[step5] 자동차 경주(리팩터링)

src/main/kotlin/racingcar/RacingCar.kt

@@ -1,33 +1,19 @@
 package racingcar
 
 import racingcar.domain.Cars
-import racingcar.domain.Winners
 import racingcar.util.RandomNumberGenerator
+import racingcar.view.InputView
+import racingcar.view.OutputView
 
 fun main() {
-    println("경주할 자동차 이름을 입력하세요(이름은 쉼표(,)를 기준으로 구분).")
-    val usernames: String = readln()
-    println("시도할 횟수는 몇 회인가요?")
-    val round: Int = readln().toInt()
+    val usernames = InputView.carNames()
+    val round = InputView.roundCount()
 
-    val cars = Cars.usernames(usernames)
+    val cars = Cars.from(usernames)
     repeat(round) {
-        cars.race(RandomNumberGenerator())
-        gameResult(cars)
+        cars.race(RandomNumberGenerator)
+        OutputView.gameResult(cars)
     }
 
-    gameWinner(cars)
-}
-
-private fun gameResult(cars: Cars) {
-    cars.cars().forEach {
-        println(it.username() + " : " + it.position().viewPosition())
-    }
-    println()
-}
-
-private fun gameWinner(cars: Cars) {
-    val winners = Winners(cars)
-    val winnersName = winners.getWinnerNames().joinToString(",")
-    println(winnersName + "가 최종 우승했습니다.")
+    OutputView.gameWinner(cars)
 }

src/main/kotlin/racingcar/domain/Car.kt

@@ -1,18 +1,10 @@
 package racingcar.domain
 
-class Car(private var position: Position, private val username: String) {
+class Car(var position: Position, val username: String) {
     fun move(number: Int) {
         this.position = position.move(number)
     }
 
-    fun position(): Position {
-        return this.position
-    }
-
-    fun username(): String {
-        return this.username
-    }
-
     companion object {
         fun init(username: String): Car {
             return Car(Position.init(), username)

src/main/kotlin/racingcar/domain/Cars.kt

@@ -4,7 +4,7 @@ import racingcar.util.NumberGenerator
 
 private const val USERNAME_SPLIT_CONDITION = ","
 
-class Cars(private val cars: List<Car>) {
+class Cars(val cars: List<Car>) {
     fun race(generator: NumberGenerator) {
         for (car in cars) {
             val number = generator.generate()
@@ -13,19 +13,11 @@ class Cars(private val cars: List<Car>) {
     }
 
     fun positions(): List<Position> {
-        val positions: MutableList<Position> = ArrayList()
-        for (car in cars) {
-            positions.add(car.position())
-        }
-        return positions
-    }
-
-    fun cars(): List<Car> {
-        return cars
+        return cars.map { it.position }
     }
 
     companion object {
-        fun usernames(usernames: String): Cars {
+        fun from(usernames: String): Cars {
             return Cars(usernames.split(USERNAME_SPLIT_CONDITION).map { username -> Car.init(username) })
         }
     }

src/main/kotlin/racingcar/domain/Position.kt

@@ -10,7 +10,7 @@ private const val MOVE_POSITION_CONDITION = 4
 private const val POSITION_VIEW = "-"
 
 @JvmInline
-value class Position(private val position: Int) {
+value class Position(val position: Int) {
     fun move(number: Int): Position {
         if (number < MOVE_START_NUMBER || number > MOVE_END_NUMBER) {
             throw IllegalArgumentException("Only numbers between 0 and 9 can be entered. input number:$number")
@@ -27,10 +27,6 @@ value class Position(private val position: Int) {
         return POSITION_VIEW.repeat(max(DEFAULT_NUMBER, position))
     }
 
-    fun position(): Int {
-        return this.position
-    }
-
     companion object {
         fun init(): Position {
             return Position(DEFAULT_NUMBER)

src/main/kotlin/racingcar/domain/Winners.kt

@@ -5,14 +5,14 @@ class Winners(cars: Cars) {
 
     init {
         val highestPosition: Position =
-            cars.positions().maxByOrNull { it.position() } ?: Position(0)
+            cars.positions().maxByOrNull { it.position } ?: Position.init()
         winners =
-            cars.cars()
-                .filter { it.position() == highestPosition }
+            cars.cars
+                .filter { it.position == highestPosition }
                 .map { it }
     }
 
     fun getWinnerNames(): List<String> {
-        return winners.map { it.username() }
+        return winners.map { it.username }
     }
 }

src/main/kotlin/racingcar/util/RandomNumberGenerator.kt

@@ -4,7 +4,7 @@ import kotlin.random.Random
 
 private const val RANDOM_MAX_NUMBER = 10
 
-class RandomNumberGenerator : NumberGenerator {
+object RandomNumberGenerator : NumberGenerator {
     override fun generate(): Int {
         return Random.nextInt(RANDOM_MAX_NUMBER)
     }

src/main/kotlin/racingcar/view/InputView.kt

@@ -0,0 +1,13 @@
+package racingcar.view
+
+object InputView {
+    fun carNames(): String {
+        println("경주할 자동차 이름을 입력하세요(이름은 쉼표(,)를 기준으로 구분).")
+        return readln()
+    }
+
+    fun roundCount(): Int {
+        println("시도할 횟수는 몇 회인가요?")
+        return readln().toIntOrNull() ?: throw IllegalArgumentException("숫자를 입력해 주세요.")
+    }
+}

src/main/kotlin/racingcar/view/OutputView.kt

@@ -0,0 +1,19 @@
+package racingcar.view
+
+import racingcar.domain.Cars
+import racingcar.domain.Winners
+
+object OutputView {
+    fun gameResult(cars: Cars) {
+        cars.cars.forEach {
+            println(it.username + " : " + it.position.viewPosition())
+        }
+        println()
+    }
+
+    fun gameWinner(cars: Cars) {
+        val winners = Winners(cars)
+        val winnersName = winners.getWinnerNames().joinToString(",")
+        println(winnersName + "가 최종 우승했습니다.")
+    }
+}

src/test/kotlin/racingcar/domain/CarTest.kt

@@ -13,7 +13,7 @@ class CarTest {
 
         car.move(number)
 
-        assertThat(car.position()).isEqualTo(Position(1))
+        assertThat(car.position).isEqualTo(Position(1))
     }
 
     @ParameterizedTest
@@ -23,7 +23,7 @@ class CarTest {
 
         car.move(number)
 
-        assertThat(car.position()).isEqualTo(Position(0))
+        assertThat(car.position).isEqualTo(Position(0))
     }
 
     @ParameterizedTest

src/test/kotlin/racingcar/domain/CarsTest.kt

@@ -7,13 +7,13 @@ import racingcar.TestNumberGenerator
 class CarsTest {
     @Test
     fun `자동차들을 생성한다`() {
-        val cars = Cars.usernames("pobi,crong,honux")
+        val cars = Cars.from("pobi,crong,honux")
         assertThat(cars).isNotNull()
     }
 
     @Test
     fun `자동차 경주 시 4이상의 숫자는 전진한다`() {
-        val cars = Cars.usernames("pobi,crong,honux")
+        val cars = Cars.from("pobi,crong,honux")
 
         cars.race(TestNumberGenerator(4))
 
@@ -22,7 +22,7 @@ class CarsTest {
 
     @Test
     fun `자동차 경주 시작 시 4미만의 숫자는 멈춰 있는다`() {
-        val cars = Cars.usernames("pobi,crong,honux")
+        val cars = Cars.from("pobi,crong,honux")
 
         cars.race(TestNumberGenerator(3))