import java.util.HashMap; import java.util.LinkedList; import java.util.Map; /** * Caching with the LRU (Least Recently Used) algorithm. * */ public class LRUCache { private Map<Object, Object> cache = new HashMap<Object, Object>(); private LinkedList<Object> keyList = new LinkedList<Object>(); private int maxSize; public LRUCache(int maxSize) { if (maxSize < 1) { throw new IllegalArgumentException("LRUCache max size must be greater than 0"); } this.maxSize = maxSize; } public synchronized void put(Object key, Object value) { if (key == null) { return; } keyList.remove(key); keyList.addFirst(key); cache.put(key, value); if (cache.size() > maxSize) { Object lastKey = keyList.getLast(); this.remove(lastKey); } } public synchronized Object get(Object key) { if (key == null) { return null; } Object value = cache.get(key); if (value == null) { return null; } keyList.remove(key); keyList.addFirst(key); return value; } public synchronized Object remove(Object key) { if (key == null) { return null; } Object value = cache.remove(key); if (value == null) { return null; } keyList.remove(key); return value; } public synchronized void clear() { cache.clear(); keyList.clear(); } }
备注
https://stackoverflow.com/questions/322715/when-to-use-linkedlist-over-arraylist
什么时候用LinkedList
什么时候用ArrayList
什么时候用HashMap
什么时候用LinkedHashMap
标签:used,recently,Object,least,value,key,return,keyList,null From: https://www.cnblogs.com/zno2/p/7010271.html