Create A Least Recently Used Cache based on LinkedHashMap in Java

Description

The following code shows how to create A Least Recently Used Cache based on LinkedHashMap.

Example


/*  w w w .  ja va  2s  .  c o  m*/
/**
 * 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.
 */

import java.util.LinkedHashMap;
import java.util.Map;

/**
 * A Least Recently Used Cache
 *
 * @version $Revision: 747062 $
 */
public class LRUCache<K, V> extends LinkedHashMap<K, V> {
    private static final long serialVersionUID = -342098639681884413L;
    private int maxCacheSize = 10000;

    public LRUCache(int maximumCacheSize) {
        this(maximumCacheSize, 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 the max capacity.
     * @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;
    }

    /**
     * Returns the maxCacheSize.
     */
    public int getMaxCacheSize() {
        return maxCacheSize;
    }

    protected boolean removeEldestEntry(Map.Entry entry) {
        return size() > maxCacheSize;
    }
}




















Home »
  Java Tutorial »
    Java Collection »




Java ArrayList
Java Collection
Java Comparable
Java Comparator
Java HashMap
Java HashSet
Java Iterator
Java LinkedHashMap
Java LinkedHashSet
Java LinkedList
Java List
Java ListIterator
Java Map
Queue
Java Set
Stack
Java TreeMap
TreeSet