Виктор Гамов — Носороги на воле: прикладные возможности использования JavaScript в разработке на Java

JavaScript является мощным и гибким динамически-типизированным языком. JVM давно зарекомендовала себя как надежная, стабильная и высоко-производительная платформа для разработки и запуска приложений.

Одной из сильных сторон JVM является возможность исполнять код, написанный на разных языках, в том числе JavaScript. С использованием возможностей JavaScript, вы можете сокращать время разработки, используя JavaScript как прикладной DSL для ваших приложений.

Эта презентация о подходах и фреймворках с открытым исходным кодом, которые позволяют использовать Java и JavaScript в одном приложении. Участники познакомятся с текущем состоянием полиглот-фрейворков, в которых JavaScript и Java работают бок о бок.

В программе:
- Расставим все точки над i в вопросах использования Nashorn для server- и client-side разработчиков.
- Посмотрим как интегрировать JavaScript код и NodeJS библиотеки в Java приложение.
- Посмотрим на существующие проекты, в которых используется Java-JavaScript взаимодействие, в том числе Avatar, VertX и другие.
- Проведем сессию вопросов и (если получится) ответов.

Как обычно, вас ждет живое неформальное общение и масса позитива.

Transcript

1. www.faratasystems.com // follow me : twitter.com/gamussa Rhinoceros on the Loose Viktor Gamov Senior Software ENGINEER, Farata Systems JUGMSK, MOSCOW, RUSSIA 2014 Applied Real-World Projects with Java and JavaScript
2. “May you live in interesting times” Chinese curse
3. Why you’re here ★you're excited about JDK8 features
5. Why you’re here ★you're excited about JDK8 features ★JavaScript enthusiast ★you are listener of #razborpoletov podcast
7. Who is talking? ★Software engineer and consultant
8. WE BUILD APPLICATIONS. WE CREATE IT. YOU OWN IT.
9. Who is talking? ★Software engineer and consultant ★co-author and JUG co-lead
10. DO you even javascript ?
12. http://enterprisewebbook.com Available in stores
13. http://enterprisewebbook.com
14. Part one
15. Part one Javascript for java developers
16. Not-so-distant pasT Java devs about javascript I don’t care
17. Everybody knows how to javascript
18. MANY good Parts
19. Present Java devs about javascript Gotta learn more
20. Objects var obj2 = {prop: 42}; // Store the data about Fox Mulder
 var person = { 
 lastName: "Fox",
 firstName: "Mulder",
 age: 53 }; var obj = {};
21. // Declaring function
 function calcTaxes(income, dependent){
 // do stuff
 } Functions // Invoking function
 calcTaxes(5000, 2);
 var myTaxes = calcTaxes(5000, 2); // declaration and invocation at the same time
 // IIFE - immediate invoked function expression 
 (function calcTaxes(income, dependent){
 // do stuff
 })(); // Assigning function literal to a variable
 var calcTaxes = function (income, dependent){
 // do stuff
 };
22. Assigning a Function to Object Property person.doTaxes(5000, 2); person.doTaxes = function (income, dependent) {
 // do stuff 
 };
23. Object Methods in Literals var person2 = {
 lastName: "Fox",
 firstName: "Mulder",
 age: 53,
 doTaxes: function (income, dependent) {
 // do stuff
 }
 }; person2.doTaxes(5000, 2);
24. Constructor function function Tax(income, dependents) {
 // Do something here 
 }
 
 // Creating 2 Tax objects 
 var t1 = new Tax(50000, 3);
 var t2 = new Tax(68000, 1);
25. prototype // Constructor function Person 
 function Person(name, title) {
 this.name = name;
 this.title = title;
 this.subordinates = [];
 }
 
 // Constructor function Employee
 function FbiAgent(name, title) {
 this.name = name;
 this.title = title;
 }
 
 FbiAgent.prototype = new Person();
 
 var emp = new FbiAgent("Dana Scully", "Special Agent");
26. 
 print(3[3]);

28. Number.prototype[3] = ”jugmsk”; 
 print(3[3]);

29. www.destroyallsoftware.com/talks/wat
30. Part TWO
31. Part TWO NASHORN: JSR-233 and beyond
32. JAVAScript is everywhere ★v8 and nodejs ★Rhino was here for years ★Here comes nashorn
33. What is Nashorn?
34. Ultimate invokedynamic consumer 100% pure Java implementation 100% ECMAScript 5.1 compliant JavaScript Engine for JVM What is Nashorn? 100% compiled to bytecode, no interpreter http://www.1001ausmalbilder.de/ausmalbilder/gross/ausmalbild-nashorn-7.jpg
35. HOW To USE NASHORN? ★ The only API is JSR-223: javax.scripting.* ★ Java from JavaScript and vice versa ★ Create and manipulate Java/JavaScript objects ★ Extend Java classes ★ Implement Java interfaces
36. ScriptEngineManager factory = new ScriptEngineManager();
 ScriptEngine engine = factory.getEngineByName("nashorn");
 
