Precondition functions in Kotlin - good practices

Question

Being a newbie Kotlin coder, I wonder, if there are some good practices or even language constructs for declaring pre-conditions in functions.

In Java I have been using Guava's Preconditions checking utilities:

https://github.com/google/guava/wiki/PreconditionsExplained

After some further investigation I came across the require function:

https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/require.html

Is this what is generally used for checking preconditions on functions?

Answer 1

Of course. You can find all of the preconditions in Preconditions.kt. In addition to the require function, there are requireNotNull, check & checkNotNull functions.

Since the documentation describes it poorly in Kotlin, but you can see the Objects#requireNonNull documentation in jdk as further.

Checks that the specified object reference is not null. This method is designed primarily for doing parameter validation in methods and constructors.

Answer 2

I use assert() and require() from the stdlib.

https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/assert.html https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/require.html