JavaからScalaへ

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1 #01 Java Scala (NISHIMOTO Keisuke)

2 Java #01 Java Scala 2

3 (NISHIMOTO Keisuke) (follow,remove,block ) Java Scala Web GUI/ #01 Java Scala 3

4 29 Ruby/Rails Scala on JRuby by keisuken -2 Web Go! ( ) #01 Java Scala 4

5 What is Scala? ( ) Scala is a general purpose programming language designed to express common programming patterns in a concise, elegant, and type-safe way. It smoothly integrates features of object-oriented and functional languages. It is also fully interoperable with Java. Scala Java #01 Java Scala 5

6 Scala * EPFL( ) Java 5 (JRE/JDK) JavaME CLDC/Android.Net : Scala Lisence (BSD-style Lisence) #01 Java Scala 6

7 ( ) #01 Java Scala 7

8 * (4-5 ) 2 Java.NET(CLR) Java C# / (JAR, EXE) #01 Java Scala 8

9 Scala, etc. etc. #01 Java Scala 9

10 Scala etc. immutable : val immutable : scala.collection.immutable._ #01 Java Scala 10

11 Wikipedia #01 Java Scala 11

12 Haskell, Clean F#, ML, OCaml, Scala Erlang, Lisp, Scheme #01 Java Scala 12

13 ( ) / #01 Java Scala 13

14 * scala / scalac fsc : Java scalac : scaladoc sbaz API : javadoc Scala #01 Java Scala 14

15 *,,,, 1234, true/false, 'c', "Hello, world!", 'id XML val title = "Hello, world!" val html = <html> <head><title>{title}</title></head> <body>{title}</body> </html> #01 Java Scala 15

16 * (Java ) class Java class object Singleton class 1 Java static method/field main #01 Java Scala 16

17 * (Java ) trait Java interface class Mix-in #01 Java Scala 17

18 * val func = {(x: Int, y: Int) => x + y} println(func(1, 2)) // 3 def add(x: Int)(y: Int) = x + y val add1234 = add(1234) _ val result = add1234(5678) println(result) // 6912 #01 Java Scala 18

19 Structural typing Generics Annotations Implicit Parameters Implicit Conversions etc...etc... #01 Java Scala 19

20 Hello, world! (Java) * // Hello, world package examples; public class HelloWorld { public static void main(string[] args) { System.out.println("Hello, world!"); } } #01 Java Scala 20

21 Hello, world! (Scala) // Hello, world package examples * object HelloWorld { def main(args: Array[String]) { println("hello, world!") } } #01 Java Scala 21

22 Foo class (Java) public class Foo { } private String name; public Foo(String name) { } this.name = name; * public void name(string name) { } this.name = name; public String name() { } return name; #01 Java Scala 22

23 * Foo class (Scala) class Foo(var name: String) #01 Java Scala 23

24 * trait trait Name { def name def length = name.length } class SmithName extends Name { def name = "Smith" } println((new SmithName).length) // 5 #01 Java Scala 24

25 * Java String str = "Hello, world!"; int i = 1234; int[] values = new int[] {1, 2, 3}; Scala val str = "Hello, world!" val i = 1234 val values = Array(1, 2, 3) #01 Java Scala 25

26 Implicit Conversions * : // str: java.lang.string val str = "1234" // toint val length = str.toint // 1234 #01 Java Scala 26

27 Implicit Conversions class Person(name: String) * class RichPerson(person: Person) { def splitname = person.name.split("[ s]+") } implicit def psn2rpsn(person: Person) = new RichPerson(person) val person = new Person("Foo Boo Bar") println(person.splitname) // Array("Foo", "Boo", "Bar") #01 Java Scala 27

28 * ( ) switch case ( ) #01 Java Scala 28

29 (Java) Object value = new Integer(1234); String message; if (value instanceof Integer) { message = "Int: " + value; } else if (value instanceof String) { message = "String: " + value; } else { message = "Not match"; } #01 Java Scala 29

30 * (Scala) val value: Any = 1234 val message = value match { case i: Int => "Int: " + i case s: String => "String: " + s case _ => "Not match" } // "Int: 1234" #01 Java Scala 30

31 * val regex = """ s*([0-9]+) s*/ s*([0-9]+) s*""".r val (n1, n2) = " 123 / 456 " match { case regex(n1, n2) => (n1.toint, n2.toint) case _ => (0, 0) } // (123, 456) #01 Java Scala 31

32 Java (JDK/JRE) JAVA_HOME #01 Java Scala 32

33 Scala scala final.tar.gz(or.zip)» SCALA_HOME( )» PATH $SCALA_HOME/bin IzPack Java Installer MacPorts(Mac OS X) #01 Java Scala 33

