java 8: nashorn & avatar.js di enrico risa al jug roma

Nashorn & Avatar.jsJAVA 8

Agenda

• Nashorn Javascript Engine

• Node.js

• Avatar.js

• Project Avatar

Rhino

• Slow compared to other Javascript Engines (V8,Spidermonkey)

• Legacy Code (since 1998)

• Interpreted Code

• Non-compliant with ECMAScript (not 100%)

What is Nashorn?

• Started in 2011

• Embedded Javascript Engine

• Replacement of Rhino

• Open Source on the OpenJDK repository

• Released with JAVA 8

Possible use cases• Shell Scripting

-jjs

• Desktop app Javascript - Java Fx

• Server Side Javascript - More later

• End-User Javascript- Rule engines - Etl- Reporting Tools..more

Nashorn Features• ECMAScript-262 Edition 5.1 compliant

• JSR-292 “InvokeDynamic” (The Da Vinci Machine)

• Integrated with JSR-223 (Scripting for Java)

• Runtime Compiled to bytecode

• Small 1.5MB JAR

• Fast, 2x to 10x performance improvement

• Seamless Javascript/Java interoperability

Let’s jump to code

Simple Hello Word

Inject variable in the context

Javascript from Java

Java object

• Java.type

• Java.extend

• Java.from

• Java.to

• Java.super

Java.typeGiven a name of a Java type, returns an object representing that type in Nashorn. You can use with the new operator to create new instances of the class as well as to access static members of the class.

Java.extendJava.extend function returns a type object for a subclass of the specified Java class (or implementation of the specified interface) that acts as a script-to-Java adapter for it.

Java.fromConverts Java array/Collection to Javascript array

(Shallow copy)

Java.toConverts javascript objects into java type

Java.superUsed to invoke superclass methods

Java from Javascriptmap.js

Implementing Java Interface

NashornInterface.java

hello.js

Shell scripting

IDE Support

• IntelliJ IDEA 13.1 (Community and Ultimate Editions)

• Debugger

• Refactoring

Let’s talk about performance

http://ariya.ofilabs.com/2014/03/nashorn-the-new-rhino-on-the-block.html

esprima.org

What is Avatar.js ?

Avatar.js

• An open source project

• A server side Javascript framework for the JVM

• A mix of- Node.js event driven model - Nashorn Javascript engine - Java platform APIs

• Brings “the Node programming model, APIs and module ecosystem to the Java platform”.

Node.js

• Server side Javascript

• Based on Chrome V8 Engine

• Fast and Scalable

• Event driven, non-blocking I/O model

• Large community and adoption -NPM ~70000 packages

Node.js Programming Model• Single Threaded

• Event Loop-Callback-Non-blocking I/O

Node.js Event Loop

Avatar.js Features

• Run node applications on the JVM

• Call any Java API from JavaScript

• Support multiple event loops

• Support multiple Java threads

Avatar.js Node.js Modules

• async

• coffee-script

• connect

• express

• grunt

• mongodb

• mongoose

• mustache

• q

• redis

• socket.io

• underscore

…more

That means

Will run in Node.js as well as in JVM

Project Avatar

Project Avatar provides a JavaScript services layer zeroed in on supporting REST, WebSockets and Server-Sent Events, and a rich client side framework that assumes very minor JavaScript knowledge. The services side is focused on building data services using JavaScript, while the optional client side is entirely focused on supporting HTML5 and TSA (Thin Server Architecture).

Project Avatar• Server Side JavaScript Services Framework

• Focused on REST, WebSocket, Server Sent Event (SSE) endpoints

• Node.js event-driven programming model

• Layers on Avatar.js Node-compatible runtime

• Integrated EE features

• Multi-threading

• Javascript Domain Model

Avatar Architecture

Avatar Services

• REST

• WebSocket

• Push (SSE)

REST

GET - PUT - POST - DELETE

WebSocket

Server Side Events (SSE)

Javascript Model-Store• Javascript Api

-Javascript ORM (1:1, 1:N, M:N) -Support relational and non-relational databases

Javascript Model-store• Bind the model to the store

• Create a new Todo

Avatar Client (Optional)

• View- Declarative UI- Bundle widget (JQuery-[ui/mobile])

• Model- WS,REST,SSE,local - Autowired with Javascript Services

Avatar client exampleServer

Client

Additional Resources• http://openjdk.java.net/projects/nashorn/

• https://java.net/projects/adoptopenjdk

• http://www.infoq.com/articles/nashorn

• http://strongloop.com/strongblog/how-to-run-node-js-on-the-jvm-with-avatar-js-and-loopback/

• https://avatar.java.net/

• http://blog.eisele.net/2013/12/project-avatar-whats-in-it-for-java-ee-8.html

Thank you

Questions ?