ch.qos.logback.classic.pattern.LRUCache Maven / Gradle / Ivy
/**
* Logback: the reliable, generic, fast and flexible logging framework.
* Copyright (C) 1999-2009, QOS.ch. All rights reserved.
*
* This program and the accompanying materials are dual-licensed under
* either the terms of the Eclipse Public License v1.0 as published by
* the Eclipse Foundation
*
* or (per the licensee's choosing)
*
* under the terms of the GNU Lesser General Public License version 2.1
* as published by the Free Software Foundation.
*/
package ch.qos.logback.classic.pattern;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
/**
* An lru cache based on Java's LinkedHashMap.
*
* @author Ceki Gulcu
*
* @param
* @param
*/
public class LRUCache extends LinkedHashMap {
private static final long serialVersionUID = -6592964689843698200L;
final int cacheSize;
public LRUCache(int cacheSize) {
super((int) (cacheSize*(4.0f/3)), 0.75f, true);
if(cacheSize < 1) {
throw new IllegalArgumentException("Cache size cannnot be smaller than 1");
}
this.cacheSize = cacheSize;
}
protected boolean removeEldestEntry(Map.Entry eldest) {
return (size() > cacheSize);
}
List keyList() {
ArrayList al = new ArrayList();
al.addAll(keySet());
return al;
}
}