Accessing generateURL() from Entity class

I would like to access generateUrl in my entity class. You can access generateUrl in controller class like this:

$url = $this->generateUrl('your_route_name', array(/* parameters */));

Accoring do this article, I should try to 'create a service, and inject the router component in it'. Then I am reading Symfony Docs: Service Container and try configuration, but I still can not make it.

in app/config/config.yml

services:
    router:
        class: ???
        arguments: ???

How can I make router as service?

update

Why I want to use generateUrl in Entity class?

I am using Eko/FeedBundle. It requires to implements getFeedItemLink() in Entity. I need to give URL as return value of this function.