Next Generation Java - Ceylon, Kotlin, Scala & Fantom im Überblick

Next Generation Java
Ceylon, Kotlin, Scala & Fantom im Überblick

Autor: dogmadic : http://www.sxc.hu/photo/436457
http://www.sxc.hu/photo/36128

Disclaimer

Java

2 | Next Generation JVM Languages

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3.

Ist Java das neue Cobol?

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Ein BLick auf die .NET Plattform

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The JVM at a glance

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Das Java- Universum

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3.

Warum neue JVM Sprachen?


Beginning Buzz-Word Bingo….



Von Lambdas und „1. Klasse“-Rechnen


Imperativ vs. Funktional: Beispiel #1 Quicksort
public void quicksort(int array[]) {
quicksort(array, 0, array.length - 1);
}
public void quicksort(int array[], int start, int end){
int i = start;
int k = end;
if (end - start >= 1) {
int pivot = array[start];
while (k > i) {
while (array[i] <= pivot && i <= end && k > i) i++;
while (array[k] > pivot && k >= start && k >= i) k--;
if (k > i) swap(array, i, k);
}
swap(array, start, k);
quicksort(array, start, k - 1);
quicksort(array, k + 1, end);
} else {
return;
}
}
public void swap(int array[], int index1, int index2) {
int temp = array[index1];
array[index1] = array[index2];
array[index2] = temp;
}


Imperativ vs. Funktional: Beispiel #2
int sum = 0;
for (int i = 0; i < 150; i++)
{
if (i % 5 != 0)
sum += i;
}

int sum = Enumerable.Range(0, 150).Where(i => i % 5 != 0).Sum();
f1(


f2(

f3(

f4())))

Objektorientierte vs. Funktionale Programmierung

FP
Sammlung von Funktionen
Zustandlos & Unveränderlich
Rekursiv
Auswertung: Lazy

OOP
Sammlung von Objekten
Zustandsbehaftet
Iterativ
Imperativer Ablauf

Dynamic Typing

Parsen und
Auflisten der Daten

Practically Groovy: Building, parsing, and slurping XML
http://www.ibm.com/developerworks/java/library/j-pg05199/

Dynamic Typing
import
import
import
import

org.xml.sax.SAXException;
org.w3c.dom.*;
javax.xml.parsers.*;
java.io.IOException;

public class ParseXml {
public static void main(String[] args) {
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
try {
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse("src/languages.xml");
//print the "type" attribute
Element langs = doc.getDocumentElement();
System.out.println("type = " + langs.getAttribute("type"));
//print the "language" elements
NodeList list = langs.getElementsByTagName("language");
for(int i = 0 ; i < list.getLength();i++) {
Element language = (Element) list.item(i);
System.out.println(language.getTextContent());
}
}catch(ParserConfigurationException pce) {
pce.printStackTrace();
}catch(SAXException se) {
se.printStackTrace();
}catch(IOException ioe) {
ioe.printStackTrace();
}
}
}

Parsen und
Auflisten der
Daten

Dynamic Typing

def langs = new XmlParser().parse("languages.xml")
println "type = ${langs.attribute("type")}"
langs.language.each{
println it.text()
}

Parsen und
Auflisten der
Daten


Schlankere Syntax : Listen befüllen
List<String> languages = new LinkedList<String>();
languages.add("Java");
languages.add("Ruby");
languages.add("Python");
languages.add("Perl");

stuff = []
stuff << "Java", "Ruby", "Python"



Schlankere Syntax : Getter/Setter
Class Circle
private Coordinate center, float radius;
public void setCenter(Coordinate center){
this.center = center;
}
public Coordinate getCenter(){
return center;
}
public void setRadius(float radius){
this.radius = radius;
}
public Coordinate getRadius(){
return radius;
}
}

class Circle
attr_accessor :center, :radius
end



java.lang.NullPointerException
at
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com.sun.tools.javac.comp.Check.checkCompatibleConcretes(Check.java:1141)
com.sun.tools.javac.comp.Check.checkCompatibleSupertypes(Check.java:1495)
com.sun.tools.javac.comp.Attr.attribClassBody(Attr.java:2451)
com.sun.tools.javac.comp.Attr.attribClass(Attr.java:2406)
com.sun.tools.javac.comp.Attr.attribClass(Attr.java:2355)
com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:444)
com.sun.tools.javac.main.Main.compile(Main.java:592)
com.sun.tools.javac.main.Main.compile(Main.java:544)
com.sun.tools.javac.Main.compile(Main.java:67)
com.sun.tools.javac.Main.main(Main.java:52)


Die Null zügeln

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Domain Specific Languages

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Alternativen zur Threads & Co.

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Scripting

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Meta-Programmierung
Programmen, die sich oder andere P. als Daten behandeln und verändert.

