code: public String getAssignedRealNode(Object factor) {
  		if(nodes.size() <= 1)return JobContext.getContext().getNodeId();
  		Long key = hash(factor.toString());
  		SortedMap<Long, String> tailMap = nodes.tailMap(key);
  		if (tailMap.isEmpty()) {
  			key = nodes.firstKey();
  		} else {
  			key = tailMap.firstKey();
  		}
  		return nodes.get(key);
  	}
docs: 根据hash因子获取分配的真实节点
  
  @param factor
  @return