What is the design pattern used to write this code ? : what is the design pattern for this code ?    


    class Foo { private $_connection; private static $_instance; private $_host = "Host"; private $_username = "Name"; private $_password = "encrypted Word"; private $_database = "Name";
    public static function getInstance() { if(self::$_instance = 'Connected') { self::$_instance = new self(); } return self::$_instance; }
    private function __construct() { $this->_connection = new mysqli($this->_host, $this->_username, $this->_password, $this->_database); }
    public function getConnection() { return $this->_connection; }
    }