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Dynamic & Weak Typing

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“A programming language is said to be dynamically typed when the majority
of its type checking is performed at run-time as opposed to at compile-time.
In dynamic typing values have types, but variables do not […]”
https://en.wikipedia.org/wiki/Dynamic_typing#Dynamic_typing

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[…] strong typing when it specifies one or more restrictions on how operations
involving values of different data types can be intermixed.
Weak typing means that a language implicitly converts (or casts) types when used.
https://en.wikipedia.org/wiki/Dynamic_typing#Dynamic_typing


Überblick

3.

Auszug neuer JVM Sprachen

Inzwischen über 50-250 verschiedene Sprachen auf der JVM…

Anforderungen für den Industriellen Einsatz

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Sprachen im industriellen Einsatz

[...] programming by larger groups of people or by smaller groups over
longer time periods [...] result in large, and hence complicated, programs
[...] place emphasis on partitioning work into modules with preciselyspecified interactions.
http://en.wikipedia.org/wiki/Programming_in_the_large_and_programming_in_the_small

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Auszug neuer JVM Sprachen


Übersicht & Entwicklung JVM Sprachen


Statisch-typisierte JVM Sprachen im Überblick



http://www.flickr.com/photos/tonino62/2295302323/

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Scala im Portrait

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Scala im Portrait

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Traits & Mixins

trait Similarity {
def isSimilar(x: Any): Boolean
def isNotSimilar(x: Any): Boolean = !isSimilar(x)
}


Extension Methods

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TL;DR
Too long; didn‘t read

Scala & Ko-/Kontravarianz


Scala im Portrait

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Scala - Implicit Conversion

object A {
implicit def aToB(a: A) : B = {
new B()
}
}


object MainClass {
def main(args: Array[String]) {
val b : B = new A()
}
}

Pattern Matching = Switch/Instanceof++


Beherrschbarkeit?
http://bit.ly/LP2Spb


Erfahrungen

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Erfahrungen

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JVM Sprachen im Überblick (Features)

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Scala Summary

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Fantom



Fantom : Portabilität

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„one portable system, graphics, and widget library
that just works everywhere”

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Fantom im Portrait

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Fantom : Quadratur der Kreise

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obj.methode()
obj->methode()

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Fantom : Multi-Threading

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Fantom : Elegante APIs und Sprache

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Fantom Hello World (Webapp)
using util
using web
using wisp
class WebHello : AbstractMain
{
@Opt { help = "http port" }
Int port := 8080
override Int run()
{
wisp := WispService
{
it.port = this.port
it.root = HelloMod()
}
return runServices([wisp])
}
}


const class HelloMod : WebMod
{
override Void onGet()
{
res.headers["Content-Type"] =
"text/plain; charset=utf-8"
res.out.print("hello world #4")
}
}

Fantom: Summary

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http://bit.ly/LKM5YG


Ceylon im Portrait
„Ceylon’s goal is to design the language that Java would have been
if its designers had been able to predict the future.”

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Ceylon: Code Example
doc "A component"
shared abstract class Component() {
OpenList<Callable<Void,Event>> observers =
OpenList<Callable<Void,Event>>();
shared void addObserver(void observe(Event event)) {
observers.append(observe);
}
shared void fire(Event event) {
for (void observe(Event event) in observers) {
observe(event);
}
}
}


…bisschen Spannendes hat Ceylon aber schon…

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Nullables


Von Typen mit und ohne Charakter


Ceylon: Summary

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Kotlin im Portrait
“General-purpose language intended for industrial use”
Kotlin = Java++ bzw. Scala--

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Kotlin Motivation & Hintergrund

“Although we’ve developed support for several JVM-targeted programming languages,
we are still writing all of our IntelliJ-based IDEs almost entirely in Java.
We want to become more productive by switching to a more expressive language.”

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Kotlin Sprach-Features

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interface Collection<E> ... {
void addAll(Collection<? extends E> items);
}

abstract class Source<out T> {
fun nextT() : T
}
fun fill(dest : Array<in String>, value : String) {
// ...
}


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Kotlin: Online Demo


Kotlin Summary:

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Überblick

3.

Blick über den Tellerrand


http://www.sxc.hu/photo/1167119/

Resumee



Anforderungen für den Industriellen Einsatz

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Wertung JVM Sprachen für den Industrie-Einsatz

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Resumée

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Resumée


Weiterführende Information
Benjamin.Schmid@exxcellent.de
Scala: http://www.scala-lang.org/
Ceylon: http://ceylon-lang.org/
Kotlin: http://blog.jetbrains.com/kotlin/
Kotlin Demo: http://kotlin-demo.jetbrains.com/
Fantom vs. Kotlin http://fantom.org/sidewalk/topic/1581

Gosu: http://gosu-lang.org/
Search for a better Java:
http://blog.joda.org/2011/07/kotlin-and-search-forbetter-java_9066.html

Autor: woodleywonderworks
http://www.flickr.com/photos/wwworks/4759535950/

Next Generation Java - Ceylon, Kotlin, Scala & Fantom im Überblick

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