Event Bus Pattern : A Software News Feed

We often see the Event Bus architectural pattern in notification frameworks and Android development.  This approach provides us with a way to have a news feed mechanism across clients and processes.

The Event Bus Pattern Defined

There are three main players in this event bus pattern.  The players are the sources, the bus, and the listeners.  Within the bus, there are channels.  In this pattern, the listeners subscribe to a channel or channels.  Likewise, the sources post messages to one or more of these.  That allows sources to note something happened.  Likewise, any subscribers will see it.  Note that this is a one-way architecture.  Listeners will not communicate directly with sources.  However, you could have a return bus that listeners are sources for.  Nevertheless, the goal is for the listeners and sources to act without knowledge of each other.  Thus, the items on the channel are "post and forget" messages.

Need To Know Basis

Challenges