org.wandora.topicmap.database

Class WeakTopicIndex.CacheList<E>

java.lang.Object

org.wandora.topicmap.database.WeakTopicIndex.CacheList<E>

Enclosing class:

WeakTopicIndex

public static class WeakTopicIndex.CacheList<E>
extends java.lang.Object

Cache list is a list of objects where the most used objects are at the top of the list and least used objects are at the bottom. New objects are added somewhere in the middle but near the bottom. Objects are accessed which either moves them up in the list or adds them at the specified add point if they are not in the list allready.

The idea is that a limited number of objects from a very large object pool are kept in memeory and it is prefered that objects that are used the most stay in the list while objects that are used little fall off the list. Objects are not added right at the bottom to avoid them being falling off the list straight away and not having any chance of moving up.

List is implemented as a linked list with pointers to the top, bottom and the marked add position.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	WeakTopicIndex.CacheList.ListItem<E>

Field Summary

Fields

Modifier and Type	Field and Description
static int	cacheSize The maximum size of the list
private WeakTopicIndex.CacheList.ListItem<E>	first
private WeakTopicIndex.CacheList.ListItem<E>	last
private java.util.HashMap<E,WeakTopicIndex.CacheList.ListItem<E>>	map
private WeakTopicIndex.CacheList.ListItem<E>	mark
static int	markPos The position at which new objects are added
private int	size

Constructor Summary

Constructors

Constructor and Description
CacheList()

Method Summary

Modifier and Type	Method and Description
void	access(E e) Accesses an object moving it up in the list or adding it to the list if it isn't in it yet.
private void	addAtMark(E e)
private void	moveUp(WeakTopicIndex.CacheList.ListItem<E> item)
void	printDebugInfo()
int	size()

Methods inherited from class java.lang.Object

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

Field Detail

cacheSize

public static final int cacheSize

The maximum size of the list

See Also:

Constant Field Values

markPos

public static final int markPos

The position at which new objects are added

See Also:

Constant Field Values

size

private int size

last

private WeakTopicIndex.CacheList.ListItem<E> last

first

private WeakTopicIndex.CacheList.ListItem<E> first

mark

private WeakTopicIndex.CacheList.ListItem<E> mark

map

private java.util.HashMap<E,WeakTopicIndex.CacheList.ListItem<E>> map

Constructor Detail

CacheList

public CacheList()

Method Detail

addAtMark

private void addAtMark(E e)

moveUp

private void moveUp(WeakTopicIndex.CacheList.ListItem<E> item)

access

public void access(E e)

Accesses an object moving it up in the list or adding it to the list if it isn't in it yet.

size

public int size()

printDebugInfo

public void printDebugInfo()