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| Source file | Conditionals | Statements | Methods | TOTAL | |||||||||||||||
| FIFOCache.java | 75% | 77,8% | 83,3% | 78,6% |
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/*
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* Copyright (c) 2002-2003 by OpenSymphony
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* All rights reserved.
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*/
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package com.opensymphony.oscache.base.algorithm;
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import java.util.*;
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/**
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* FIFO (First In First Out) based queue algorithm for the cache.
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*
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* No synchronization is required in this class since the
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* <code>AbstractConcurrentReadCache</code> already takes care of any
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* synchronization requirements.
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*
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* @version $Revision: 1.1 $
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* @author <a href="mailto:mike@atlassian.com">Mike Cannon-Brookes</a>
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* @author <a href="mailto:abergevin@pyxis-tech.com">Alain Bergevin</a>
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* @author <a href="mailto:chris@swebtec.com">Chris Miller</a>
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*/
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public class FIFOCache extends AbstractConcurrentReadCache { |
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/**
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* A queue containing all cache keys
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*/
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private Collection list;
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/**
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* A flag indicating whether we are using a List or a Set for the key collection
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*/
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private boolean isSet = false; |
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/**
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* Constructs a FIFO Cache.
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*/
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public FIFOCache() {
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super();
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// Check if we're running under JRE 1.4+. If so we can use a LinkedHashSet
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// instead of a LinkedList for a big performance boost when removing elements.
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try {
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Class.forName("java.util.LinkedHashSet");
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list = new LinkedHashSet();
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isSet = true;
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} catch (ClassNotFoundException e) {
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list = new LinkedList();
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} |
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} |
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/**
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* Constructs a FIFO Cache of the specified capacity.
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*
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* @param capacity The maximum cache capacity.
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*/
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public FIFOCache(int capacity) { |
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this();
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maxEntries = capacity; |
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} |
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/**
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* An object was retrieved from the cache. This implementation
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* does noting since this event has no impact on the FIFO algorithm.
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*
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* @param key The cache key of the item that was retrieved.
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*/
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protected void itemRetrieved(Object key) { |
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} |
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/**
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* An object was put in the cache. This implementation just adds
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* the key to the end of the list if it doesn't exist in the list
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* already.
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*
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* @param key The cache key of the item that was put.
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*/
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protected void itemPut(Object key) { |
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if (!list.contains(key)) {
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list.add(key); |
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} |
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} |
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/**
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* An item needs to be removed from the cache. The FIFO implementation
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* removes the first element in the list (ie, the item that has been in
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* the cache for the longest time).
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*
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* @return The key of whichever item was removed.
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*/
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protected Object removeItem() {
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Object toRemove; |
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if (isSet) {
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Iterator it = list.iterator(); |
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toRemove = it.next(); |
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it.remove(); |
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} else {
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toRemove = ((List) list).remove(0); |
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} |
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return toRemove;
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} |
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/**
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* Remove specified key since that object has been removed from the cache.
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*
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* @param key The cache key of the item that was removed.
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*/
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protected void itemRemoved(Object key) { |
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list.remove(key); |
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} |
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} |
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