| commit | author | age | ||
| 4d44cf | 1 | /* |
| JM | 2 | * Copyright 2011 gitblit.com. |
| 3 | * | |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); | |
| 5 | * you may not use this file except in compliance with the License. | |
| 6 | * You may obtain a copy of the License at | |
| 7 | * | |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 | |
| 9 | * | |
| 10 | * Unless required by applicable law or agreed to in writing, software | |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, | |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
| 13 | * See the License for the specific language governing permissions and | |
| 14 | * limitations under the License. | |
| 15 | */ | |
| 9275bd | 16 | package com.gitblit.utils; |
| 4d44cf | 17 | |
| JM | 18 | import java.io.Serializable; |
| 19 | import java.util.Date; | |
| 20 | import java.util.Map; | |
| 21 | import java.util.concurrent.ConcurrentHashMap; | |
| 22 | ||
| 23 | /** | |
| 9275bd | 24 | * Reusable coarse date-based object cache. The date precision is in |
| JM | 25 | * milliseconds and in fast, concurrent systems this cache is too simplistic. |
| 26 | * However, for the cases where its being used in Gitblit this cache technique | |
| 27 | * is just fine. | |
| 4d44cf | 28 | * |
| JM | 29 | * @author James Moger |
| 30 | * | |
| 31 | */ | |
| 32 | public class ObjectCache<X> implements Serializable { | |
| 33 | ||
| 34 | private static final long serialVersionUID = 1L; | |
| 35 | ||
| 36 | private final Map<String, CachedObject<X>> cache = new ConcurrentHashMap<String, CachedObject<X>>(); | |
| 37 | ||
| 38 | private class CachedObject<Y> { | |
| 39 | ||
| 40 | public final String name; | |
| 41 | ||
| 42 | private volatile Date date; | |
| 43 | ||
| 44 | private volatile Y object; | |
| 45 | ||
| 46 | CachedObject(String name) { | |
| 47 | this.name = name; | |
| 48 | date = new Date(0); | |
| 49 | } | |
| 50 | ||
| 51 | @Override | |
| 52 | public String toString() { | |
| 53 | return getClass().getSimpleName() + ": " + name; | |
| 54 | } | |
| 55 | } | |
| 56 | ||
| 57 | public boolean hasCurrent(String name, Date date) { | |
| 58 | return cache.containsKey(name) && cache.get(name).date.compareTo(date) == 0; | |
| 59 | } | |
| 60 | ||
| 61 | public Date getDate(String name) { | |
| 62 | return cache.get(name).date; | |
| 63 | } | |
| 64 | ||
| 65 | public X getObject(String name) { | |
| 9275bd | 66 | if (cache.containsKey(name)) { |
| JM | 67 | return cache.get(name).object; |
| 68 | } | |
| 69 | return null; | |
| 4d44cf | 70 | } |
| JM | 71 | |
| 72 | public void updateObject(String name, X object) { | |
| 73 | this.updateObject(name, new Date(), object); | |
| 74 | } | |
| 75 | ||
| 76 | public void updateObject(String name, Date date, X object) { | |
| 77 | CachedObject<X> obj; | |
| 78 | if (cache.containsKey(name)) { | |
| 79 | obj = cache.get(name); | |
| 80 | } else { | |
| 81 | obj = new CachedObject<X>(name); | |
| 82 | cache.put(name, obj); | |
| 83 | } | |
| 84 | obj.date = date; | |
| 85 | obj.object = object; | |
| 86 | } | |
| 87 | ||
| 88 | public Object remove(String name) { | |
| 4a2868 | 89 | if (cache.containsKey(name)) { |
| JM | 90 | return cache.remove(name).object; |
| 91 | } | |
| 92 | return null; | |
| 4d44cf | 93 | } |
| fee060 | 94 | |
| JM | 95 | public int size() { |
| 96 | return cache.size(); | |
| 97 | } | |
| 4d44cf | 98 | } |
