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

Exposing your code to Java


If you want to be able to use Clojure code from other JVM languages, in Clojure, there are a couple of ways in which you can do it:

  • You can generate new Java classes and use them as you normally would; it can implement some interface or extend from some other class

  • You can generate a proxy on the fly, this way you can implement a contract (in the form of a class or an interface) that some framework requires with little code and effort

  • You can use the clojure.java.api package to call Clojure functions directly from Java

Note

You can find more information on how this works at the following location: http://www.falkoriemenschneider.de/a__2014-03-22__Add-Awesomeness-to-your-Legacy-Java.html.

Let's have a look at how we can define a Java class.

Create a new namespace called thumbnails.image-java and write the following code:

(ns thumbnails.image-java
  (:require [thumbnails.image :as img])
  (:gen-class
    :methods [[loadImage [java.io.InputStream] java.awt.image.BufferedImage...