Question

I have a J2EE application that receives and process messages (events). These messages contain various blocks of data. Different types of processing can be triggered depending of the type of data contained in a message.

I would like to have a simple internal event/message bus that can be used by the main processing thread to invoke different post-processors dependent on message content. For example, if a message is received of type A, I would like to be able to send an internal event to all post-processors that have subscribed to events of type A. The post-processors can then work their magic in their own time/thread. It would be nice (though not required) if the post-processors could be added/removed from the application via some sort of plugin-framework.

I understand that there are various message buses available. I am really seeking advice on an appropriate (lightweight) choice or perhaps a design pattern/example to cook my own.

Thanks in anticipation

Answer 1

Guava has and nice EventBus implementation. See the documentation.