Introduction to Programming

Message-driven system

Vert.x has a feature that directly supports both the message-driven architecture and EDA. It is called an event bus. Any verticle has access to the event bus, and can send any message to any address (which is just a string) using the io.vertx.core.eventbus.EventBus class, or its cousin, io.vertx.rxjava.core.eventbus.EventBus. We are only going to use the latter, but similar (not rx-fied) functionality is available in io.vertx.core.eventbus.EventBus, too. One, or several, verticles can register themselves as a message consumer for a certain address. If several verticles are consumers for the same address, then the rxSend() method of EventBus delivers the message only to one of these consumers, using a round-robin algorithm ...