Scripting In Java

Scripting in Java

JavaLand 2014

25.03.2014, Lars Gregori

Scripting in Java

JavaLand 2014

25.03.2014, Lars Gregori

© 2014 Lars Gregori, msgGillardon AG | Scripting in Java | 25.03.2014

Lars Gregori

msgGillardon AG

CoC IT-Architekturen

learn a new language every year

--- The Pragmatic Programmer

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© 2014 Lars Gregori, msgGillardon AG | Scripting in Java | 25.03.2014 5


Was sind Scriptsprachen?

Wikipedia:

„Scriptsprachen sind Programmiersprachen, die vor allem für kleine,

überschaubare Programme gedacht sind. Sie verzichten oft auf

bestimmte Sprachelemente, deren Nutzen erst bei der Bearbeitung

größerer Projekte zum Tragen kommen. So wird etwa in

Skriptsprachen auf den Deklarationszwang von Variablen meist

verzichtet - vorteilhaft zur schnellen Erstellung von kleinen

Programmen (siehe auch Prototyping), bei großen hingegen von

Nachteil, etwa wegen der fehlenden Überprüfungsmöglichkeit von

Tippfehlern in Variablennamen.“

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http://de.wikipedia.org/wiki/Skriptsprache



Was sind Scriptsprachen?

Wikipedia:

„Scriptsprachen sind Programmiersprachen, die vor allem für kleine,

überschaubare Programme gedacht sind. Sie verzichten oft auf

bestimmte Sprachelemente, deren Nutzen erst bei der Bearbeitung

größerer Projekte zum Tragen kommen. So wird etwa in

Skriptsprachen auf den Deklarationszwang von Variablen meist

verzichtet - vorteilhaft zur schnellen Erstellung von kleinen

Programmen (siehe auch Prototyping), bei großen hingegen von

Nachteil, etwa wegen der fehlenden Überprüfungsmöglichkeit von

Tippfehlern in Variablennamen.“

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Static vs. Dynamic Typing

Most scripting languages are dynamically typed

explicit type declarations not required

type information is attached to values, not to variables

Java is static-typed

require variable type (declaration time)

only data of declared type

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https://confluence.deri.ie:8443/display/romulus/Scripting+Languages+and+java



Weak vs. Strong Typing

Java is a static, strongly typed language

strongest possible constraint on the type of object at declaration time

prevents mixing operations between mismatched types

Many scripting languages are weakly typed

allow operations on incompatible types

implicit type conversion or ad-hoc polymorphism

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Weak vs. Strong Typing

Java is a static, strongly typed language

strongest possible constraint on the type of object at declaration time

prevents mixing operations between mismatched types

Many scripting languages are weakly typed

allow operations on incompatible types

implicit type conversion or ad-hoc polymorphism

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Quality and Performance

Scripting languages are more compact and readable

less lines of code

weak typing not requiring the overhead of type declaration

Fewer lines of code and less complexity means lower amounts of

bugs, thus reducing development and maintenance costs.

The missing type information has some disadvantages.

static, strongly typed languages ensure the robustness

type errors will be detected at compile time

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runtime performance

extra overhead of the interpreter and runtime checks

not performed at compile time

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http://attractivechaos.github.io/plb/






runtime performance

extra overhead of the interpreter and runtime checks

not performed at compile time

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Motivation


Motivation

cool

mal etwas anderes

macht Spass

JATUMBA

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Motivation

elegant und einfach erweitern

Konfigurationsdatei

Datenbank

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Motivation

elegant und einfach erweitern

Konfigurationsdatei

Datenbank

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passender

Inner DSL

(JRuby)

String Manipulation

(Jython, Perl)

map / reduce

(Lisp, Clojure)

GroovySQL,

GroovyMarkup

Templates

Motivation

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passender

Inner DSL

(JRuby)

String Manipulation

(Jython, Perl)

map / reduce

(Lisp, Clojure)

GroovySQL,

GroovyMarkup

Templates

Motivation

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Motivation

selbe Technologie

Frontend und Backend

Javascript Validierung

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Motivation

selbe Technologie

Frontend und Backend

Javascript Validierung

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Motivation

langsamer als Java

Entwickler muss

andere Sprache lernen

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Motivation

langsamer als Java

Entwickler muss

andere Sprache lernen

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Buch

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http://www.scriptinginjava.net/

Scripting in Java:

Languages, Frameworks, and Patterns

by Dejan Bosanac

Publisher: Addison Wesley Professional

Pub Date: August 31, 2007 (est.)

