Trigger Cocept

Hey there.I want to implement a trigger-system into my game.
I thought of something like that:

Enemies, Traps, Doors, Music, etc. implement an interface namend “Triggerable”
A switch, keyhole, or a simple area within the level, has an Attribute called “whatToTrigger” and is an ArrayList.

But I have no Idea how to put the triggerable Objects into the Trigger of the Swtich/Keyhole/whatever.
Any ideas for that?