UFO Eventbus

UFO Event Bus (Ultra Fast Object-oriented Event bus) is a powerful asynchronous, lightweight and scalable publish/subscribe event system written in Java.

It was inspired by Greenrobot eventbus, but basically coded from scratch.

Latest Version 1.0.2

Requirements

Minimum Java version: 8
Minimum Android version: 8.0 minSdkVersion 26

Main features

completely asynchronous
parallel and scalable
very tiny (~50k jar)
performs well with Android and Java
is fast in almost every situation and loads and can be configured
when used with Java >= 9 is compiled as module increasing encapsulation
it has no dependencies but only uses SLF4J as logging facade
can simplify the communication between components since it decouples event posters and listeners
has advanced features like listener priorities, events inheritance, listeners inheritance, inbound event order
entirely documented
the code is clean, testable, compact and very easy to understand and maintain
is completely covered with a large number of unit tests

Goals

Provide a simple-to-use library to allow messaging within the app's objects
Create a completely asynchronous, fast and reliable message passing system
Make the code as cleaner and testable as possible
Don't rely on any other third-party library except than standard Java libraries
Obtain a jar as small as possible
Write good documentation for the library usage and internals

How to add Ufo Eventbus dependency in your project

Gradle:

dependencies {
    implementation "it.rebirthproject:ufo-event-bus:1.0.2"
}

Maven:

<dependency>
    <groupId>it.rebirthproject</groupId>
    <artifactId>ufo-event-bus</artifactId>
    <version>1.0.2</version>
</dependency>

Quick Start

1. Create an event:

// Create an event as a simple Java class with necessary fields
// Most of the times a simple POJO (Plain Old Java Object) with getters and setters should be enough
public class Event { /* Add fields if needed */ }

2. Create an event listener:

import it.rebirthproject.ufoeb.eventannotation.Listen;

// Create a listener for the event using the '@Listen' annotation
public class ListenerForEvent {
    
    @Listen
    public void someMethod(Event event) {
      	// Do something useful here.. Maybe using some data taken from the event...
    }
}

3. Create the bus, register the listeners and send the events:

// Instantiate the listener
ListenerForEvent listener = new ListenerForEvent();

// Create the Eventbus using the builder
// The default values apply for almost every situation, but
// read how to configure advanced bus features when needed
EventBus ufoEventBus = new EventBusBuilder().build();

// Register the listener on the bus
ufoEventBus.register(listener); // The 'register' method throws an EventBusException

// Post messages on the bus. This will call the listener method!
ufoEventBus.post(new Event()); // The 'post' method throws an EventBusException

4. Shutdown the bus

//This will shutdown gracefully the UFO eventbus' infrastructure
ufoEventBus.shutdown();

Internal Architecture Overview and detailed documentation

You can read detailed documentation here.

You can access the javadoc documentation here.

Examples of usages

How to use the bus in Android here.

How to use the bus with JavaFX here.

How to use the bus with plain Java here.

How to use the bus with Libgdx here.

Benckmarks with jmh

Some detailed benchmarks for the UFO eventbus using jmh framework here.

Similar benchmarks for Greenrobot eventbus using jmh framework here.

Roadmap

Right now the next big things for the bus will be:

event runtime filters (block at runtime the delivery of an event using a filter)
rework the exception system if necessary or asked

Contributors

If you would like to help, but don't know where to start, please note that finding bugs and debugging the code is always a good start. Simple Pull Requests that fix anything other than UFO Event Bus core code (documentation, JavaDoc, typos, test cases, etc) are always appreciated and would be merged quickly. However, if you want or feel the need to change the main code or add a new functionality, please do not issue a pull request without creating a new issue and discussing your desired changes, before you start working on it. It would be a shame to reject your pull request if it might not align with the project's goals, design expectations or planned functionality.

For direct communications, you can use this email

Credits and License

Current website under creation Rebirth Project

Ufo Eventbus binaries and source code can be used according to the Apache License, Version 2.0.

Rebirth-Project / ufo-event-bus