code: public RunTime getDetail(String description){
  		RunTime child = detail.get(description);
  		if (child.getDescription() == null){
  			child.setDescription(description);
  		}
  		return child;
  	}
docs: Get specified detail record, if it does not exist yet, create it first.<br>
  获得指定的详细记录，如果不存在则先创建一个。
  
  @param description  description of the detail record.<br>
  这条详细记录的description。
  @return  The detail record with specified description.<br>
  具有指定description的详细记录。