Code example for ConcurrentHashMap

Methods: get, putIfAbsent

0
	 *  
	 * @param key 
	 * @return 
	 */ 
	public static IFollower get(String key) {
		IFollower fo = pool.get(key);
		if (fo == null) {
			try { 
				fo = new BasicFollower(key);
				pool.putIfAbsent(key, fo);
			} catch (IOException e) {
				LOG.error("Can't create Follower with exception:" + e);
			} 
		} 
		return fo;
	} 
 
	/** 
	 * this method is to remove the follower by key, usually when the follower 
	 * is updated from someone else, or should be shutdown 
	 *