public function getUrl() {
        try {
            if ($this->getRequestMethod()!= \Request::HTTP_GET) {
                    throw new \common_exception_NotImplemented('Only GET method is accepted to request this service.');
            }
            
            if(!$this->hasRequestParameter('deliveryId')) {
                $this->returnFailure(new \common_exception_MissingParameter('At least one mandatory parameter was required but found missing in your request'));
            } 
            
            $selectedDelivery = new \core_kernel_classes_Resource($this->getRequestParameter('deliveryId'));
            if(!$selectedDelivery->isInstanceOf(new \core_kernel_classes_Class(TaoOntology::CLASS_URI_DELIVERY))) {
                $this->returnFailure(new \common_exception_NotFound('Delivery not found'));
            }

            $this->returnSuccess(LTIDeliveryTool::singleton()->getLaunchUrl(array('delivery' => $selectedDelivery->getUri())));

        } catch (\Exception $ex) {
             $this->returnFailure($ex);
        }
        
    }