| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| package org.codehaus.groovy.runtime.memoize; |
| |
| import org.apache.groovy.util.concurrent.concurrentlinkedhashmap.ConcurrentLinkedHashMap; |
| |
| import javax.annotation.concurrent.ThreadSafe; |
| import java.lang.ref.SoftReference; |
| import java.util.Iterator; |
| import java.util.Map; |
| import java.util.concurrent.ConcurrentMap; |
| |
| /** |
| * A cache backed by a ConcurrentLinkedHashMap |
| */ |
| @ThreadSafe |
| public final class LRUCache<K, V> implements MemoizeCache<K, V> { |
| private final ConcurrentMap<K, V> map; |
| |
| public LRUCache(final int maxCacheSize) { |
| map = new ConcurrentLinkedHashMap.Builder<K, V>() |
| .maximumWeightedCapacity(maxCacheSize) |
| .build(); |
| } |
| |
| @Override |
| public V put(final K key, final V value) { |
| return map.put(key, value); |
| } |
| |
| @Override |
| public V get(final K key) { |
| return map.get(key); |
| } |
| |
| /** |
| * Try to get the value from cache. |
| * If not found, create the value by {@link MemoizeCache.ValueProvider} and put it into the cache, at last return the value. |
| * |
| * The operation is completed atomically. |
| * |
| * @param key |
| * @param valueProvider provide the value if the associated value not found |
| */ |
| @Override |
| public V getAndPut(K key, ValueProvider<? super K, ? extends V> valueProvider) { |
| return map.computeIfAbsent(key, valueProvider::provide); |
| } |
| |
| /** |
| * Remove all entries holding SoftReferences to gc-evicted objects. |
| */ |
| public void cleanUpNullReferences() { |
| synchronized (map) { |
| final Iterator<Map.Entry<K, V>> iterator = map.entrySet().iterator(); |
| while (iterator.hasNext()) { |
| final Map.Entry<K, V> entry = iterator.next(); |
| final Object value = entry.getValue(); |
| |
| if (!(value instanceof SoftReference)) continue; |
| if (((SoftReference) value).get() == null) iterator.remove(); |
| } |
| } |
| } |
| } |