prestongarno

import kotlin.reflect.KProperty


class ResponsibleDelegate<out T>(initializer: () -> T?) {

    private val value by lazy(initializer)

    operator fun getValue(thisRef: Any?, property: KProperty<*>): T =
            value ?: throw NullPointerException()
}

prestongarno

fun parsePhoneNumber(text: String): PhoneNumber {
  
  val destructuredRegex = "([0-9]{3})-([0-9]{3})-([0-9]{4})".toRegex()
  
  return destructuredRegex.matchEntire(text)
      ?.destructured
      ?.let { (areaCode, prefix, lineNumber) ->
        PhoneNumber(areaCode.toInt(), prefix.toInt(), lineNumber.toInt())
      } 

prestongarno

import java.io.*;
import java.nio.file.*;
import java.nio.file.spi.FileSystemProvider;
import java.util.*;
import java.util.function.Function;
import java.util.stream.Collectors;
import javax.swing.*;

public class CustomFileChooser {