data = []; } public function addData($id, $value) { $this->data[$id] = $value; return $this; } public function setData(array $data_array) { $this->data = $data_array; return $this; } public function getDataById($id) { // return null if we don't have it if (!isset($this->data[$id])) return null; return $this->data[$id]; } public function getData() { return $this->data; } }