1 /* GENERATED SOURCE. DO NOT MODIFY. */ 2 // © 2016 and later: Unicode, Inc. and others. 3 // License & terms of use: http://www.unicode.org/copyright.html#License 4 /* 5 ******************************************************************************* 6 * Copyright (C) 2009-2010, International Business Machines Corporation and * 7 * others. All Rights Reserved. * 8 ******************************************************************************* 9 */ 10 package ohos.global.icu.impl.locale; 11 12 import java.lang.ref.ReferenceQueue; 13 import java.lang.ref.SoftReference; 14 import java.util.concurrent.ConcurrentHashMap; 15 16 /** 17 * @hide exposed on OHOS 18 */ 19 public abstract class LocaleObjectCache<K, V> { 20 private ConcurrentHashMap<K, CacheEntry<K, V>> _map; 21 private ReferenceQueue<V> _queue = new ReferenceQueue<V>(); 22 LocaleObjectCache()23 public LocaleObjectCache() { 24 this(16, 0.75f, 16); 25 } 26 LocaleObjectCache(int initialCapacity, float loadFactor, int concurrencyLevel)27 public LocaleObjectCache(int initialCapacity, float loadFactor, int concurrencyLevel) { 28 _map = new ConcurrentHashMap<K, CacheEntry<K, V>>(initialCapacity, loadFactor, concurrencyLevel); 29 } 30 get(K key)31 public V get(K key) { 32 V value = null; 33 34 cleanStaleEntries(); 35 CacheEntry<K, V> entry = _map.get(key); 36 if (entry != null) { 37 value = entry.get(); 38 } 39 if (value == null) { 40 key = normalizeKey(key); 41 V newVal = createObject(key); 42 if (key == null || newVal == null) { 43 // subclass must return non-null key/value object 44 return null; 45 } 46 47 CacheEntry<K, V> newEntry = new CacheEntry<K, V>(key, newVal, _queue); 48 49 while (value == null) { 50 cleanStaleEntries(); 51 entry = _map.putIfAbsent(key, newEntry); 52 if (entry == null) { 53 value = newVal; 54 break; 55 } else { 56 value = entry.get(); 57 } 58 } 59 } 60 return value; 61 } 62 63 @SuppressWarnings("unchecked") cleanStaleEntries()64 private void cleanStaleEntries() { 65 CacheEntry<K, V> entry; 66 while ((entry = (CacheEntry<K, V>)_queue.poll()) != null) { 67 _map.remove(entry.getKey()); 68 } 69 } 70 createObject(K key)71 protected abstract V createObject(K key); 72 normalizeKey(K key)73 protected K normalizeKey(K key) { 74 return key; 75 } 76 77 private static class CacheEntry<K, V> extends SoftReference<V> { 78 private K _key; 79 CacheEntry(K key, V value, ReferenceQueue<V> queue)80 CacheEntry(K key, V value, ReferenceQueue<V> queue) { 81 super(value, queue); 82 _key = key; 83 } 84 getKey()85 K getKey() { 86 return _key; 87 } 88 } 89 } 90