Book Image

Clojure High Performance Programming

By : Shantanu Kumar
Book Image

Clojure High Performance Programming

By: Shantanu Kumar

Overview of this book

<p>Clojure is a young, dynamic, functional programming language that runs on the Java Virtual Machine. It is built with performance, pragmatism, and simplicity in mind. Like most general purpose languages, Clojure’s features have different performance characteristics that one should know in order to write high performance code.<br /><br />Clojure High Performance Programming is a practical, to-the-point guide that shows you how to evaluate the performance implications of different Clojure abstractions, learn about their underpinnings, and apply the right approach for optimum performance in real-world programs.<br /><br />This book discusses the Clojure language in the light of performance factors that you can exploit in your own code.</p> <p>You will also learn about hardware and JVM internals that also impact Clojure’s performance. Key features include performance vocabulary, performance analysis, optimization techniques, and how to apply these to your programs. You will also find detailed information on Clojure's concurrency, state-management, and parallelization primitives.</p> <p>This book is your key to writing high performance Clojure code using the right abstraction, in the right place, using the right technique.</p>
Table of Contents (15 chapters)
Clojure High Performance Programming
Credits
About the Author
Acknowledgments
About the Reviewers
www.PacktPub.com
Preface
Index

Concurrency with threads



On the JVM, threads are the de-facto, fundamental instrument of concurrency. Multiple threads live in the same JVM; they share the heap space and compete for resources.

JVM support for threads

JVM threads are the operating system threads. Java wraps an underlying OS thread as an instance of the java.lang.Thread class and builds up an API around it to work with threads. A thread on the JVM has a number of states: New, Runnable, Blocked, Waiting, Timed_Waiting, and Terminated. A thread is instantiated by overriding the run() method of the Thread class or by passing an instance of the java.lang.Runnable interface to the constructor of the Thread class. Invoking the start() method of a Thread instance starts its execution in a new thread. Even when just a single thread is running in the JVM, the JVM would not shut down. Calling the setDaemon(boolean) method of a thread with the argument true tags the thread as a daemon that can be automatically shut down if no other...