/*
* Static and dynamic method dispatch in Kotlin
* Functions defined (and overridden) have dynamic dispatch
* The function called is dependent on the class of the
* underlying object at the time it was created, regardless
* of what is has been cast to
*
* Extension functions have static dispatch.
* The function called is dependent on the type visible at the 
* time of the call.  
* Also, if there is a member funtion and an extension function 
* of the same name, the member wins!
*
*@author gtowell
* created: Aug 5, 2021
 */

// a class
open class Shape
// an inheriting class
class Rectangle: Shape()
// extension functions for each
fun Shape.getName() = "Shape"
fun Rectangle.getName() = "Rectangle"


open class Shape2 {
    val qq = "QQ"
    open fun getName() = "Shape2"
    fun getName2() = "Shape2"
}
class Rectangle2: Shape2() {
    override fun getName() = "Rectangle2"
}
fun Shape2.getName2() = "ExtnName2"

fun Shape2.getName3() = "ExtnName3 " + this.qq + " " + this.javaClass.simpleName 

var Shape2.extensionProperty : Int
    get() = extensionProperty * extensionProperty
    set(v:Int) { extensionProperty = v }

fun main() {
    // static method dispatch for extension functions
    val r = Rectangle()
    println(r.getName())
    val s : Shape = r 
    println(s.getName())

    // dynamic method dispatch for member functions
    val r2 = Rectangle2()
    println(r.getName())
    val s2 : Shape2 = r2 
    println(s2.getName())
    // the member function wins agains the extension function
    println(s2.getName2())
    println(r2.getName2())

    // extension functions are inherited; but note that static
    // dispatch of the method does NOT mean that method calls made
    // inside the function have static dispatch!!
    val r3 = Rectangle2()
    val s3 = Shape2()
    println(r3.getName3())
    println(s3.getName3())

}