Kotlin: how to pass array to Java annotation

kotlin kotlin-interop
charlie_pl picture charlie_pl · May 19, 2017 · Viewed 8.8k times · Source

I want to use @OneOf annotation from package io.dropwizard.validation;

Java usage: 

@OneOf(value = {"m", "f"})

Kotlin usage: ???

I've tried this: 

 @OneOf(value = arrayOf("m", "f"))

and this:

 @OneOf(value = ["m", "f"])

(EDIT: this example works since Kotlin 1.2, it supports array literal in annotation, thanks @BakaWaii)

All i get is :

Type inference failed. Expected type mismatch:

required: String

found: Array<String>

Kotlin version: 1.1.2-2

Answer

yole picture yole · May 19, 2017

The value parameter is automatically converted to a vararg parameter in Kotlin, as described in http://kotlinlang.org/docs/reference/annotations.html#java-annotations.

The correct syntax for this particular case is @OneOf("m", "f")

Related questions

Comparing two lists in kotlin

I came across with kotlin equals function to compare two list of same type. It works fine for pure Kotlin with data classes. I'am using a Java library in Kotlin project in which a callback method returns a list of …

Read More
Convert Kotlin Array to Java varargs

How can I convert my Kotlin Array to a varargs Java String[]? val angularRoutings = arrayOf<String>("/language", "/home") // this doesn't work web.ignoring().antMatchers(angularRoutings) How to pass an ArrayList to a varargs method parameter?

Read More
How to implement this Java interface in Kotlin?

Since Kotlin doesn't have primitives, how could this interface be implemented? public interface A { @NotNull Object get(@NotNull Integer i); @NotNull Object get(int i); } I cannot change the Java code since it's a compiled class file in a binary …

Read More