private function buildClassNode(core_kernel_classes_Class $class, core_kernel_classes_Class $parent = null)
    {
    	$label = $class->getLabel();
        $label = empty($label) ? __('no label') : $label;

        return array(
            'data' 	=> _dh($label),
            'type'	=> 'class',
            'attributes' => array(
                'id' => tao_helpers_Uri::encode($class->getUri()),
                'class' => 'node-class',
                'data-uri' => $class->getUri(),
                'data-classUri' => is_null($parent) ? null : $parent->getUri(),
                'data-signature' => $this->getSignatureGenerator()->generate($class->getUri()),
            )
        );
    }