Mutual notification patterns

Question

Propose to consider the following problem.

Suppose we have some composite object. Are there patterns that describe the solution of mutual notification of composite object parts, when states of these parts are changed

Answer 1

[EN]May be, EventBus, where all parts of object publish their events and subscribe.

[RUS]Может попробовать EventBus, где части объекта публикуют свои события и подписываются на события других частей

Answer 2

Yes, the Mediator pattern from the original Design Patterns book.