I'm trying to implement the JavaFX Property interface with a delegated Kotlin property, so that it can be used like so:

class Foo(bar:Bar){
    val barProperty=PropertyFX(bar)
    var bar by barProperty
}

I wrote up a small class for this that works (mostly):

class PropertyFX<T>(value:T):SimpleObjectProperty<T>(value),ReadWriteProperty<Any?,T>{
    override fun getValue(thisRef:Any?,property:KProperty<*>)=get()
    override fun setValue(thisRef:Any?,property:KProperty<*>,value:T)=set(value)
}

However, this class doesn't implement the interface's getBean() and getName() methods. They should return the values thisRef and property.name, respectively, from the arguments referenced in the getValue() and setValue() functions, but I don't have access to those arguments from outside the functions.

I could store the values the first time they're used, like so:

class PropertyFX<T>(value:T):SimpleObjectProperty<T>(value),ReadWriteProperty<Any?,T>{
    private var bean:Any?=null
    private var name=""
    override fun getBean()=bean
    override fun getName()=name
    override fun getValue(thisRef:Any?,property:KProperty<*>):T{
        bean=thisRef
        name=property.name
        return get()
    }
    override fun setValue(thisRef:Any?,property:KProperty<*>,value:T){
        bean=thisRef
        name=property.name
        set(value)
    }

But this seems like an awful hack, and it doesn't return the correct values for getBean() and getName() until the property is accessed once. Is there a way to get these values earlier without passing them into the constructor, like is required by SimpleObjectProperty?

In Kotlin 1.1 (since 1.1-M04), you can use the provideDelegate operator convention to define a function which will be called once when the instance of the delegate is created. In your example, you can declare provideDelegate in PropertyFX and return a new delegate with the information about the container and the property. More info: https://blog.jetbrains.com/kotlin/2016/12/kotlin-1-1-m04-is-here/#provide-delegate