is there a better way to write this code I m not a big fan o kotlinlang #getting-started

get() {
            if (_fulfillmentDetails == null) {
                _fulfillmentDetails = FulfillmentDetails(this)
            }

            return _fulfillmentDetails!!
        }

diesieben07

11/20/2019, 3:16 PM

return _fulfillmentDetails ?: FulfillmentDetails(this).also { _fulfillmentDetails = it }

11/20/2019, 3:16 PM

thx

michaelsims

11/20/2019, 3:18 PM

Also consider:

val fulfillmentDetails by lazy {
    FulfillmentDetails(this)
}

https://kotlinlang.org/docs/reference/delegated-properties.html#lazy

💯 9

☝️ 2

11/20/2019, 3:26 PM

your suggestion would imply to get rid of the backing field completely?

michaelsims

11/20/2019, 3:31 PM

Yes, there would be no explicit backing field, it would be handled by the delegate. It's nearly identical to your code (except it may allocate another object and it is synchronized by default). You could use the "show kotlin bytecode" option in the IDE then decompile to get an idea of how it is actually implemented

There are ways to avoid the synchronization overhead, see the docs link I posted

11/20/2019, 3:33 PM

i guess the main difference is that i can't check of null anymore without initiating the backing field. Right now I could do sth like if (_fulfillmentDetails == null) { do sth that should only happen if it was never accessed before }

michaelsims

11/20/2019, 3:34 PM

~~True, if you need that sort of logic, the delegate may not be the best option for you.~~

11/20/2019, 3:34 PM

okay, but thanks for the suggestion I have several places where this fits perfectly 😉

👍 1

diesieben07

11/20/2019, 3:37 PM

Lazy exposes a function to check if it's initialized: https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-lazy/is-initialized.html

💯 2

11/20/2019, 3:38 PM

you never learn out, thx

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