Development Assistance Right Approach to disable / enable pvp & mob spawn

Hello Guys,


I saw loads of plugin which enable / disable pvp and mob spawn.

I'll develop both in a way that will suit my "project", but what I don't know yet is the best practices for this kind of plugin.

I want to have pvp disabled as well mob spawn disabled ( not all mobs, just the agressive ones ) inside my city.
Just because my city shape is irregular ( not square, circle or whatever ) what would be the best approach to do it?

Save all damn coordinates inside a yml and then every time the respective events are fired, run through each possible coordinate and check if pvp / mob spawn is enabled or disabled?

Which API functions are used to perform these actions?

Just to let it clear, I don't want code ( I'm pretty familiar with Java ), what I would love to know is the best practices for this kind of plugin.

Thanks in advance.

Peace,
TF