Descubra as capacidades do novo motor de Javascript, Nashorn, presente no Java SE 8

1. Nashorn: novo motor
Javascript no Java 8
Bruno Borges
Principal Product Manager
Java Evangelist

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• Java Evangelist
• Orale Product Manager
• Entusiasta JavaFX e IoT
• Onde me encontrar
• @brunoborges
• plus.google.com/+BrunoBorges
Bruno Borges

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Agenda
• Nashorn Overview
• Nashorn e Java
• Nashorn usando o comando jjs
• Shell Scripting com Nashorn
• Nashorn e JavaFX

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Nashorn Overview
• Runtime Java baseado na linguagem Javascript
• ECMAScript 262 v5.1
• Familar para desenvolvedores de conteúdo
• Permite uso de uma série de bibliotecas e ferramentas escritas em
Javascript
• Node.JS
• Obtém todas as vantagens das tecnologias Java
Scripting for Java

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Nashorn Overview
• Forte integração com a plataforma Java
• Extensões foram adicionadas para prover acesso ao Java
• Nashorn pode ser usado no Java usando a ScriptEngine API
• Nashorn pode também ser usado pela linha de comando jjs
• Suporte para shell scripting
• Suporte completo ao JavaFX
• NetBeans 8 suporta desenvolvimento com Nashorn
Funcionalidades

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NASHORN E JAVA

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Nashorn e Java
import javax.script.*;
public class Main {
public static void main(String[] args) {
final ScriptEngineManager manager = new ScriptEngineManager();
final ScriptEngine engine = manager.getEngineByName("nashorn");
try {
engine.eval("print('hello world');");
} catch (final ScriptException se) {
System.err.println(se);
}
}
}
Exemplo 1

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Nashorn e Java
String script = "var x = 10;n" +
"var y = 20;n" +
"var z = x + y;n" +
"z;n";
Object result = engine.eval(script);
int value = (Integer)result;
System.out.println(value);
Exemplo 2

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Nashorn e Java
engine.put("x", 100);
engine.put("y", 200);
engine.eval("var z = x + y;");
int value = (Integer)engine.get("z");
System.out.println(value);
Exemplo 3

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Nashorn e Java
var HashMap = java.util.HashMap;
var map = new HashMap();
map.put("apple", "red");
map.put("bear", "brown");
map.put("canary", "yellow");
print("A bear is " + map.get("bear"));
for (var key in map) print("key: " + key);
for each (var value in map) print("value: " + value);
Exemplo 4

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NASHORN
USANDO JJS

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Nashorn usando jjs
• Nashorn pode ser chamado usando a ferramenta jjs por linha de
comando
• Facilita o uso de Javascript no dia-a-dia
• Tarefas rápidas
• Prototipação
• Experimento com novas features do Java
• Shell scripts
A partir da linha de comando

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Nashorn usando jjs
>> where jjs
/usr/bin/jjs
>> jjs
jjs> var x = 10;
jjs> var y = 20;
jjs> print(x + y);
30
jjs> quit();
>>
Exemplo 5

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Nashorn usando jjs
Exemplo 6

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SHELL SCRIPTING
COM NASHORN

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Shell Scripting com Nashorn
• Por que não utilizar uma linguagem que você já está familiarizado?
• Acesso a um vasto número de bibliotecas Java
• Extensões de scripting para simplificar
• Documentos
• Templates de Strings
• Execução de comandos
• Variáveis de ambiente
Substituto mais simples para outras linguagens shell

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Schell Scripting usando Nashorn
#!/usr/bin/jjs -doe -scripting
#
var dir = __DIR__ + "photos";
var files = `ls ${dir}`.trim().split("n");
var count = 1;
for each (var file in files) {
if (file.edsWith(".jpg")) {
`mv ${dir}/${file} ${dir}/Photo${count++}.jpg`;
}
}
Exemplo 7

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NASHORN E
JAVAFX

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Nashorn e JavaFX
• Método bem natural de trabalhar com JavaFX
• Nashorn pode ser invocado a partir de FXML
• FXML é uma opção, em formato XML, para definir interfaces em JavaFX
• Modelo familiar para desenvolvedores de conteúdo
Nashorn foi feito para o JavaFX

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Nashorn e JavaFX
load("fx:base.js");
load("fx:controls.js");
load("fx:graphics.js");
$STAGE.title = "Hello World!";
var button = new Button();
button.text = "Say 'Hello World'";
button.onAction = function() print("Hello World!");
var root = new StackPane();
root.children.add(button);
$STAGE.scene = new Scene(root, 300, 250);
$STAGE.show();
Exemplo 8

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Recapitulando
• Forte integração com Java
• Pode ser usado a partir do Java
• Nova ferramenta por linha de comando jjs
• Supore a Shell Scripting
• Suporte completo ao JavaFX

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Para saber mais
• Download: java.oracle.com
• Documentação: docs.oracle.com/javase
• Treinamentos: education.oracle.com/java
• Central do Java 8: www.oracle.com/java8
• Nashorn para Usuários
• wiki.openjdk.java.net/display/Nashorn/Nashorn+Documentation
• Exemplos: blogs.oracle.com/nashorn/
• Dúvidas: nashorn-dev@openjdk.java.net
Java 8 e outros sites
youtube.com/java
blogs.oracle.comjava
facebook.com/ilovejava
@java
@javaembedded
nighthacking.com

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