A Least Recently Used Cache : LinkedHashMap « Collections « Java Tutorial

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 * 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,
 * 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;

9.27.1.What you can do with a LinkedHashMap.
9.27.2.Get Size of Java LinkedHashMap
9.27.3.Get Set view of Keys from Java LinkedHashMap
9.27.4.Iterate through the values of Java LinkedHashMap
9.27.5.Check if a particular element exists in Java LinkedHashSet
9.27.6.Check if a particular key exists in Java LinkedHashMap example
9.27.7.Check if a particular value exists in Java LinkedHashMap example
9.27.8.Copy all elements of Java LinkedHashSet to an Object Array
9.27.9.Remove all values from Java LinkedHashMap
9.27.10.Remove value from Java LinkedHashMap
9.27.11.A Least Recently Used Cache