Can you name the types of delegates used in Kotlin?

In Kotlin, there are several types of delegates that simplify working with properties:

• Standard delegates:

  • lazy — deferred initialization of a property upon first access.
  • observable — allows tracking changes to the property's value.
  • vetoable — similar to observable, but with the ability to reject changes.
  • notNull — a property that must be initialized before first access, otherwise an exception is thrown.

• Collection delegates: for example, delegates for storing values in a Map.

• Custom delegates: you can implement the ReadOnlyProperty or ReadWriteProperty interfaces to create your own delegates.

Example of using lazy:

val lazyValue: String by lazy {
    println("Calculating value")
    "Hello"
}

fun main() {
    println(lazyValue) // Value is calculated here
    println(lazyValue) // Cached value is used
}