| /** |
| * 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.apache.camel.util; |
| |
| import java.io.Serializable; |
| import java.util.Collection; |
| import java.util.Map; |
| import java.util.Set; |
| import java.util.concurrent.atomic.AtomicLong; |
| |
| import com.googlecode.concurrentlinkedhashmap.ConcurrentLinkedHashMap; |
| |
| /** |
| * A Least Recently Used Cache |
| * |
| * @version |
| */ |
| public class LRUCache<K, V> implements Map<K, V>, Serializable { |
| private static final long serialVersionUID = -342098639681884414L; |
| |
| private int maxCacheSize = 10000; |
| private final AtomicLong hits = new AtomicLong(); |
| private final AtomicLong misses = new AtomicLong(); |
| private ConcurrentLinkedHashMap<K, V> map; |
| |
| public LRUCache(int maximumCacheSize) { |
| this(maximumCacheSize, maximumCacheSize); |
| } |
| |
| /** |
| * Constructs an empty <tt>LRUCache</tt> instance with the |
| * specified initial capacity, maximumCacheSize,load factor and ordering mode. |
| * |
| * @param initialCapacity the initial capacity. |
| * @param maximumCacheSize the max capacity. |
| * @throws IllegalArgumentException if the initial capacity is negative |
| * or the load factor is non positive. |
| */ |
| public LRUCache(int initialCapacity, int maximumCacheSize) { |
| map = new ConcurrentLinkedHashMap.Builder<K, V>() |
| .initialCapacity(initialCapacity) |
| .maximumWeightedCapacity(maximumCacheSize).build(); |
| // super(initialCapacity, loadFactor, accessOrder); |
| this.maxCacheSize = maximumCacheSize; |
| } |
| |
| @Override |
| public V get(Object o) { |
| V answer = map.get(o); |
| if (answer != null) { |
| hits.incrementAndGet(); |
| } else { |
| misses.incrementAndGet(); |
| } |
| return answer; |
| } |
| |
| @Override |
| public int size() { |
| return map.size(); |
| } |
| |
| @Override |
| public boolean isEmpty() { |
| return map.isEmpty(); |
| } |
| |
| @Override |
| public boolean containsKey(Object o) { |
| return map.containsKey(o); |
| } |
| |
| @Override |
| public boolean containsValue(Object o) { |
| return map.containsValue(0); |
| } |
| |
| @Override |
| public V put(K k, V v) { |
| return map.put(k, v); |
| } |
| |
| @Override |
| public V remove(Object o) { |
| return map.remove(o); |
| } |
| |
| @Override |
| public void putAll(Map<? extends K, ? extends V> map) { |
| this.map.putAll(map); |
| } |
| |
| @Override |
| public void clear() { |
| map.clear(); |
| resetStatistics(); |
| } |
| |
| @Override |
| public Set<K> keySet() { |
| return map.ascendingKeySet(); |
| } |
| |
| @Override |
| public Collection<V> values() { |
| return map.ascendingMap().values(); |
| } |
| |
| @Override |
| public Set<Entry<K, V>> entrySet() { |
| return map.ascendingMap().entrySet(); |
| } |
| |
| /** |
| * Gets the number of cache hits |
| */ |
| public long getHits() { |
| return hits.get(); |
| } |
| |
| /** |
| * Gets the number of cache misses. |
| */ |
| public long getMisses() { |
| return misses.get(); |
| } |
| |
| /** |
| * Returns the maxCacheSize. |
| */ |
| public int getMaxCacheSize() { |
| return maxCacheSize; |
| } |
| |
| /** |
| * Rest the cache statistics such as hits and misses. |
| */ |
| public void resetStatistics() { |
| hits.set(0); |
| misses.set(0); |
| } |
| |
| @Override |
| public String toString() { |
| return "LRUCache@" + ObjectHelper.getIdentityHashCode(this); |
| } |
| } |