Evolution of the class property

Evolution.kt

// EVOLUTION OF CLASS PROPERTY
// The presented code is in Kotlin, but the problem itself is not language-specific

// Client usage
fun main() {
    Evolution1().setName("Igor")
    Evolution2().name = "Igor"
    Evolution3().name = "Igor"
    Evolution4().name = "Igor"
}

// Internal implementations of "name" property
// Before setters
class Evolution1 {
    private var name: String = ""

    fun setName(name: String) {
        val changed = this.name != name
        this.name = name

        if(changed) {
            notifyValueChanged()
        }
    }

    private fun notifyValueChanged() {
        Timber.d("value changed $name")
    }
}

// Utilising setters
class Evolution2 {
    var name: String = ""
        set(value) {
            field = value
            Timber.d("value changed $value")
        }
}

// Utilizing Kotlin builtin observable delegate
class Evolution3 {
    var name by Delegates.observable("") { _, _, new ->
        Timber.d("value changed $new")
    }
}

// Utilizing custom observe delegate
class Evolution4 {
    var name by observer("") {
        Timber.d("value changed $it")
    }
}


// Generic helper delegate
private inline fun <T> observer(
    initialValue: T,
    crossinline onChange: (newValue: T) -> Unit
):
    ReadWriteProperty<Any?, T> =
    object : ObservableProperty<T>(initialValue) {
        override fun afterChange(property: KProperty<*>, oldValue: T, newValue: T) =
            onChange(newValue)
    }