Functional Kotlin

Annotations

Annotations are a way to attach meta info to your code (such as documentation, configuration, and others).

Let's look at the following example code:

annotation class Tasty

An annotation itself can be annotated to modify its behavior:

@Target(AnnotationTarget.CLASS)@Retention(AnnotationRetention.RUNTIME)annotation class Tasty

In this case, the Tasty annotation can be set on classes, interfaces, and objects, and it can be queried at runtime.

For a complete list of options, check the Kotlin documentation.

Annotations can have parameters with one limitation, they can't be nullable:

@Target(AnnotationTarget.CLASS)@Retention(AnnotationRetention.RUNTIME)annotation class Tasty(val tasty:Boolean = true)@Tasty(false)object ElectricOven ...