Direct Known Subclasses:

BitmapLruMemoryCache, CastedBitmapLruMemoryCache

public abstract class LruMemoryCache<K,V>
extends Object
implements MemoryCache<K,V>

A LRU (Least recently used) memory cache

Author:

Hannes Dorfmann

Constructor Summary

Constructors

Constructor and Description
LruMemoryCache(int maxSize)

Method Summary

Methods

Modifier and Type	Method and Description
void	clear() Cleans the cache, by removing all cache entries
CacheEntry<V>	get(K key) Get the Cached entry
void	onLowMemory() This method is called, when the memory of the device runs low (RAM).
void	put(K key, CacheEntry<V> entry) Put a already existing entry in the memory cache
void	put(K key, V value, String mimeType, String charsetEncoding, long expirationTimeStamp, String eTag) Adds and create a new CacheEntry to the cache.
void	remove(K key) Removes the Entry
protected int	sizeOf(K key, CacheEntry<V> value) Returns the size of the entry for key and value in user-defined units.
void	updateExpirationTimestamp(K key, long expirationTimestamp) Will be called to update an expiration timestamp.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.hannesdorfmann.httpkit.cache.MemoryCache

isForType

Constructor Detail

LruMemoryCache

public LruMemoryCache(int maxSize)

Parameters:

maxSize - for caches that do not override sizeOf(K, com.hannesdorfmann.httpkit.cache.CacheEntry<V>), this is the maximum number of entries in the cache. For all other caches, this is the maximum sum of the sizes of the entries in this cache.

Method Detail

put

public void put(K key,
       V value,
       String mimeType,
       String charsetEncoding,
       long expirationTimeStamp,
       String eTag)

Adds and create a new CacheEntry to the cache.

Specified by:

put in interface MemoryCache<K,V>

Parameters:

key - The key

value - The Value for the given key

mimeType - The mime type of the value. This is important to find the correct parser for the stored cache value

charsetEncoding - The charset like, UTF-8 etc. that i used, to encode the string content (is useless for binary data)

expirationTimeStamp - The expiration value

eTag - The ETag

Throws:

Exception

put

public void put(K key,
       CacheEntry<V> entry)

Description copied from interface: MemoryCache

Put a already existing entry in the memory cache

Specified by:

put in interface MemoryCache<K,V>

get

public CacheEntry<V> get(K key)

Description copied from interface: MemoryCache

Get the Cached entry

Specified by:

get in interface MemoryCache<K,V>

Returns:

onLowMemory

public void onLowMemory()

Description copied from interface: MemoryCache

This method is called, when the memory of the device runs low (RAM).

Specified by:

onLowMemory in interface MemoryCache<K,V>

clear

public void clear()

Description copied from interface: MemoryCache

Cleans the cache, by removing all cache entries

Specified by:

clear in interface MemoryCache<K,V>

sizeOf

protected int sizeOf(K key,
         CacheEntry<V> value)

Returns the size of the entry for key and value in user-defined units. The default implementation returns 1 so that size is the number of entries and max size is the maximum number of entries.

An entry's size must not change while it is in the cache.

updateExpirationTimestamp

public void updateExpirationTimestamp(K key,
                             long expirationTimestamp)

Description copied from interface: SubCache

Will be called to update an expiration timestamp. Should not throw an exception, because we assume that expiration timestamp will always be extended to a date longer in the future. Therefore on failing the old expiration will not be renewed and the cache entry will expire. Hence in worst case retrieving the value from server will be needed. That's acceptable.

Specified by:

updateExpirationTimestamp in interface SubCache<K,V>

remove

public void remove(K key)
            throws IOException

Description copied from interface: SubCache

Removes the Entry

Specified by:

remove in interface SubCache<K,V>

Throws:

IOException