Next Generation Java - eXXcellent solutions · 2015-02-10 · Ein BLick auf die .NET Plattform l l – – l – – – – – 6 | Next Generation JVM Languages

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

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

http://www.sxc.hu/photo/36128

Disclaimer

Next Generation JVM Languages 2 |

Java

Überblick


3.

Überblick


3.

Ist Java das neue Cobol?

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Next Generation JVM Languages 5 | http://www.sxc.hu/photo/1389360

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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Überblick


Warum neue JVM Sprachen?



Beginning Buzz-Word Bingo….

http://www.sxc.hu/photo/377913



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;

}

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 #1 Quicksort


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


OOP

Sammlung von Objekten

Zustandsbehaftet

Iterativ

Imperativer Ablauf

F P

Sammlung von Funktionen

Zustandlos & Unveränderlich

Rekursiv

Auswertung: Lazy



Dynamic Typing

Next Generation JVM Languages 19 | Practically Groovy: Building, parsing, and slurping XML

http://www.ibm.com/developerworks/java/library/j-pg05199/

Parsen und

Auflisten der Daten

import org.xml.sax.SAXException;

import org.w3c.dom.*;

import javax.xml.parsers.*;

import 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();

}

}

}

Dynamic Typing



Parsen und

Auflisten der

Daten

def langs = new XmlParser().parse("languages.xml")

println "type = ${langs.attribute("type")}"

langs.language.each{

println it.text()

}

Dynamic Typing



Parsen und

Auflisten der

Daten



List<String> languages = new LinkedList<String>();

languages.add("Java");

languages.add("Ruby");

languages.add("Python");

languages.add("Perl");

Schlankere Syntax : Listen befüllen



stuff = []

stuff << "Java", "Ruby", "Python"

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;

}

}

Schlankere Syntax : Getter/Setter



class Circle

attr_accessor :center, :radius

end





java.lang.NullPointerException at com.sun.tools.javac.comp.Check.checkCompatibleConcretes(Check.java:1141)

at com.sun.tools.javac.comp.Check.checkCompatibleSupertypes(Check.java:1495)

at com.sun.tools.javac.comp.Attr.attribClassBody(Attr.java:2451)

at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:2406)

at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:2355)

at com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:444)

at com.sun.tools.javac.main.Main.compile(Main.java:592)

at com.sun.tools.javac.main.Main.compile(Main.java:544)

at com.sun.tools.javac.Main.compile(Main.java:67)

at 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

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



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

[…] 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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[...] 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 precisely-

specified interactions.

http://en.wikipedia.org/wiki/Programming_in_the_large_and_programming_in_the_small

Sprachen im industriellen Einsatz

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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/ .

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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Scala & Ko-/Kontravarianz


TL;DR Too long; didn‘t read

Scala im Portrait


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Scala - Implicit Conversion


object MainClass {

def main(args: Array[String]) {

val b : B = new A()

}

}

object A {

implicit def aToB(a: A) : B = {

new B()

}

}


Pattern Matching = Switch/Instanceof++


Beherrschbarkeit?


http://bit.ly/LP2Spb

Erfahrungen

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Erfahrungen

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JVM Sprachen im Überblick (Features)


Scala Summary

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Fantom

Fantom : Portabilität

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„one portable system, graphics, and widget library

that just works everywhere”

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

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„Ceylon’s goal is to design the language that Java would have been

if its designers had been able to predict the future.”

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

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“General-purpose language intended for industrial use”

Kotlin = Java++ bzw. Scala--

Kotlin Motivation & Hintergrund

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“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.”


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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3.

Überblick


Blick über den Tellerrand

Next Generation JVM Languages 93 | http://www.sxc.hu/photo/1167119/

Resumee


Anforderungen für den Industriellen Einsatz

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Wertung JVM Sprachen für den Industrie-Einsatz


Resumée

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Resumée

Next Generation JVM Languages 99 | Autor: woodleywonderworks

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

Weiterführende Information

[email protected]

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-for-

better-java_9066.html

http://www.scala-lang.org/



http://ceylon-lang.org/



http://blog.jetbrains.com/kotlin/

http://kotlin-demo.jetbrains.com/



http://fantom.org/sidewalk/topic/1581

http://gosu-lang.org/



http://blog.joda.org/2011/07/kotlin-and-search-for-better-java_9066.html











Documents

Next Generation Java - eXXcellent solutions · 2015-02-10 · Ein BLick auf die .NET Plattform l l – – l – – – – – 6 | Next Generation JVM Languages