static std::string get_file_name(std::string device_id, plp::Date *ltime);
static void store(std::string device_id, std::list<std::string> *string_list);
void load();
+ Data *get_sum();
Data *get_delta();
Data *get_mean();
+ Data *get_max();
+ Data *get_min();
w1::Data *get_oldest_data();
w1::Data *get_newest_data();
w1::DataRange *get_oldest_and_newest_data();