| /* |
| * 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.netbeans.modules.parsing.lucene; |
| |
| import java.util.ArrayDeque; |
| import java.util.Collection; |
| import java.util.Iterator; |
| import java.util.LinkedHashMap; |
| import java.util.Map; |
| import java.util.Map.Entry; |
| import java.util.concurrent.locks.ReadWriteLock; |
| import java.util.concurrent.locks.ReentrantReadWriteLock; |
| import org.netbeans.api.annotations.common.NonNull; |
| |
| /** |
| * |
| * @author Tomas Zezula |
| */ |
| final class LRUCache<K,V extends Evictable> { |
| |
| private final LinkedHashMap<K, V> cache; |
| private final ReadWriteLock lock; |
| |
| public LRUCache (final EvictionPolicy<? super K,? super V> policy) { |
| this.lock = new ReentrantReadWriteLock(); |
| this.cache = new LinkedHashMap<K, V>(10,0.75f,true) { |
| @Override |
| protected boolean removeEldestEntry(Entry<K, V> eldest) { |
| final boolean evict = policy.shouldEvict(this.size(), eldest.getKey(), eldest.getValue()); |
| if (evict) { |
| eldest.getValue().evicted(); |
| } |
| return evict; |
| } |
| }; |
| } |
| |
| public void put (final K key, final V evictable) { |
| assert key != null; |
| assert evictable != null; |
| this.lock.writeLock().lock(); |
| try { |
| this.cache.put(key, evictable); |
| } finally { |
| this.lock.writeLock().unlock(); |
| } |
| } |
| |
| public V get(final K key) { |
| assert key != null; |
| this.lock.readLock().lock(); |
| try { |
| return this.cache.get(key); |
| } finally { |
| this.lock.readLock().unlock(); |
| } |
| } |
| |
| public V remove (final K key) { |
| assert key != null; |
| this.lock.writeLock().lock(); |
| try { |
| return this.cache.remove(key); |
| } finally { |
| this.lock.writeLock().unlock(); |
| } |
| } |
| |
| @NonNull |
| public Collection<? extends V> clear() { |
| final Collection<V> res = new ArrayDeque<>(); |
| this.lock.writeLock().lock(); |
| try { |
| for (Iterator<Entry<K, V>> it = this.cache.entrySet().iterator(); it.hasNext();) { |
| Map.Entry<K,V> e = it.next(); |
| res.add(e.getValue()); |
| it.remove(); |
| } |
| } finally { |
| this.lock.writeLock().unlock(); |
| } |
| return res; |
| } |
| |
| @Override |
| public String toString () { |
| this.lock.readLock().lock(); |
| try { |
| return this.cache.toString(); |
| } finally { |
| this.lock.readLock().unlock(); |
| } |
| } |
| |
| } |