requireNotNull
Throws an IllegalArgumentException if the value is null. Otherwise returns the not null value.
Throws an IllegalArgumentException with the result of calling lazyMessage if the value is null. Otherwise returns the not null value.
import kotlin.test.*
fun main(args: Array<String>) {
//sampleStart
fun getIndices(count: Int): List<Int> {
require(count >= 0) { "Count must be non-negative, was $count" }
// ...
return List(count) { it + 1 }
}
// getIndices(-1) // will fail with IllegalArgumentException
println(getIndices(3)) // [1, 2, 3]
//sampleEnd
}