Hands-On Design Patterns with Java

Understanding the publisher-subscriber design pattern

The publisher-subscriber design pattern establishes two entities: a publisher that sends messages based on events and a subscriber that subscribes to those events. With this design pattern, publishers transmit messages and subscribers listen for them and then take the appropriate action or inaction.

As illustrated next, the Publisher publishes events. The Subscribers subscribe to the events. Once an event is heard, the Subscriber provides the computation or processing as appropriate for the event:

Publisher-subscriber design pattern—overview

This design pattern is event-driven and can be ...