Book Image

Clojure for Java Developers

Book Image

Clojure for Java Developers

Overview of this book

We have reached a point where machines are not getting much faster, software projects need to be delivered quickly, and high quality in software is more demanding as ever. We need to explore new ways of writing software that helps achieve those goals. Clojure offers a new possibility of writing high quality, multi-core software faster than ever, without having to leave your current platform. Clojure for Java developers aims at unleashing the true potential of the Clojure language to use it in your projects. The book begins with the installation and setup of the Clojure environment before moving on to explore the language in-depth. Get acquainted with its various features such as functional programming, concurrency, etc. with the help of example projects. Additionally, you will also, learn how the tooling works, and how it interacts with the Java environment. By the end of this book, you will have a firm grip on Clojure and its features, and use them effectively to write more robust programs.
Table of Contents (14 chapters)
Clojure for Java Developers
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Basics of functional programming


This is a topic that you can read about in lots of different places, and it seems that everyone has their own opinion of what functional programming is. There is however, some common ground that you will find in almost every definition, which relates to the benefits you gain from functional programming, such as:

  • Easier code reuse

  • Functions are easier to test

  • Functions are easier to reason about

In order to get these benefits, you need to take into account the following things:

  • You should think of functions as first class citizens

  • Functions should minimize side effects (they shouldn't change any state)

  • Functions should only depend on their parameters (this is called referential transparency)

Lets take a look at two examples of functions (or methods) in Java to illustrate how, even in Java, you can get benefits from writing functions without side effects and context dependency.

public void payRent(BigDecimal amount) {
  User user = getCurrentUser();
  if(user.payAmount...