Hands-On Design Patterns with Kotlin

Varargs and secondary constructors

Up until now, we were always using the primary constructor of the class. That's the one declared after the class name. But in Java, we can define more than one constructor for a class. Why does Kotlin limit us to only one?

Actually, it doesn't. We can define secondary constructors for a class using the constructor keyword:

class Squad(val infantryUnits: MutableList<InfantryUnit> = mutableListOf()) {    constructor(first: InfantryUnit) : this(mutableListOf()) {        this.infantryUnits.add(first)    }    constructor(first: InfantryUnit,                 second: InfantryUnit) : this(first) {        this.infantryUnits.add(second)    }    constructor(first: InfantryUnit,                 second: InfantryUnit,                 third: InfantryUnit) :         this(first, second) {        this.infantryUnits ...