#eventbus

Guava EventBus Spring In last two tutorial you saw how to get started with Google Guava EventBus. In this I will show you how to integrate Guava EventBus with Spring framework. If you are seriously looking to integrate Guava EventBus to your project then I will suggest read my next Guava EventBus Spring advanced integration tutorial. Let’s get started and see first how to integrate EventBus with…

Android requires that you do all network processing on non-UI threads. This is good business as it means unexpected exceptions aren't going to crash your app. It can be a little problematic when you need to be notified of the different outcomes of your various network activity. You need to notify an activity, it needs to notify one of it's components.

The Callback Approach

https://gist.github.com/3795510

https://gist.github.com/3795572

https://gist.github.com/3795616

The Guava EventBus Approach

https://gist.github.com/3795675

You have to define those events but they can be empty or you can wrap anything you need in them.

https://gist.github.com/3795689

Then all you have to do is subscribe for the event from the activity. It doesn't matter what you call the method... what matters is the parameter must match an event that will be put on the message bus.

https://gist.github.com/3795715

Why is the event bus better? 

Eventbus is a great java library for a loosly coupled architecture. At the beginning the usage was a little bit confusing for me, but the JavaDocs are a good. A good start should be the Apache Pivot article linked on the homepage.

Eventbus uses a SwingEventService as standard for event publishing and if you do not use Swing then this can lead to problems. See this post on Developmentality for more details.

I wanted to use the ThreadSafeEventService instead of the SwingEventService. First I was just setting it programmatically. I build a little Scala wrapper for this, so it was working for me. But it was nicer to have it in my Spring context configuration. You can provide Eventbus with a service implemetation through a system property. But instead having to define this on the command line the Spring solution feels better to me. For one that knows Spring (not me) this is easy accomplished with the following configuration (gist):