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| Source file | Conditionals | Statements | Methods | TOTAL | |||||||||||||||
| FIFOCache.java | 100% | 80% | 83,3% | 83,3% |
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| 1 | /* | |
| 2 | * Copyright (c) 2002-2003 by OpenSymphony | |
| 3 | * All rights reserved. | |
| 4 | */ | |
| 5 | package com.opensymphony.oscache.base.algorithm; | |
| 6 | ||
| 7 | import java.util.*; | |
| 8 | ||
| 9 | /** | |
| 10 | * FIFO (First In First Out) based queue algorithm for the cache. | |
| 11 | * | |
| 12 | * No synchronization is required in this class since the | |
| 13 | * <code>AbstractConcurrentReadCache</code> already takes care of any | |
| 14 | * synchronization requirements. | |
| 15 | * | |
| 16 | * @version $Revision: 427 $ | |
| 17 | * @author <a href="mailto:mike@atlassian.com">Mike Cannon-Brookes</a> | |
| 18 | * @author <a href="mailto:abergevin@pyxis-tech.com">Alain Bergevin</a> | |
| 19 | * @author <a href="mailto:chris@swebtec.com">Chris Miller</a> | |
| 20 | */ | |
| 21 | public class FIFOCache extends AbstractConcurrentReadCache { | |
| 22 | ||
| 23 | private static final long serialVersionUID = -10333778645392679L; | |
| 24 | ||
| 25 | /** | |
| 26 | * A queue containing all cache keys | |
| 27 | */ | |
| 28 | private Collection list = new LinkedHashSet(); | |
| 29 | ||
| 30 | /** | |
| 31 | * Constructs a FIFO Cache. | |
| 32 | */ | |
| 33 | 10 | public FIFOCache() { |
| 34 | 10 | super(); |
| 35 | } | |
| 36 | ||
| 37 | /** | |
| 38 | * Constructs a FIFO Cache of the specified capacity. | |
| 39 | * | |
| 40 | * @param capacity The maximum cache capacity. | |
| 41 | */ | |
| 42 | 0 | public FIFOCache(int capacity) { |
| 43 | 0 | this(); |
| 44 | 0 | maxEntries = capacity; |
| 45 | } | |
| 46 | ||
| 47 | /** | |
| 48 | * An object was retrieved from the cache. This implementation | |
| 49 | * does noting since this event has no impact on the FIFO algorithm. | |
| 50 | * | |
| 51 | * @param key The cache key of the item that was retrieved. | |
| 52 | */ | |
| 53 | 30 | protected void itemRetrieved(Object key) { |
| 54 | } | |
| 55 | ||
| 56 | /** | |
| 57 | * An object was put in the cache. This implementation just adds | |
| 58 | * the key to the end of the list if it doesn't exist in the list | |
| 59 | * already. | |
| 60 | * | |
| 61 | * @param key The cache key of the item that was put. | |
| 62 | */ | |
| 63 | 250 | protected void itemPut(Object key) { |
| 64 | 250 | if (!list.contains(key)) { |
| 65 | 240 | list.add(key); |
| 66 | } | |
| 67 | } | |
| 68 | ||
| 69 | /** | |
| 70 | * An item needs to be removed from the cache. The FIFO implementation | |
| 71 | * removes the first element in the list (ie, the item that has been in | |
| 72 | * the cache for the longest time). | |
| 73 | * | |
| 74 | * @return The key of whichever item was removed. | |
| 75 | */ | |
| 76 | 65 | protected Object removeItem() { |
| 77 | 65 | Iterator it = list.iterator(); |
| 78 | 65 | Object toRemove = it.next(); |
| 79 | 65 | it.remove(); |
| 80 | ||
| 81 | 65 | return toRemove; |
| 82 | } | |
| 83 | ||
| 84 | /** | |
| 85 | * Remove specified key since that object has been removed from the cache. | |
| 86 | * | |
| 87 | * @param key The cache key of the item that was removed. | |
| 88 | */ | |
| 89 | 165 | protected void itemRemoved(Object key) { |
| 90 | 165 | list.remove(key); |
| 91 | } | |
| 92 | } |
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