 engine.eval("Number.prototype[3] = "jugmsk"; print(3[3]);")
37. String[] options =
 new String[] {
 "--persistent-code-cache",
 "--class-cache-size=50",
 “—no-java"}; * 
 NashornScriptEngineFactory factory = new NashornScriptEngineFactory();
 NashornScriptEngine engine =
 (NashornScriptEngine) factory.getScriptEngine(options); 
 engine.eval("Number.prototype[3] = 'jugmsk'; print(3[3]);"); * jjs -xhelp http://cr.openjdk.java.net/~sundar/jdk.nashorn.api/8u40/javadoc/jdk/nashorn/api/scripting/NashornScriptEngineFactory.html
38. String[] options =
 new String[] {
 "--persistent-code-cache",
 "--class-cache-size=50",
 “—no-java"}; * 
 NashornScriptEngineFactory factory = new NashornScriptEngineFactory();
 NashornScriptEngine engine =
 (NashornScriptEngine) factory.getScriptEngine(options); 
 engine.eval("Number.prototype[3] = 'jugmsk'; print(3[3]);"); * jjs -xhelp http://cr.openjdk.java.net/~sundar/jdk.nashorn.api/8u40/javadoc/jdk/nashorn/api/scripting/NashornScriptEngineFactory.html
39. https://wiki.openjdk.java.net/display/Nashorn/Nashorn+extensions var System = Java.type('java.lang.System');
 System.out.println(10); // 10
 System.out["println"](11.0); // 11.0
 System.out["println(double)"](12); // 12.0 Parameter overloading var Date = Java.type('java.util.Date');
 var date = new Date();
 date.year += 1900;
 print(date.year); // 2014 Java Beans print(__FILE__, __LINE__, __DIR__); Whereis Load Scripts // show example with underscore.js
41. https://twitter.com/volyihin/status/524215089466187776
42. SHELL Scripting Extend app functionality on runtime 1 2 3 JAVASCRIPT on JVM USE cASES WEB-content generation 4 provide extension points for application https://docs.oracle.com/javase/8/docs/technotes/guides/scripting/nashorn/shell.html
43. Demo
44. Part Three
45. Part Three Java and NODE.JS
46. Node.js
48. Avatar.js ftw! https://avatar-js.java.net
49. Demo
50. Take first available express demo from internet what could go wrong
51. https://github.com/hacksparrow/ninja-store
52. import com.oracle.avatar.js.Server;
 
 import java.io.File;
 import java.lang.reflect.Field;
 
 public class Main {
 
 static {
 try {
 final Field sysPathsField = ClassLoader.class.getDeclaredField("sys_paths");
 sysPathsField.setAccessible(true);
 sysPathsField.set(null, null);
 System.setProperty("java.library.path",
 new File(Main.class.getResource("/libavatar-js.dylib").getPath())
 .getParentFile().getCanonicalPath());
 System.loadLibrary("avatar-js");
 } catch (Throwable t) {
 throw new RuntimeException(t);
 }
 }
 
 public static void main(String[] args) throws Throwable {
 Server.main(Main.class.getResource("/app.js").getPath());
 }
 } credits: https://github.com/danveloper/midwestjs-2014-nashorn/blob/master/node-app/src/main/java/midwestjs/nashorn/Main.java
54. NASHORN in «wild life» ★ vert.x ★ Avatar 2.0 ★ nodyn.io
55. ★polyglot platform ★Develop with Java, Javascript, jRuby, Groovy, jython, clojure, ★Scala, php, ceylon ★integration with nashorn ★https://github.com/vert-x/mod-lang-nashorn ★Event bus (down to the browser) ★Distributed data (in v.3) ★Open source: EPL / Apache vertx.io
56. Avatar 2.0 ★polyglot platform (sort oF) ★integration with nashorn ★Node api ★Model-Store api ★Event bus ★Distributed data ★not open yet
57. ★NODE api for Java platform ★USES DYNJS - ALTERNATIVE JAVASCRIPT ENGINE ★WILL BE INTEGRATED WITH VERTX nodyn
58. Scalable JavaScript Applications with Project Nashorn [CON6423] Project Avatar: Server-Side JavaScript on the JVM [CON5675] 1 2 3 javaone 2014 taks to catch up Project Avatar: More Than Just Node.js on the JVM—Java EE Written in JavaScript [CON4091] 4 Toward Native JavaScript Performance on the JVM [CON4679]
59. Q& A
60. SHOW ME THE CODE https://github.com/gAmUssA/java-scripting-experiments
61. THANKS FOR YOUR ATTENTION www.faratasystems.com // follow me : twitter.com/gamussa