34 * bash-3.2$ scala Welcome to Scala version final scala> for (i <- 1 to 4) { println(i) } scala> #01 Java Scala 34

35 * (HelloWorld.scala) object HelloWorld { def main(args: String) { println("hello, world!") } } bash-3.2$ scalac HelloWorld.scala bash-3.2$ scala HelloWorld Hello, world! #01 Java Scala 35

36 IDE Eclipse Eclipse 3.4 Classic Eclipse Scala Plug-in #01 Java Scala 36

37 IDE NetBeans NetBeans 6.5 nightly build NetBeans Scala Plug-in #01 Java Scala 37

38 * Scala Array(1, 2, 3) Actor Parser Combinator XML etc Java API #01 Java Scala 38

39 Scalax The Scala Community Library Scala/xml Jiva XQery, XSLT Genetic Algorithms (GA) toolkit Scala-rel, scala.dbc ORM/SQL #01 Java Scala 39

40 ScalaCheck QuickCheck( Haskell) Scala. Rehersal SUnit (Sunit ) ScalaTest OSS (Scala/Java). Specs BDD(Behavior-Driven-Design) RSpec #01 Java Scala 40

41 lift Web Framework * Java Servlet Rails/Django Scala XML View Actor (Comet ) ORM #01 Java Scala 41

42 Web Flavor * Servlet Web ( ) Scala Servlet API XML View Administrator menu Web keisuken( ) #01 Java Scala 42

43 Web Flavor >>1 Web Flavor Java Scala #01 Java Scala 43

44 Web Flavor DRY: Don't Repeat Youreself: CoC: Convention Over Configuration #01 Java Scala 44

45 *Web Flavor Hello, world! // HelloWorld.scala val TITLE = "Hello, world!" <html> <head><title>{title}</title></head> <body><h1>{title}</h1></body> </html> #01 Java Scala 45

46 *Web Flavor HelloWorldPOHP  <html> <head><title><span flavor:id="title"/></title></head> <body> <h1><span flavor:id="title"/></h1> <p><span flavor:id="message"/></p> </body> </html> // HelloWorldPOHP.scala Template("", "title" -> Text("Hello, world!"), "message" -> <strong>web Flavor world!</strong> ) #01 Java Scala 46

47 Web Flavor PrintRequestParameters // PrintRequestParameters.scala val TITLE = "PrintRequestParameters" <html> <head><title>{title}</title></head> <body> <h1>{title}</h1> <dl>{ for ((name, value) <- params) yield <dt>{name}</dt><dd>{value}</dd> }</dl> </body> </html> #01 Java Scala 47

48 Web Flavor ORM GUI Locale POHP #01 Java Scala 48

49 *Java Java 1 Java Scripting Framework Java Scala, Scala Java (Jar ) #01 Java Scala 49

50 *Java Java /JAR scalac Java JAR/WAR/EAR Java scala-library.jar(scala ) CLASSPATH Java #01 Java Scala 50

51 Java Java API/ Scala import javax.swing._ val frame = new JFrame("Foo")... frame.setvisible(true) Java Generics Scala import java.util._ val list = new ArrayList[String] list.add("abc")... #01 Java Scala 51

52 Java Scala Java Scala: def name_=(value: String) { } Java: void name_$eq(string value) { } object $ Function{ }[, ] Generics Scala Java #01 Java Scala 52

53 Java * Java? 1 ( ) Java Scala Java #01 Java Scala 53

54 Scala * Java? Java / #01 Java Scala 54

55 Eclipse Scala Plug-in WebFlavor #01 Java Scala 55

56 Scala Scala Wiki Scala Blog #01 Java Scala 56

57 Lingr - Scala-ja Scala-sandbox (CodeRepos) mixi - Scala lift Web Framework Web Flavor #01 Java Scala 57

58 Any Questions? #01 Java Scala 58

10/ / /30 3. ( ) 11/ 6 4. UNIX + C socket 11/13 5. ( ) C 11/20 6. http, CGI Perl 11/27 7. ( ) Perl 12/ 4 8. Windows Winsock 12/11 9. JAV

10/ / /30 3. ( ) 11/ 6 4. UNIX + C socket 11/13 5. ( ) C 11/20 6. http, CGI Perl 11/27 7. ( ) Perl 12/ 4 8. Windows Winsock 12/11 9. JAV tutimura@mist.i.u-tokyo.ac.jp kaneko@ipl.t.u-tokyo.ac.jp http://www.misojiro.t.u-tokyo.ac.jp/ tutimura/sem3/ 2002 12 11 p.1/33 10/16 1. 10/23 2. 10/30 3. ( ) 11/ 6 4. UNIX + C socket 11/13 5. ( ) C 11/20