php - open cart how to get current customer info? -

i have created following controller:

class controllercommontestsms extends controller {     function index()     {        //  action     } } 

but if add following line, throws error function undefined:

$this->customer->islogged(); 

class controllercommontestsms extends controller {     function index()     {        if (!$this->customer->islogged()) {          //code execu          }     } } 

this working fine.