how do you folks add constraints to your data clas...

# announcements

[xii]

how do you folks add constraints to your data classes? say if parameter a is null then b cant be not null

[Desmond Teo]

Usually by using sealed classes

[Matteo Mirk]

You can surely use require() inside the init block to check constraints for any class type:
https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/require.html

Regarding your specific question, nullability itself is handled by the compiler by means of nullable types, so your constraint could be expressed like:

class C(val a:Any?, val b:Any)

this tells the compiler that a could be null but b can’t. Is this of any help?

[xii]

i think the require part is what im looking for --- I want A to be nullable, and b only to be non null if A is not null

[xii]

thank you 🙂