Preface

Reactive programming has been around for decades. There has been a few implementations of reactive programming from the time Smalltalk was a young language. However, it has only become popular recently and it is now becoming a trend. Why now you ask? Because it is good for writing fast, real-time applications and current technologies and the Web demand this.

I got involved in it back in 2008, when the team I was part of was developing a multimedia book creator called Sophie 2. It had to be fast and responsive so we created a framework called Prolib, which provided objects with properties which could depend on each other (in other words, we implemented bindings for Swing and much more—transformations, filtering, and so on). It felt natural to wire the model data to the GUI like this.

Of course, this was far away from the functional-like approach that comes with RX. In 2010, Microsoft released RX and, after that, Netflix ported it to Java—RxJava. However, Netflix released RxJava to the open source community and the project became a huge success. Many other languages have their port of RX and many alternatives to it. Now, you can code using reactive programming on your Java backend and wire it to your RxJava's frontend.

This book tries to explain to you what reactive programming is all about and how to use it with RxJava. It has many small examples and it explains concepts and API details in small steps. After reading this book, you will have an idea of RxJava, functional programming, and the reactive paradigm.