Events

As we have already mentioned, plugins use the Observer pattern to keep an eye on events and handle them. The Observer pattern is a design pattern in a logical function, which is common to programming. This particular pattern allows listeners to attach to a subject. The subject can initiate a notification (essentially an event), which will cause the listeners to react to the event.

The expressions ‘listener’ and ‘observer’ are interchangeable, as are ‘subject’ and ‘observable’.