Building Vaadin Applications With Pure Scala

Transcription

1 Building Vaadin Applications With Pure Scala Henri Kerola Vaadin Expert at Vaadin Ltd

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3 Vaadin is a UI framework for rich web applications

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5 java html

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11 Internet Explorer Chrome Firefox Safari Opera ios Android

12 No browser plugins Nothing to install

13 Scala

14 Scala A programming language created by Martin Odersky Runs on JVM and fully compatible with Java OO + FP

15 Statically typed Type inference val hello = "Hello World!" // type is String val hello: String = "Hello World!" var i = 3 // type is Int i = "hi!" // doesn t work

16 Compact public class Person { private final String name; private final int age; class Person(val name: String, val age: Int) public Person(String name, int age) { this.name = name; this.age = age; public String getname() { return name; public int getage() { return age;

17 Compact List<Person> persons =... List<Person> adults = new ArrayList<Person>(); for (Person person : persons) { if (person.getage() >= 18) { adults.add(person); val persons =... val adults = persons.filter(_.age >= 18)

18 OK, you can use Vaadin Framework with Scala, but...

19 class MyApplication extends Application { def init() { setmainwindow(new Window) val button = new Button("Click", new Button.ClickListener { def buttonclick(event: Button#ClickEvent) { getmainwindow.shownotification("button clicked!") ) getmainwindow.addcomponent(b)

20 Java style API Listeners as anonymous inner classes Verbose

21 Scaladin

22 Pure and compact Scala API for Vaadin Framework

23 By wrapping Vaadin API

24 Wrapping package vaadin.scala class Button extends AbstractField { val p = new com.vaadin.ui.button def disableonclick: Boolean = p.isdisableonclick def disableonclick_=(disableonclick: Boolean) = p.setdisableonclick(disableonclick) val button = new Button button.disableonclick = true val bisableonclick = button.disableonclick

25 com.vaadin.ui vaadin.scala AbstractComponent AbstractComponent AbstractField AbstractField AbstractSelect AbstractSelect Table Table

26 final Table table = new Table(); table.setsizefull(); table.setimmediate(true); table.setselectable(true); table.setcontainerdatasource(createcontainer()); table.addlistener(new ValueChangeListener() ); public void valuechange(valuechangeevent e) { System.out.println("Table" + e.getproperty() + "clicked!"); val table = new Table { table.sizefull() table.immediate = true = true table.selectionmode = SelectionMode.Single = table.valuechangelisteners container = createcontainer += { e => valuechangelisteners println("table " + e.property += { e: => ValueChangeEvent + " clicked!") => println("table " clicked!") + e.property + " clicked!")

27 val layout = new VerticalLayout { sizefull() VerticalLayout layout = new VerticalLayout(); layout.setsizefull(); final Button edit = new Button("Edit row"); final Table table = new Table(); table.setsizefull(); add(new Table { sizefull() valuechangelisteners += { edit.enabled = value.isdefined, ratio = 1) val edit = add(button("edit"), alignment = BottomRight) table.addlistener(new ValueChangeListener() public void valuechange(valuechangeevent event) { edit.setenabled(table.getvalue()!= null); ); layout.addcomponent(table); layout.setexpandratio(table, 1); layout.addcomponent(edit); layout.setcomponentalignment(edit, BOTTOM_RIGHT);

28 Example

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31 Tools Scala 2.9 (and Java) Eclipse and Scala IDE Scaladin JDD ja Vaadin 6.8.4

32 Tools SBT (Simple Build Tool) Akka

33 Questions?