Mastering High Performance with Kotlin

Singleton delegate object

If you use equals objects as delegates several times, you can convert a delegate class to an object:

object CalculatorBrain: Calculator {    override fun performOperation(operand: String): Int = TODO()}

Then, you can use an instance of this class as a delegate object:

class CalculatorMachine(): Calculator by CalculatorBrain

Now, you don't need to create a new instance of the delegate object all the time and pass it to a constructor. You can also use a similar approach with delegated properties:

object SingletonDelegate : ReadOnlyProperty<Any?, String?> {    override fun getValue(thisRef: Any?, property: KProperty<*>): String? {        return property.name    }}

We can use SingletonDelegate as follows:

class Main {    val property  ...