Destructuring types

It is often practical to convert a single object of a complex type into a number of variables. This allows you to provide proper naming for the variables and simplifies the code. Kotlin provides an easy, built-in way to achieve this with a feature called destructuring:

data class User(val login: String, val email: String, val birthday: LocalDate)

fun getUser() = User("Agata", "ag@t.pl", LocalDate.of(1990, 1, 18))

val (name, mail, birthday) = getUser()

print("$name was born on $birthday")

As a result, this piece of code would print the following message to the console:

Agata was born on 1990-01-18

// Java code
public class LightBulb {
    private final int id;
    private boolean turnedOn = false;

    public LightBulb(int id) {
        this.id = id;
    }

    public void setTurnedOn(boolean turnedOn) {
        this.turnedOn = turnedOn;
    }

    public boolean getTurnedOn() {
        return turnedOn;
    }
    
    public int getId() {
        return id;
    }
}