Has Federer won all slams in one year?

No, but three times (in 2004, 2006 and 2007) he won three of them (Austalian Open, Wimbledon and Flushing Meadows) in the same year and two times he reached (2006 and 2007) all the four finals in the same year (and he lost only Roland Garros, defeated by Nadal).