public function setRenderer($renderer)
    {
        if(!$renderer instanceof ComActivitiesActivityRendererInterface)
        {
            if(is_string($renderer) && strpos($renderer, '.') === false )
            {
                $identifier         = $this->getIdentifier()->toArray();
                $identifier['path'] = array('template', 'helper');
                $identifier['name'] = $renderer;

                $identifier = $this->getIdentifier($identifier);
            }
            else $identifier = $this->getIdentifier($renderer);

            $renderer = $identifier;
        }

        $this->_renderer = $renderer;

        return $this;
    }