public static function getInstance() { if (empty(self::$instance)) { self::$instance = new self(); } return self::$instance; }
public static function getSource($source = self::DB_MYSQL) { switch ($source) { case self::FILE_CSV: return Model_Plant_Source_File_Csv::getInstance(); break; case self::DB_MYSQL: return Model_Plant_Source_Db_Mysql::getInstance(); default: break; } }