joshua.util.Cache< K, V > Class Reference

Inheritance diagram for joshua.util.Cache< K, V >:

Collaboration diagram for joshua.util.Cache< K, V >:

List of all members.

Public Member Functions
	Cache (int maxCapacity)
	Cache ()
V	get (Object key)
V	put (K key, V value)
boolean	containsKey (Object key)
Static Public Attributes
static final int	DEFAULT_CAPACITY = 100000000
static final int	INITIAL_CAPACITY = 1000000
static final float	LOAD_FACTOR = 0.75f
static final boolean	ACCESS_ORDER = true
Protected Member Functions
boolean	removeEldestEntry (Map.Entry< K, V > eldest)
Package Attributes
int	maxCapacity
Static Private Attributes
static final long	serialVersionUID = 6073387072740892061L
static Logger	logger = Logger.getLogger(Cache.class.getName())

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Detailed Description

Cache is a class that implements a least recently used cache. It is a straightforward extension of java.util.LinkedHashMap with its removeEldestEntry method overridden, so that stale entries are deleted once we reach the specified capacity of the Cache.

This class is quite useful for storing the results of computations that we would do many times over in the FeatureFunctions.

Author:

Chris Callison-Burch

Since:

14 April 2005

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Constructor & Destructor Documentation

joshua.util.Cache< K, V >.Cache

(

int

maxCapacity

)

Creates a Cache with a set capacity.

Parameters:

maxCapacity

the maximum capacity of the cache.

joshua.util.Cache< K, V >.Cache

(

)

Creates a Cache with the DEFAULT_CAPACITY.

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Member Function Documentation

boolean joshua.util.Cache< K, V >.containsKey

(

Object

key

)

V joshua.util.Cache< K, V >.get

(

Object

key

)

V joshua.util.Cache< K, V >.put	(	K	key,
		V	value
	)

boolean joshua.util.Cache< K, V >.removeEldestEntry

(

Map.Entry< K, V >

eldest

)

[protected]

This method is invoked by put and putAll after inserting a new entry into the map. Once we reach the capacity of the cache, we remove the oldest entry each time a new entry is added. This reduces memory consumption by deleting stale entries.

Parameters:

eldest

the eldest entry

Returns:

true if the capacity is greater than the maximum capacity

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Member Data Documentation

final boolean joshua.util.Cache< K, V >.ACCESS_ORDER = true [static]

By default, ordering mode of the cache is access order (true).

final int joshua.util.Cache< K, V >.DEFAULT_CAPACITY = 100000000 [static]

A constant is used as the default the cache size if none is specified.

final int joshua.util.Cache< K, V >.INITIAL_CAPACITY = 1000000 [static]

Default initial capacity of the cache.

final float joshua.util.Cache< K, V >.LOAD_FACTOR = 0.75f [static]

Default load factor of the cache.

Logger joshua.util.Cache< K, V >.logger = Logger.getLogger(Cache.class.getName()) [static, private]

Logger for this class.

int joshua.util.Cache< K, V >.maxCapacity [package]

Maximum number of items that the cache can contain.

final long joshua.util.Cache< K, V >.serialVersionUID = 6073387072740892061L [static, private]