Cache property read from database

Question

Currently I'm starting to learn Kotlin. I have a property like this:

var startTime: Int
    get() = {
        // read value from database
    }
    set(value) {
        // save value to database
    }

Here I always read and write the value every time I use the getter and setter.

Can this property be evaluated lazy? I want to read the value once the first time I use the getter and cache it for following calls. I know that values can be lazy but I found nothing about variables. What is the correct way in Kotlin to cache this property?

Answer 1

Kotlin offers lazy properties (https://kotlinlang.org/docs/reference/delegated-properties.html#lazy) that are computed on first access and cached.

val lazyValue: String by lazy {
  println("computed!")
  "Hello"
}

​

fun main(args: Array<String>) {
  println(lazyValue)
  println(lazyValue)
}

Will produce

computed!
Hello
Hello