public function addMappingToRenderer(
        SwatCellRenderer $renderer,
        SwatCellRendererMapping $mapping
    ) {
        if ($renderer->isPropertyStatic($mapping->property)) {
            throw new SwatException(
                sprintf(
                    'The %s property can not be data-mapped',
                    $mapping->property
                )
            );
        }

        $renderer_key = spl_object_hash($renderer);
        $this->mappings[$renderer_key][] = $mapping;
    }