How long do I have to wait to eat after a getting tooth filling?

Generally. As far as the filling itself goes, you can eat right away with tooth colored composite fillings, but should wait at least one hour with amalgam (silver) fillings. It's always best you ask your own dentist as this can vary somewhat based upon the size and location of the filling. If you had local anesthesia, you should wait until all the numbness is gone.
Varies. Depends upon the duration of the anesthesia and the type of filling. Most dentists will allow you to eat soft foods right away if you eat on the opposite side of your mouth. Generally you will be able to eat anything within 2-4 hours.
Depends. Two things to consider: 1. Are you still numb from the anesthesia?, 2. Is it a tooth colored filling or an amalgam (silver colored) filling. Obviously, you want the numbness to be gone before eating, so you don't chew yourself instead of / in addition to your food. If the filling is amalgam. You should wait at least a few hours, and no hard chewing for 24 hours. If unsure, ask your dentist.
No numbness. Wait until all the anesthesia has won off and do not eat hard foods o the tooth for 24 hrs.
Filling type? Don't chew as long as you are numb. White fillings are set right away, so there is no need to wait. Less commonly used any mire are silver fillings. If so, avoid chewing pressure until the next day.
Depends. Amalgam filling need time to harden, several hours. Composite (white) fillings are hardened with a light and you can eat as soon as the anesthetic wears off. In or office we use lasers for fillings so the patients don't need shots and they can eat right away.