Print ISBN-10: 0-321-32193-6

Print ISBN-13: 978-0-321-32193-0

eText ISBN-10: 0-321-50933-1

eText ISBN-13: 978-0-321-50933-8

Pages: 432

http://www.scriptinginjava.net/


Scriptsprachen in Java einbinden

kompilieren

eigene Engine

Bean Scripting Framework (BSF)

JSR 223 – Scripting for the Java Platform

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kompilieren – groovyc

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package my.groovy.jartest class Answer { def answer() { 42 } }

package my.groovy.jartest; import groovy.lang.GroovyObject; public class Answer implements GroovyObject { ... public Object answer() { CallSite[] arrayOfCallSite = $getCallSiteArray(); return Integer.valueOf(42); return null; } }

import my.groovy.jartest; ... Answer answer = new Answer(); int a = (Integer) answer.answer();


Script Engine

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GroovyShell gs = new GroovyShell(); String script = "return 42"; int answer = (Integer) gs.evaluate(script);

Binding binding = new Binding(); binding.setVariable("foo", new Integer(2)); GroovyShell shell = new GroovyShell(binding); Object value = shell.evaluate( "println 'Hello World!'; x = 123; return foo * 10"); assert value.equals(new Integer(20)); assert binding.getVariable("x").equals(new Integer(123)); http://groovy.codehaus.org/Embedding+Groovy

http://groovy.codehaus.org/Embedding+Groovy


Bean Scripting Framework (BSF)

http://commons.apache.org/proper/commons-bsf/

Bean Scripting Framework (BSF) is a set of Java classes which

provides scripting language support within Java applications, and

access to Java objects and methods from scripting languages.

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Bean Scripting Framework (BSF) – Beispiel

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BSFManager manager = new BSFManager(); manager.declareBean("a", 6, Integer.class); manager.declareBean("b", 7, Integer.class); String script = "var answer = a * b;" + "bsf.registerBean(\"answer\", answer)"; manager.eval("javascript", "blah", 0, 0, script); Double answer = (Double) manager.lookupBean("answer"); assertEquals(42, answer.intValue());


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JSR-223 – Scripting for the Java Platform

The specification describe mechanisms allowing scripting language

programs to access information developed in the Java Platform …

https://jcp.org/en/jsr/detail?id=223

Java 1.6+

Rhino JavaScript for Java version 1.6R2

javax.script.*

jrunscript

http://docs.oracle.com/javase/6/docs/technotes/tools/share/jrunscript.html

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http://docs.oracle.com/javase/6/docs/technotes/tools/share/jrunscript.html


ServiceLoader

Since: 1.6

http://docs.oracle.com/javase/6/docs/api/java/util/ServiceLoader.html

META-INF/services/javax.script.ScriptEngineFactory

This file contains the single line:

de.torq.clojure.jsr223.ClojureScriptEngineFactory

Clojure JSR 223 build.xml

https://github.com/pmf/clojure-jsr223/blob/master/build.xml

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<jar jarfile="${clojure_jsr223_bundle}" basedir="${build_osgi}"> <service type="javax.script.ScriptEngineFactory“ provider="de.torq.clojure.jsr223.ClojureScriptEngineFactory"/>







JSR-223 – script engines

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Beispiele

JRuby

Groovy

Clojure

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JDK 8 – Was ist neu?

