Tag Archives: events

Simple CDI Events Example

In this post I will show you how to produce a CDI event and how to handle it even if it is deployed in another application.

The Event class

A simple JSF Page

This page only shows a simple message from the backing bean (the call to the bean produces the bean’s initialization).

Backing Bean

Here we Inject an event (LoggerEvent) via CDI Inject annotation. Then inside the init method annotated with PostConstruct we fire the event with a new instance of the event. This is the simplest way to fire a CDI event. No matter who are listening to this event will be notified.

A simple Logger Event Handler

This class will listen for events annotated with the keyword @Observes. Because of this, it will execute the method. In this case it will print to the console a log message passed to the constructor of the event instance when it was created: Hello from CDI events as you can see in the next picture.

Result (console result)

cdi events
cdi events

AS you can see, it’s just that simple to create a CDi event and listen to it. This technique uses the Observer design pattern here with the help of @Observes annotation.

Feel free to comment. Download the souce code CDIEvents.

Thanks.