Compute property only once

Question

Given the following code

class A
class B {
    val property: A
        get() = A()
}

fun main(args: Array<String>) {
    val b = B()
    println(b.property)
    println(b.property)
}

It returns a new A instance every time B.property. Is there an easy way to make it return the same instance every time?

Answer 1

You can use delegated properties lazy simply, for example:

class B {
    val property by lazy(::A)
}

You can also use a lambda expression instead like this:

class B {
    val property by lazy { A() }
}