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

Agents


What if you don't care about the result of some operation? You just need to fire something and then forget it. In that case agents are what you need.

Agents also run in separate thread pools, there are two functions that you can use to fire an agent:

  • send: This executes your function in an implicit thread pool

  • send-off: This tries to execute your function in a new thread but there's a change, it will reuse another thread

Agents are the way to go if you want to cause side effects in a transaction; since, they will only be executed after the transaction has completed successfully.

They work in a very simple manner, here is an example usage:

(def agt (agent 0))
(defn sum [& nums]
  (Thread/sleep 5000)
  (println :done)
  (apply + nums))
(send agt sum 10) ;; You can replace send with send-off
                  ;; if you want this to be executed in a different thread
@agt

If you copy and paste the exact previous code you will see a 0 and then a :done message, if you check for the value...