固定长度的Map（采用LRU策略）的实现

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

public class FixedCapacityMap {

 protected static Map<Integer, Long> fixedCapacityCache = Collections.synchronizedMap(new LRUHashMap<>());

 public static Long get(int key) {
   return fixedCapacityCache.get(key);
 }

 public static void put(int key, long value) {
   fixedCapacityCache.put(key, value);
 }

 public static int size() {
   return fixedCapacityCache.size();
 }


 static class LRUHashMap<K, V> extends LinkedHashMap<K, V> {
   private int capacity = 50;
   @Override
   protected boolean removeEldestEntry(Map.Entry<K, V> eldest) {
     return size() > capacity;
   }

 }


}