What is the opposite of the observer pattern?

Question

As I understand it, the observer pattern allows for multiple observers to monitor a single subject. Is there a pattern for the opposite scenario? Is there a pattern for a

Answer 1

Yes. It is just another application of the observer pattern.

The Observer adds itself to many Subjects. If you want the same action to be performed no matter Which subject you're observing then this is exactly the same as the Observer pattern you are using.

If you want a separate action depending on which Subject triggered the event then you can use the Action parameter that is passed into the Observer's ActionPerformed method to help determine which subject triggered the event. (these names may change depending on your language or library of choice)