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fun foo(persons: MutableList<Person>) {
    persons.filter { it.age >= 21 }
           .filter { it.name.startsWith("P") }
           .map { it.name }
           .sorted()
           .forEach(::println)
}

data class Person(val name: String, val age: Int)

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import lombok.Data;

@Data class Person {
    final String name;
}

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val (riddle): String = Person("Peter").component1()
println(riddle) // prints Peter

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data class Person(val name: String)
val (riddle) = Person("Peter")
println(riddle)

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var price: Double by Delegates.vetoable(0.0) { prop, old, new ->
    validate(new)
}

fun validate(price: Double) : Boolean {
    // Validation checks
}

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val prices = listOf(21.8, 232.5, 231.3)
val taxedDiscountedRounded = compose(::taxed, ::discounted, ::rounded)
prices.map(taxedDiscountedRounded)

fun <A, B> compose(f: (A) -> A,
                   g: (A) -> A,
                   h: (A) -> B): (A) -> B = { x -> h(g(f(x))) }

fun taxed(value: Double): Double = value * 1.4
fun discounted(value: Double): Double = value * 0.9

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val prices = listOf(21.8, 232.5, 231.3)
prices.map(::taxed)
      .map(::discounted)
      .map(::rounded)

fun taxed(value: Double): Double = value * 1.4
fun discounted(value: Double): Double = value * 0.9
fun rounded(value: Double): Double = Math.round(value).toDouble()

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// Main.java
public static void main(String[] args) {
    String name = null;

    Nullcheck.ifNull(name, new Function1<Object, Unit>() {
        @Override
        public Unit invoke(Object o) {
            return null;
        }
    });

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// Main.java
public static void main(String[] args) {
    String name = null;

    AnyKt.ifNull(name, new Function1<Object, Unit>() {
        @Override
        public Unit invoke(Object o) {
            return null;
        }
    });

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val button = CustomButton(context)
button.visibility = CustomButton.Visibility.VISIBLE
button.foregroundGravity = CustomButton.ForegroundGravity.LEFT

class CustomButton(context: Context?) : View(context) {

    companion object Visibility {
        val VISIBLE = 1
        val INVISIBLE = 2
    }