Publish ... subscribe ... observe ... event-bus?

… lately some colleagues and me were reasoning on how to do client-side (Browser, JavaScript) communication between web-page components … decoupled … in general I recommend taking a look at an event-bus (aka page-bus), with Java why not take a look at the refcodes-eventbus? … the following “equation” came to mind … simply speaking, the equation Observer pattern + Publish–subscribe pattern = Message broker solves to refcodes-eventbus ;-)”

Lightweight message broker = event-bus?

A lightweight Message broker can be a good solution for requirements doing in-JVM (Java Virtual Machine) communication as of:

  • Signaling events to some event-listener
  • Subscribing your event-listener for some specific events
  • Publishing events merely to interested event-listeners
  • Strongly decoupling the publisher and the subscriber
  • Considering privacy issues (no simple broadcast) …

In the article refcodes-eventbus: Observer + Publish–subscribe = Message broker I describe the refcodes-eventbus accompanied with a plain simple example on how to use it.

The refcodes-eventbus artifact makes use of the refcodes-matcher framework for defining the criteria on when to deliver an event to an event-listener. It also sets on top of the refcodes-observer framework regarding issues around the Observer pattern

Beyond the realms of your JVM …

Combining the refcodes-eventbus with the refcodes-remoting RPC (remote procedure call) framework would extend the refcodes-eventbus beyond the borders of a single JVM. Regarding RPC, see also the article on refcodes-remoting: Face-to-face lightweight remote method calls!