| /** |
| * 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.activemq.util; |
| |
| import java.util.LinkedHashMap; |
| import java.util.Map; |
| |
| /** |
| * A Simple LRU Cache |
| * |
| * |
| * @param <K> |
| * @param <V> |
| */ |
| |
| public class LRUCache<K, V> extends LinkedHashMap<K, V> { |
| private static final long serialVersionUID = -342098639681884413L; |
| protected int maxCacheSize = 10000; |
| |
| /** |
| * Default constructor for an LRU Cache The default capacity is 10000 |
| */ |
| public LRUCache() { |
| this(0,10000, 0.75f, true); |
| } |
| |
| /** |
| * Constructs a LRUCache with a maximum capacity |
| * |
| * @param maximumCacheSize |
| */ |
| public LRUCache(int maximumCacheSize) { |
| this(0, maximumCacheSize, 0.75f, true); |
| } |
| |
| /** |
| * 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 |
| * @param loadFactor the load factor. |
| * @param accessOrder the ordering mode - <tt>true</tt> for access-order, |
| * <tt>false</tt> for insertion-order. |
| * @throws IllegalArgumentException if the initial capacity is negative or |
| * the load factor is non-positive. |
| */ |
| |
| public LRUCache(int initialCapacity, int maximumCacheSize, float loadFactor, boolean accessOrder) { |
| super(initialCapacity, loadFactor, accessOrder); |
| this.maxCacheSize = maximumCacheSize; |
| } |
| |
| /** |
| * @return Returns the maxCacheSize. |
| */ |
| public int getMaxCacheSize() { |
| return maxCacheSize; |
| } |
| |
| /** |
| * @param maxCacheSize The maxCacheSize to set. |
| */ |
| public void setMaxCacheSize(int maxCacheSize) { |
| this.maxCacheSize = maxCacheSize; |
| } |
| |
| protected boolean removeEldestEntry(Map.Entry<K,V> eldest) { |
| return size() > maxCacheSize; |
| } |
| } |