generics.kt

package aaa

import kotlin.reflect.KClass
import kotlin.reflect.full.createInstance

//open class Mammal(override val name: String) : Named
//class Cat(name: String) : Mammal(name)
//
//class List {
//    fun get(n : Int) : Any? { return null}
//    fun add(item : Any) {}
//}
//class CatList {
//    fun get(n: Int): Cat? {
//        return null
//    }
//
//    fun add(item: Cat) {}
//}
//class MammalList {
//    fun get(n : Int) : Mammal? { return null}
//    fun add(item : Mammal) {}
//}
//
//fun listTest() {
//    val list = List()
//    list.add(Cat())
//    list.add(Mammal())
//    val cat = list.get(0)
//    cat as Cat
//}
//
//class GenericList<ITEM> {
//    fun get(n : Int) : ITEM? { return null}
//    fun add(item : ITEM) {}
//}
//fun listTest2() {
//    val catList = GenericList<Cat>()
//    val mammalList = GenericList<Mammal>()
//    catList.add(Cat())
//    mammalList.add(Mammal())
//    val cat = catList.get(0)
//    cat
//}
//fun vars1() {
//    var list : GenericList<Mammal>? = null
//    val catList = GenericList<Cat>()
//    val mammalList = GenericList<Mammal>()
//    list = mammalList
//    list = catList
//}
//
//class NamedGenericList<ITEM : Named> {
//    fun get(n : Int) : ITEM? { return null}
//    fun add(item : ITEM) {}
//    fun getName(n : Int) : String? {return get(n)?.name}
//}
//
//
interface Named {
    var name : String?
}
//
//class List2<ITEM> {
//    val data = mutableListOf<ITEM>()
//    fun get(n : Int) : ITEM = data[n]
//    fun add(item : ITEM) {data.add(item)}
//}
//
//interface Source<out ITEM> {
//    fun next() : ITEM
//}
//
//
//
//fun sourceTest1(cats : Source<Cat>) {
//    val objects : Source<Any> = cats
//    val mammals : Source<Mammal> = cats
//    val cats2 : Source<Cat> = cats
//}
//fun sourceTest2(mammals : Source<Mammal>) {
//    val objects : Source<Any> = mammals
//    val mammals2 : Source<Mammal> = mammals
//    val cat : Source<Cat> = mammals
//}
//class Transporter<in ITEM> {
//    fun transport(item : ITEM) {}
////    fun get() : ITEM? {return null}
//}
//fun transportTestUser() {
//    transportTest(Transporter<Mammal>())
//}
//fun transportTest(transporter: Transporter<Cat>) {
//    transporter.transport(Cat("chewy"))
//}
//fun transportTest() {
//    var mammalTransporter : Transporter<Mammal>? = null
//    var catTransporter : Transporter<Cat>? = null
//    var anyTransporter : Transporter<Any>? = null
//
////    {
//        catTransporter = anyTransporter
//        mammalTransporter = anyTransporter
//        catTransporter = mammalTransporter
//        mammalTransporter = anyTransporter
////    }
////    {
////        anyTransporter = catTransporter
////    }
//}
//
//fun <T> copy(from : List2<out T>, to : List2<in T>) {
////    from.add("")
////    val n = to.get(1)
////    n
//}
//
//fun <FROM : TO, TO> copy2(from : List2<FROM>, to : List2<TO>) {
////    from.add("")
////    val n = to.get(1)
////    n
//}
//
//fun copyTest() {
//    val catList1 = List2<Cat>()
//    val catList2 = List2<Cat>()
//    val mammalList = List2<Mammal>()
//
//    copy(catList1, catList2)
//    copy(catList1, mammalList)
//    copy2(catList1, mammalList)
//}
//
//interface Source2<out T> {
//    fun next() : T
//}
//interface Source3<out T : Mammal> {
//    fun next() : T
//}
//interface Transporter2<in T> {
//    fun transport(item : T)
//}
//interface Transporter3<in T : Mammal> {
//    fun transport(item : T)
//}
//
//fun starTest(source : Source2<*>) {
//    var a = source.next()
//    a
//}
//fun starTest2(source : Source3<*>) {
//    var a = source.next()
//    a
//}
//fun starTest3(transporter: Transporter2<*>) {
//    transporter.transport(null)
//}
//fun starTest4(transporter: Transporter3<*>) {
//    transporter.transport(null)
//}
//fun starTest4(list : List2<*>) {
//    val n = list.get(0)
//    n
//    list.add("")
//}

open class ItineraryItem(val name : String, vararg val subItems : ItineraryItem) {
    var parent : ItineraryItem? = null
    init {
        for(item in subItems) {
            item.parent = this
        }
    }
}

class Trip(name : String, vararg subItems: ItineraryItem) : ItineraryItem(name, *subItems)
class City(name : String, vararg subItems: ItineraryItem) : ItineraryItem(name, *subItems)
class Hotel(name : String, vararg subItems: ItineraryItem) : ItineraryItem(name, *subItems)
class Car(name : String, vararg subItems: ItineraryItem) : ItineraryItem(name, *subItems)

fun <T:Any> parentOfType(type : KClass<T>, item :ItineraryItem) : T? {
    var temp : ItineraryItem? = item
    while (temp != null) {
        if (type.isInstance(temp)) {
            return temp as T
        }
        temp = temp.parent
    }
    return null
}

inline fun <reified T:Any> parentOfType2(item :ItineraryItem) : T? {
    var temp : ItineraryItem? = item
    while (temp != null) {
        if (temp is T) {
            return temp
        }
        temp = temp.parent
    }
    return null
}

inline fun <reified T : Named> create(name : String) : T {
    return T::class.createInstance().apply { this.name = name }
}

class Person : Named {
    override var name: String? = null
}

fun main(args : Array<String>) {
    val hotel = Hotel("Doubletree")
    val car = Car("National")
    val city = City("Portland", hotel, car)
    val trip = Trip("Visit Trevor", city)

    val city2 = parentOfType(City::class, hotel)
    println(city2?.name)
    val city3 = parentOfType2<City>(hotel)
    println(city3?.name)

    create<Person>("Scott")
}