Decorator pattern for Kotlin ReadWriteProperties

decorate.kt

private fun <ThisRef, Value> ReadWriteProperty<ThisRef, Value>.decorate(): ReadWriteProperty<ThisRef, Value?> {
    return DecoratorExample(this)
}

class DecoratorExample<in ThisRef, Value>(val decorated: ReadWriteProperty<ThisRef, Value>) : ReadWriteProperty<ThisRef,
        Value?> {
    override fun getValue(t: ThisRef, property: KProperty<*>): Value {
        return decorated.getValue(t, property)
    }

    override fun setValue(thisRef: ThisRef, property: KProperty<*>, value: Value?) {
        value?.also { decorated.setValue(thisRef, property, it) }
    }
}

class SomeStringProperty : ReadWriteProperty<Any?,String> {

    private var x: String = ""

    override fun getValue(t: Any?, property: KProperty<*>): String {
        return x
    }

    override fun setValue(t: Any?, property: KProperty<*>, value: String) {
        x = value
    }
}