Java tutorial
//package com.java2s; //License from project: Open Source License import java.util.concurrent.ConcurrentHashMap; public class Main { private static ThreadLocal<ConcurrentHashMap<String, Object>> _map = new ThreadLocal<ConcurrentHashMap<String, Object>>(); public static int getSetCount(String key) { return (Integer) (map().get(countKey(key))); } private static ConcurrentHashMap<String, Object> map() { if (_map.get() == null) _map.set(new ConcurrentHashMap<String, Object>()); return _map.get(); } private static String countKey(String key) { return String.format("__%s:count__", key); } }