How should a public school teacher discipline unruly students?

The asker of this question e-mailed me the following clarification about the kinds of discipline he uses:

"I mean resorting to school procedures, of course: detentions for being tardy, not letting them use I-pods or MP3, talking on their cell phones during class, eat in class. In short I have to restrict some of their activities which normally are O.K., but since the kids are at school through the state law, and I am expected to enforce the school discipline, am I violating the students individual rights? This is a double question: being a government school teacher and participating in all the games the state educational establishment is imposing on populous, am I a co-participant? And since I am a "ruler" in my class, what is the proper role of "classroom management enforcer" from Objectivist perspective? Could you recommend sound school teacher-student relations if the students are assigned to class which some of them might not be exactly happy about? I am talking about 2-3 kids who cause all the problems when the majority of my students like to learn Spanish. But even these 2-3 are still human beings who are forced by the state to attend school. By punishment I mean no more than reprimanding them or keeping them after school for 20 minutes; but this is still my use of power to subdue them and force them to obey, which kills me as an objectivist. Am I being a jailer in this case?"