JavaScript Evented I/O & more JavaScript Evented I/O & more for the Java Enterprise Ecosystem for the Java Enterprise Ecosystem Niko Köbler ( ) @dasniko {JavaScript}Training Node.js on the JVM Node.js on the JVM

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What is Node.js? What is Node.js? Server-side JavaScript platform built on Google V8 engine What JavaScript has done for the webbrowser, Node.js is doing for the backend server Asyncronous, non-blocking, evented I/O with JavaScript http://nodejs.org var http = require('http'); http.createServer(function (req, res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello World\n'); }).listen(1337, '127.0.0.1'); console.log('Server running at http://127.0.0.1:1337/');

The Event Loop The Event Loop

The cost of I/O The cost of I/O L1-cache 3 cycles L2-cache 14 cycles RAM 250 cycles Disk 41 000 000 cycles Network 240 000 000 cycles

Why JavaScript? Why JavaScript? “ (undefined is not a function!)

Why Java? Why Java?

With Java, we have... With Java, we have...

And now, you wanna tell us And now, you wanna tell us about this about this "brave" "brave" new new (Node-)JS-world? (Node-)JS-world?

Speaking JavaScript Speaking JavaScript “Like it or not, JavaScript is everywhere these days - from browser to server to mobile - and now you, too, need to learn the language or dive deeper than you have. Dr. Axel Rauschmayer http://speakingjs.com

“In four years ... Node.js has experienced phenomenal growth. Node.js is the language of choice for high performance, low latency applications and has been powering everything from robots to API engines to cloud stacks to mobile web sites. Node.js Advisory Board - October 23, 2014

Any application that Any application that can can be be written in JavaScript, written in JavaScript, will will eventually be written in eventually be written in JavaScript JavaScript Atwood's Law http://blog.codinghorror.com/the-principle-of-least-power/

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Integration Integration

Integration Integration

Integration Integration

dynamic dynamic invoke invoke

Nashorn Nashorn JavaScript Enginge on the JVM based on invokedynamic feature competes with Google V8 ECMAScript 5.1 compatible (ES6/ES2015 with Java 9) Seamless interoperability of Java and JavaScript Shell Scripting Language and API Extensions http://openjdk.java.net/projects/nashorn/​ closures, collections & for each, multi-line string literals, string interpolation, __noSuchProperty__, __noSuchMethod__, typed arrays, binding properties, error extensions, conditional catch clause, String functions, and many, many more...

Java and JavaScript Java and JavaScript “ ...are similar than car and carpet are similar.

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Nashorn Nashorn Command Line Client $ $JAVA_HOME/bin/jjs jjs> print('Hello Nashorn!');

Nashorn Nashorn Invoking JavaScript from Java ScriptEngine engine = new ScriptEngineManager() .getEngineByName("nashorn"); engine.eval("print('Hello Nashorn!');"); engine.eval(new FileReader("scriptfile.js")); Invocable invocable = (Invocable) engine; Object result = invocable.invokeFunction( "jsSayHello", "Nashorn");

Nashorn Nashorn Invoking Java from JavaScript package my.package; public class MyJavaClass { static String sayHello(String name) { return String.format("Hello %s from Java!", name); } } var MyJavaClass = Java.type('my.package.MyJavaClass'); var result = MyJavaClass.sayHello('Nashorn'); print(result); // Hello Nashorn from Java!

Nashorn Nashorn Listing Docker Containers via REST-Call from Shell #!/usr/bin/jjs -fv var host = "DOCKER_HOST" var dockerUri="http://${host}:5555/containers/json"; var command = "curl ${dockerUri}"; $EXEC(command); var containers = JSON.parse($OUT); for each(container in containers){ print("${container.Image} / ${container.Names[0]} / ${container.Status}"); } (by ) Adam Bien

Avatar Avatar The Oracle solution The Oracle solution † †

Avatar 2.0 Avatar 2.0 Inter-thread communication Message Bus Shared State (Map API: Key-Value-Store) Model-Store-API JPA (Eclipselink) / JDBC based / https://avatar.java.net https://avatar-js.java.net

Avatar 2.0 Avatar 2.0

by by project:odd project:odd @RedHat @RedHat http://nodyn.io

also based on invokedynamic REPL / command line Java interaction / embedding http://dynjs.org Nashorn is on its way! Nashorn is on its way!

“ Netty is an asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients. http://netty.io Netty Netty

Node.js Architecture Node.js Architecture

Nodyn Architecture Nodyn Architecture “ more JavaScript than Node.js

“ Vert.x is a lightweight, high performance application platform for the JVM that's designed for modern mobile, web, and enterprise applications. Polyglott* Simplicity Scalability Concurrency Distributed Event Bus** http://vertx.io *) Java, JavaScript, Ruby, Groovy, Python, Scala, Clojure, Ceylon **) using Hazelcast In-Memory Data Grid ( ) hazelcast.org

vertx2-core vertx2-core This module exposes the vert.x 2.x eventbus to node.js clients. https://github.com/nodyn/vertx2-core mod-nodyn mod-nodyn This supports running Node.js workloads inside of Vert.x. https://github.com/nodyn/mod-nodyn

Beer-as-a-Service Beer-as-a-Service https://github.com/dasniko/beer-as-a-service

var http = require("http"); var vertx = require("vertx2-core"); var registration = vertx.eventbus.register("bar", function(message) { var amount = message.body.amount; console.log("BAR: Someone ordered " + amount + " beer(s)."); message.reply({wait_time: amount * 1.75}); }); var server = http.createServer(function(request, response) { var parts = request.url.split("/"); var amount = parts[1]; vertx.eventbus.send("bar", {amount: amount}, function(message) { response.write(amount + " beer(s) will be ready in " + message.body.wait_time + " minutes"); response.end(); }); }); server.listen(9000, function() { console.log( "Beer-Server is listening on port 9000" ); }); beer-as-a-service.js run with nodyn

var http = require("http"); var vertx = require("vertx2-core"); var server = http.createServer(function(request, response) { var parts = request.url.split("/"); var amount = parts[1]; vertx.eventbus.send("bar", {amount: amount}, function(message) { response.write(amount + " beer(s) will be ready in " + message.body.wait_time + " minutes"); response.end(); }); }); server.listen(9000, function() { console.log( "Beer-Server is listening on port 9000" ); }); beer-web.js beer-bar.js var eventBus = require("vertx/event_bus"); eventBus.registerHandler("bar", function(message, replier) { java.lang.System.err.println("BAR: Someone ordered " + message.amount + " beer(s)"); replier({wait_time: message.amount * 1.75}); }); java.lang.System.err.println("The BAR is open!"); run with vertx in cluster mode

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Conclusion Conclusion JavaScript is an emerging language and widely adopted Node.js / IO.js is very popular Operations, monitoring and integration lacks JVM is Enterprise environment of choice (and all the above lacks are already solved) Run JavaScript on the JVM thanks to invokedynamic (Nashorn, DynJS) Re-use your infrastructures and libraries with Node Nodyn from Red Hat Re-use of Node API module, integration of Netty and Vert.x Process-bindings in Java/JavaScript Embed Node.js apps into your Java applications Run Node.js apps in distributed environments

Avatar & Nodyn Avatar & Nodyn @ JavaMagazin @ JavaMagazin https://jaxenter.de/ausgaben/java-magazin-3-15 https://jaxenter.de/ausgaben/java-magazin-1-15

Thank you! Thank you! Questions? Questions? Contact: @dasniko niko@n-k.de http://slides.com/dasniko/nodejs-jvm