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      1 //  2016 and later: Unicode, Inc. and others.
      2 // License & terms of use: http://www.unicode.org/copyright.html#License
      3 /*
      4  ****************************************************************************
      5  * Copyright (c) 2007-2011 International Business Machines Corporation and  *
      6  * others.  All rights reserved.                                            *
      7  ****************************************************************************
      8  */
      9 
     10 package com.ibm.icu.impl;
     11 
     12 import java.lang.ref.Reference;
     13 import java.lang.ref.SoftReference;
     14 import java.lang.ref.WeakReference;
     15 import java.util.Collections;
     16 import java.util.HashMap;
     17 import java.util.Map;
     18 
     19 public class SimpleCache<K, V> implements ICUCache<K, V> {
     20     private static final int DEFAULT_CAPACITY = 16;
     21 
     22     private Reference<Map<K, V>> cacheRef = null;
     23     private int type = ICUCache.SOFT;
     24     private int capacity = DEFAULT_CAPACITY;
     25 
     26     public SimpleCache() {
     27     }
     28 
     29     public SimpleCache(int cacheType) {
     30         this(cacheType, DEFAULT_CAPACITY);
     31     }
     32 
     33     public SimpleCache(int cacheType, int initialCapacity) {
     34         if (cacheType == ICUCache.WEAK) {
     35             type = cacheType;
     36         }
     37         if (initialCapacity > 0) {
     38             capacity = initialCapacity;
     39         }
     40     }
     41 
     42     public V get(Object key) {
     43         Reference<Map<K, V>> ref = cacheRef;
     44         if (ref != null) {
     45             Map<K, V> map = ref.get();
     46             if (map != null) {
     47                 return map.get(key);
     48             }
     49         }
     50         return null;
     51     }
     52 
     53     public void put(K key, V value) {
     54         Reference<Map<K, V>> ref = cacheRef;
     55         Map<K, V> map = null;
     56         if (ref != null) {
     57             map = ref.get();
     58         }
     59         if (map == null) {
     60             map = Collections.synchronizedMap(new HashMap<K, V>(capacity));
     61             if (type == ICUCache.WEAK) {
     62                 ref = new WeakReference<Map<K, V>>(map);
     63             } else {
     64                 ref = new SoftReference<Map<K, V>>(map);
     65             }
     66             cacheRef = ref;
     67         }
     68         map.put(key, value);
     69     }
     70 
     71     public void clear() {
     72         cacheRef = null;
     73     }
     74 
     75 }
     76