Added 2016 April fool example

Author: occar421

Misc/kotlin-inotifypropertychanged/kotlin-inotifypropertychanged.iml

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+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+ <component name="NewModuleRootManager" inherit-compiler-output="true">
+ <exclude-output />
+ <content url="file://$MODULE_DIR$">
+ <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+ </content>
+ <orderEntry type="inheritedJdk" />
+ <orderEntry type="sourceFolder" forTests="false" />
+ <orderEntry type="library" name="KotlinJavaRuntime" level="project" />
+ </component>
+</module>

Misc/kotlin-inotifypropertychanged/result.txt

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+Notified AnotherProperty [MainViewModel@246b179d]
+This is additional for AnotherProperty
+Hoge Taro
+Notified fullName [MainViewModel@246b179d]
+This is additional for fullName
+Piyo Jiro
+9876
+Notified step [MainKt$main$subVm$1@25f38edc]
+12345

Misc/kotlin-inotifypropertychanged/src/EventHandler.kt

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+open class EventArgs
+
+class PropertyChangedEventArgs(val propertyName: String = "") : EventArgs()
+
+class EventHandler<TObj, TArg : EventArgs> {
+ private val handlers = arrayListOf<(EventHandler<TObj, TArg>.(TObj, TArg) -> Unit)>()
+
+ operator fun plusAssign(handler: EventHandler<TObj, TArg>.(TObj, TArg) -> Unit) {
+ handlers.add(handler);
+ }
+
+ operator fun invoke(sender: TObj, e: TArg) {
+ for (handler in handlers) {
+ handler(sender, e)
+ }
+ }
+}
+
+// public typeAlias PropertyChangedEventHandler = EventHandler<Any, PropertyChangedEventArgs>

Misc/kotlin-inotifypropertychanged/src/Main.kt

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+// -----------
+// ここからVM
+// -----------
+class MainViewModel : NotifyPropertyChanged {
+ fun Test() {
+ // do your complex job
+
+ raisePropertyChanged("AnotherProperty")
+ }
+
+ var fullName: String by PropertyChangedDelegate("Hoge Taro")
+}
+// -----------
+// ここまでVM
+// -----------
+
+fun main(args: Array<String>) {
+ val mainVm = MainViewModel()
+ val subVm = object : NotifyPropertyChanged {
+ var step: Int by PropertyChangedDelegate(9876)
+ }
+
+ mainVm.propertyChanged += { sender, e ->
+ println("Notified ${e.propertyName} [$sender]")
+ }
+ mainVm.propertyChanged += { sender, e ->
+ println("This is additional for ${e.propertyName}")
+ }
+
+ subVm.propertyChanged += { sender, e ->
+ println("Notified ${e.propertyName} [$sender]")
+ }
+
+ mainVm.Test()
+
+ println(mainVm.fullName)
+ mainVm.fullName = "Piyo Jiro"
+ println(mainVm.fullName)
+
+ println(subVm.step)
+ subVm.step = 12345
+ println(subVm.step)
+}

Misc/kotlin-inotifypropertychanged/src/NotifyPropertyChanged.kt

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+@Target(AnnotationTarget.VALUE_PARAMETER)
+annotation class CallerMemberName
+
+interface NotifyPropertyChanged {
+ val propertyChanged: EventHandler<Any, PropertyChangedEventArgs>
+ get() = eventHandlers.getOrPut(hashCode(), { EventHandler() })
+
+ fun raisePropertyChanged(@CallerMemberName propertyName: String = "") {
+ propertyChanged(this, PropertyChangedEventArgs(propertyName));
+ }
+
+ companion object {
+ private val eventHandlers: MutableMap<Int, EventHandler<Any, PropertyChangedEventArgs>> = mutableMapOf()
+ }
+}

Misc/kotlin-inotifypropertychanged/src/PropertyChangedDelegate.kt

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+import kotlin.reflect.KProperty
+
+class PropertyChangedDelegate<T>(initalValue: T) {
+ private var value: T = initalValue
+
+ operator fun getValue(thisRef: NotifyPropertyChanged, property: KProperty<*>): T {
+ return value
+ }
+
+ operator fun setValue(thisRef: NotifyPropertyChanged, property: KProperty<*>, value: T) {
+ this.value = value
+
+ thisRef.raisePropertyChanged(property.name)
+ }
+}