001 /** 002 * 003 * Licensed to the Apache Software Foundation (ASF) under one or more 004 * contributor license agreements. See the NOTICE file distributed with 005 * this work for additional information regarding copyright ownership. 006 * The ASF licenses this file to You under the Apache License, Version 2.0 007 * (the "License"); you may not use this file except in compliance with 008 * the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, software 013 * distributed under the License is distributed on an "AS IS" BASIS, 014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 015 * See the License for the specific language governing permissions and 016 * limitations under the License. 017 */ 018 package org.apache.camel.util; 019 020 import java.util.LinkedHashMap; 021 import java.util.Map; 022 023 /** 024 * A Least Recently Used Cache 025 * 026 * @version $Revision: 1.1 $ 027 */ 028 public class LRUCache<K, V> extends LinkedHashMap<K, V> { 029 private static final long serialVersionUID = -342098639681884413L; 030 private int maxCacheSize = 10000; 031 032 public LRUCache(int maximumCacheSize) { 033 this(maximumCacheSize, maximumCacheSize, 0.75f, true); 034 } 035 036 /** 037 * Constructs an empty <tt>LRUCache</tt> instance with the 038 * specified initial capacity, maximumCacheSize,load factor and ordering mode. 039 * 040 * @param initialCapacity the initial capacity. 041 * @param maximumCacheSize 042 * @param loadFactor the load factor. 043 * @param accessOrder the ordering mode - <tt>true</tt> for 044 * access-order, <tt>false</tt> for insertion-order. 045 * @throws IllegalArgumentException if the initial capacity is negative 046 * or the load factor is nonpositive. 047 */ 048 public LRUCache(int initialCapacity, int maximumCacheSize, float loadFactor, boolean accessOrder) { 049 super(initialCapacity, loadFactor, accessOrder); 050 this.maxCacheSize = maximumCacheSize; 051 } 052 053 /** 054 * @return Returns the maxCacheSize. 055 */ 056 public int getMaxCacheSize() { 057 return maxCacheSize; 058 } 059 060 protected boolean removeEldestEntry(Map.Entry entry) { 061 return size() > maxCacheSize; 062 } 063 }