Showing the changes to java/pkg/sun/util/locale/LocaleObjectCache.java (1 of 18352 files). Show all
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| 1 | +/* | |
| 2 | + * Copyright (c) 2010, 2011, Oracle and/or its affiliates. All rights reserved. | |
| 3 | + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
| 4 | + * | |
| 5 | + * This code is free software; you can redistribute it and/or modify it | |
| 6 | + * under the terms of the GNU General Public License version 2 only, as | |
| 7 | + * published by the Free Software Foundation. Oracle designates this | |
| 8 | + * particular file as subject to the "Classpath" exception as provided | |
| 9 | + * by Oracle in the LICENSE file that accompanied this code. | |
| 10 | + * | |
| 11 | + * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 12 | + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 13 | + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 14 | + * version 2 for more details (a copy is included in the LICENSE file that | |
| 15 | + * accompanied this code). | |
| 16 | + * | |
| 17 | + * You should have received a copy of the GNU General Public License version | |
| 18 | + * 2 along with this work; if not, write to the Free Software Foundation, | |
| 19 | + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 20 | + * | |
| 21 | + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
| 22 | + * or visit www.oracle.com if you need additional information or have any | |
| 23 | + * questions. | |
| 24 | + */ | |
| 25 | + | |
| 26 | +/* | |
| 27 | + ******************************************************************************* | |
| 28 | + * Copyright (C) 2009-2010, International Business Machines Corporation and * | |
| 29 | + * others. All Rights Reserved. * | |
| 30 | + ******************************************************************************* | |
| 31 | + */ | |
| 32 | +package sun.util.locale; | |
| 33 | + | |
| 34 | +import java.lang.ref.ReferenceQueue; | |
| 35 | +import java.lang.ref.SoftReference; | |
| 36 | +import java.util.concurrent.ConcurrentHashMap; | |
| 37 | +import java.util.concurrent.ConcurrentMap; | |
| 38 | + | |
| 39 | +public abstract class LocaleObjectCache<K, V> { | |
| 40 | + private ConcurrentMap<K, CacheEntry<K, V>> map; | |
| 41 | + private ReferenceQueue<V> queue = new ReferenceQueue<>(); | |
| 42 | + | |
| 43 | + public LocaleObjectCache() { | |
| 44 | + this(16, 0.75f, 16); | |
| 45 | + } | |
| 46 | + | |
| 47 | + public LocaleObjectCache(int initialCapacity, float loadFactor, int concurrencyLevel) { | |
| 48 | + map = new ConcurrentHashMap<>(initialCapacity, loadFactor, concurrencyLevel); | |
| 49 | + } | |
| 50 | + | |
| 51 | + public V get(K key) { | |
| 52 | + V value = null; | |
| 53 | + | |
| 54 | + cleanStaleEntries(); | |
| 55 | + CacheEntry<K, V> entry = map.get(key); | |
| 56 | + if (entry != null) { | |
| 57 | + value = entry.get(); | |
| 58 | + } | |
| 59 | + if (value == null) { | |
| 60 | + key = normalizeKey(key); | |
| 61 | + V newVal = createObject(key); | |
| 62 | + if (key == null || newVal == null) { | |
| 63 | + // subclass must return non-null key/value object | |
| 64 | + return null; | |
| 65 | + } | |
| 66 | + | |
| 67 | + CacheEntry<K, V> newEntry = new CacheEntry<>(key, newVal, queue); | |
| 68 | + | |
| 69 | + while (value == null) { | |
| 70 | + cleanStaleEntries(); | |
| 71 | + entry = map.putIfAbsent(key, newEntry); | |
| 72 | + if (entry == null) { | |
| 73 | + value = newVal; | |
| 74 | + break; | |
| 75 | + } else { | |
| 76 | + value = entry.get(); | |
| 77 | + } | |
| 78 | + } | |
| 79 | + } | |
| 80 | + return value; | |
| 81 | + } | |
| 82 | + | |
| 83 | + protected V put(K key, V value) { | |
| 84 | + CacheEntry<K, V> entry = new CacheEntry<>(key, value, queue); | |
| 85 | + CacheEntry<K, V> oldEntry = map.put(key, entry); | |
| 86 | + return (oldEntry == null) ? null : oldEntry.get(); | |
| 87 | + } | |
| 88 | + | |
| 89 | + @SuppressWarnings("unchecked") | |
| 90 | + private void cleanStaleEntries() { | |
| 91 | + CacheEntry<K, V> entry; | |
| 92 | + while ((entry = (CacheEntry<K, V>)queue.poll()) != null) { | |
| 93 | + map.remove(entry.getKey()); | |
| 94 | + } | |
| 95 | + } | |
| 96 | + | |
| 97 | + protected abstract V createObject(K key); | |
| 98 | + | |
| 99 | + protected K normalizeKey(K key) { | |
| 100 | + return key; | |
| 101 | + } | |
| 102 | + | |
| 103 | + private static class CacheEntry<K, V> extends SoftReference<V> { | |
| 104 | + private K key; | |
| 105 | + | |
| 106 | + CacheEntry(K key, V value, ReferenceQueue<V> queue) { | |
| 107 | + super(value, queue); | |
| 108 | + this.key = key; | |
| 109 | + } | |
| 110 | + | |
| 111 | + K getKey() { | |
| 112 | + return key; | |
| 113 | + } | |
| 114 | + } | |
| 115 | +} | |