Finjan Event bus

What is an event bus?

Finjan is an event bus that allows for post/subscribe style communication between components. They're designed to replace large condition managers to call groups of methods. Listeners are subscribed to the event which then are called when events are posted.

Why use Finjan?

Finjan is a performant and lightweight event bus that simplifies code, that doesn't heavily rely on java's expensive reflection operations thus making it far more performant than other popular event busses. In exchange for less runtime safety guarantees.

• simple and lightweight
• performant
• minimal dependencies Finjan uses runtime class generation with ow2-asm to create invokers to call methods, which makes it significantly faster than others. However currently it does not contain as many features or safety guarantees that others do.

How to use Finjan

1. Defining an event listener

class EventBusListener {
    
    //This method will now listen to all RecordUpdateEvent events
    @EventHandler
    public void onRecordUpdate(RecordUpdateEvent event) {
        event.getValue();
        //...
    }
}

2. Instantiating an event bus

EventManager eventBus = new EventManager();

3. subscribe/unsubscribe an instance of the listener

eventBus.subscribe(listener);
eventBus.unsubscribe(listener);

4. Posting an event

eventBus.post(new RecordUpdateEvent(...));