org.apache.activemq.memory.LRUMap Maven / Gradle / Ivy
/**
* 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.memory;
import java.util.LinkedHashMap;
import java.util.Map;
/**
* A simple least-recently-used cache of a fixed size.
*
*
*/
public class LRUMap extends LinkedHashMap{
protected static final float DEFAULT_LOAD_FACTOR = (float) 0.75;
protected static final int DEFAULT_INITIAL_CAPACITY = 5000;
private static final long serialVersionUID = -9179676638408888162L;
private int maximumSize;
public LRUMap(int maximumSize) {
this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, true, maximumSize);
}
public LRUMap(int maximumSize, boolean accessOrder) {
this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, accessOrder, maximumSize);
}
public LRUMap(int initialCapacity, float loadFactor, boolean accessOrder, int maximumSize) {
super(initialCapacity, loadFactor, accessOrder);
this.maximumSize = maximumSize;
}
protected boolean removeEldestEntry(Map.Entry eldest) {
return size() > maximumSize;
}
}