Nashorn

Lambda

…

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Nashorn

JEP 174

http://openjdk.java.net/jeps/174

ECMAScript-262 Edition 5.1

http://ecma-international.org/ecma-262/5.1/

javax.script (JSR 223)

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Nashorn

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Lambda

JSR 335

Lambda Expressions for the Java Programming Language


Final Specification

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invokedynamic

JavaScript

4 + 2

4 + “hallo”

add(a, b)

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http://niklasschlimm.blogspot.de/2012/02/java-7-complete-

invokedynamic-example.html

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http://niklasschlimm.blogspot.de/2012/02/java-7-complete-invokedynamic-example.html











http://niklasschlimm.blogspot.de/2012/02/java-7-complete-

invokedynamic-example.html

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Invokedynamic – Jetzt und Zukunft?

JRuby

Groovy

groovy-indy

Clojure?

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Bytecode

Bytecode Frameworks

ASM : http://asm.ow2.org/

Javassist : http://www.csg.ci.i.u-tokyo.ac.jp/~chiba/javassist/

Jitescript : https://github.com/qmx/jitescript

…

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http://asm.ow2.org/

http://asm.ow2.org/

http://www.csg.ci.i.u-tokyo.ac.jp/~chiba/javassist/




https://github.com/qmx/jitescript

https://github.com/qmx/jitescript


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Da Vinci Machine

a multi-language renaissance

for the Java Virtual Machine architecture

http://openjdk.java.net/projects/mlvm/

dynamic invocation

continuations

tail-calls

interface injection

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Credits & making of

Fotos

Anja Gregori

Font

Chopin Script by ClaudeP

http://www.dafont.com/chopin-script.font

Eclipse Plugin

Bytecode Outline plugin for Eclipse

http://andrei.gmxhome.de/bytecode/

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Wir bedanken uns für Ihre Aufmerksamkeit!

msgGillardon AG

Robert-Bürkle-Str. 1

85737 Ismaning

> www.msg-gillardon.de


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Range Kata

http://codingdojo.org/cgi-bin/wiki.pl?KataRange

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integer range contains [2,6) contains {2,4} [2,6) doesn't contain {-1,1,6,10} getAllPoints? [2,6) allPoints = {2,3,4,5} ContainsRange? [2,5) doesn't contain [7,10) [2,5) doesn't contain [3,10) [3,5) doesn't contain [2,10) [2,10) contains [3,5] [3,5] contains [3,5)

endPoints [2,6) allPoints = {2,3,4,5} [2,6] allPoints = {2,3,4,5,6} (2,6) allPoints = {3,4,5} (2,6] allPoints = {3,4,5,6} overlapsRange [2,5) doesn't overlap with [7,10) [2,10) overlaps with [3,5) [3,5) overlaps with [3,5) [2,5) overlaps with [3,10) [3,5) overlaps with [2,10) Equals [3,5) equals [3,5) [2,10) neq [3,5) [2,5) neq [3,10) [3,5) neq [2,10)


List of freely available programming books

http://stackoverflow.com/questions/194812/list-of-freely-available-

programming-books/392926#392926

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http://stackoverflow.com/questions/194812/list-of-freely-available-programming-books/392926#392926












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http://groovy.codehaus.org/Differences+from+Java


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http://www.beanshell.org/manual/bshmanual.html


https://kenai.com/projects/jruby/pages/CallingJavaFromJRuby

https://kenai.com/projects/jruby/pages/CallingJavaFromJRuby

http://www.ruby-lang.org/en/documentation/ruby-from-other-languages/to-ruby-from-java/
















http://www.diveintopython.net/


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JSR 223:

https://code.google.com/p/clojure-jsr223/

http://clojure.org/java_interop

http://clojure.github.io/clojure/index.html

http://clojuredocs.org/quickref/Clojure Core





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http://jaskell.codehaus.org/


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http://www.amazon.de/Sleep-2-1-Manual-Raphael-Mudge/dp/143822723X











http://sleep.dashnine.org/download/sleep21manual.pdf

http://sleep.dashnine.org/download/sleep21manual.pdf

http://sleep.dashnine.org/manual/


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http://www.ulfdittmer.com/jlog/index.html

http://www.ulfdittmer.com/jlog/index.html


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Software

Scripting In Java