I'm wondering if someone can clarify my understanding of backing fields. I have this property define...

# getting-started

[Adam Cooper]

I'm wondering if someone can clarify my understanding of backing fields. I have this property defined in an `object`:

val wordle = Wordle()
        get() {
            if (this.lastWordListRefresh + 1.hours < Clock.System.now()) {
                return Wordle().also {
                    <http://this.log.info|this.log.info>("Refreshing Wordle state")
                    this.lastWordListRefresh = Clock.System.now()
                }
            }
            return field
        }

My understanding was that returning a different value from get would set the backing field. But it seems that, if lastWordListRefresh has "expired", it returns a new object once, and then continues using the old backing object for subsequent calls. Is there a way to make it so that the value returned from get sets the backing field? I essentially want a property that expires, and then lazily refreshes itself.

[David Perez]

The backing field is never automatically updated

[David Perez]

You just need to update the backing field:

val wordle = Wordle()
        get() {
            if (this.lastWordListRefresh + 1.hours < Clock.System.now()) {
                field = Wordle().also {
                    <http://this.log.info|this.log.info>("Refreshing Wordle state")
                    this.lastWordListRefresh = Clock.System.now()
                }
            }
            return field
        }

[Adam Cooper]

It seems that I have to change the property to a var in order to do that. If I don't define the setter, does that mean it can't be updated externally?

[David Perez]

The setter would be public

[David Perez]

But you can make it private:

var wordle = Wordle()
        get() {
            if (this.lastWordListRefresh + 1.hours < Clock.System.now()) {
                field = Wordle().also {
                    <http://this.log.info|this.log.info>("Refreshing Wordle state")
                    this.lastWordListRefresh = Clock.System.now()
                }
            }
            return field
        }
        private set

[Adam Cooper]

Thanks!

[David Perez]

NP and good luck!