In the Harry Potter books, only house-elves can apparate and disapparate within Hogwarts, as their job requires them to do so, and the jinx preventing apparition is improvised accordingly. Interestingly, in the Harry Potter movies, despite there being security measures to prevent apparition in Hogwarts, the headmaster, Albus Dumbledore was capable of performing this feat. So was Fawkes, the phoenix, and the house-elves.