org.cdlib.xtf.util
Class FastIntCache

Object
  FastIntCache

public class FastIntCache
extends Object

A fast but inflexible cache where the keys are integers, the size is fixed, and a crude LRU policy is enforced. Handles consecutive keys gracefully. Doesn't support resizing, deletion, or iteration (not that these operations would be hard, just that they haven't been needed so far.)

Author:

Martin Haye

Field Summary

private IntHash	newHash
private IntHash	oldHash
private int	size
static Tester	tester Basic regression test

Constructor Summary

FastIntCache(int size)
Construct a new cache.

Method Summary

void	clear() Clears all entries from the cache
boolean	contains(int key) Check whether the given key is present in the cache
Object	get(int key) Retrieve the value for the given key, or null if not found.
void	put(int key, Object val) Add a key/value pair to the cache.

Methods inherited from class Object

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

Field Detail

size

private int size

oldHash

private IntHash oldHash

newHash

private IntHash newHash

tester

public static final Tester tester

Basic regression test

Constructor Detail

FastIntCache

public FastIntCache(int size)

Construct a new cache. Basically, two hash tables are used, each with the given capacity. When one fills up, the other is thrown out. A Least-Recently-Used policy is effected by migrating entries from the old hash to the new hash when they are accessed through get().

Parameters:

size - How large to make each of the two internal hash tables.

Method Detail

clear

public void clear()

Clears all entries from the cache

contains

public boolean contains(int key)

Check whether the given key is present in the cache

get

public Object get(int key)

Retrieve the value for the given key, or null if not found.

put

public void put(int key,
                Object val)

Add a key/value pair to the cache. May result in pushing older items out of the cache.