Is Java needed when implementing Search Restrictions?

Hy experts, I have one doubt about search restrictions. I've read documentation about restriction but I have this doubt:

If I create a new search restriction by impex there it's no need to implement java code?

I just execute the impex with the restriction and works, or I have to activate restrictions by java. If i have to activate it by java, what class should I implement, or what do I need to do. I've no idea.

Thanxs.