/**
     * @return ExternalLinkHandlerBase
     */
    public function externalLinkHandler()
    {
        if ( !empty($this->configurationExternal) && !is_null($this->configurationExternal) )
        {
            $externalLinkHandlerName = $this->configurationExternal->externalLinkHandler();
            return ExternalLinkHandlerBase::factory( $externalLinkHandlerName, $this->attribute('id') );
        }

        return null;
    }