Step5 - 리펙토링

README.md

@@ -52,3 +52,11 @@
   * 우승자는 차량 이름으로 표시한다.
 * ResultView에서 우승자 목록을 출력한다.
   * 우승자가 여러명일 경우 쉼표(,)로 구분하여 표시한다.
+
+### Step5
+* 아래 3가지 개발 원칙을 적용해본다
+  * 모든 원시값과 문자열을 포장한다
+  * 3개 이상의 인스턴스 변수를 가진 클래스를 쓰지 않는다.
+  * 한 줄에 점을 하나만 찍는다
+  * 일급 콜렉션을 쓴다
+  * 도메인 객체를 테스트가 가능하도록 수정

src/main/java/race/CarList.java

@@ -0,0 +1,42 @@
+package race;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Random;
+import java.util.stream.Collectors;
+
+public class CarList {
+    private final List<RacingCar> cars;
+
+    public CarList() {
+        this(new ArrayList<>());
+    }
+
+    public CarList(List<RacingCar> cars) {
+        this.cars = cars;
+    }
+
+    public void add(RacingCar car) {
+        cars.add(car);
+    }
+
+    public void moveWithRandom(Random random) {
+        for (RacingCar car : cars) {
+            car.moveWithSeed(random.nextInt());
+        }
+    }
+
+    public List<RacingCar> getList() {
+        return cars;
+    }
+
+    public List<RacingCar> getWinners() {
+        cars.sort(Collections.reverseOrder());
+        RacingCar winner = cars.get(0);
+
+        return cars.stream()
+                .filter(car -> car.compareTo(winner) == 0)
+                .collect(Collectors.toList());
+    }
+}

src/main/java/race/CarName.java

@@ -0,0 +1,15 @@
+package race;
+
+public class CarName {
+    private final String name;
+
+    public CarName(String name) {
+        this.name = name;
+    }
+
+    @Override
+    public String toString() {
+        return name;
+    }
+
+}

src/main/java/race/Position.java

@@ -0,0 +1,42 @@
+package race;
+
+import java.util.Objects;
+
+public class Position implements Comparable<Position> {
+    private int value;
+
+    public Position() {
+        this(0);
+    }
+
+    public Position(int value) {
+        this.value = value;
+    }
+
+    public Position move() {
+        this.value++;
+        return this;
+    }
+
+    public int getValue() {
+        return this.value;
+    }
+
+    @Override
+    public int compareTo(Position o) {
+        return Integer.compare(this.value, o.value);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
+        Position position = (Position) obj;
+        return value == position.value;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(value);
+    }
+}

src/main/java/race/RacingCar.java

@@ -2,47 +2,44 @@
 
 public class RacingCar implements Comparable<RacingCar> {
     private static final int MAX_NAME_LENGTH = 5;
-    private final String name;
-    private int position;
-    private final RandomNumberGenerator randomNumberGenerator;
-    private final PositionPrinter positionPrinter;
+    private static final int MOVE_CRITERIA = 4;
+    private final CarName name;
+    private final Position position;
 
-    private RacingCar(String name, RandomNumberGenerator randomNumberGenerator, PositionPrinter positionPrinter) {
-        this.name = name;
-        this.randomNumberGenerator = randomNumberGenerator;
-        this.positionPrinter = positionPrinter;
+    public RacingCar(String name) {
+        this(name, 0);
     }
 
-    @Override
-    public int compareTo(RacingCar other) {
-        return Integer.compare(this.position, other.position);
+    public RacingCar(String name, int position) {
+        this.name = new CarName(name);
+        this.position = new Position(position);
     }
 
     public static boolean validateName(String carName) {
         return !carName.isEmpty() && carName.length() <= MAX_NAME_LENGTH;
     }
 
     private boolean shouldMove(int num) {
-        return num >= 4;
+        return num >= MOVE_CRITERIA;
     }
 
-    public int move() {
-        int randomValue = randomNumberGenerator.generate();
-        if (shouldMove(randomValue)) {
-            position++;
+    public Position moveWithSeed(int seed) {
+        if (shouldMove(seed)) {
+            return this.position.move();
         }
-        return position;
+        return this.position;
     }
 
-    public void printPosition() {
-        positionPrinter.printPosition(name, position);
+    public CarName getName() {
+        return this.name;
     }
 
-    static RacingCar create(String racingName, RandomNumberGenerator randomNumberGenerator, PositionPrinter positionPrinter) {
-        return new RacingCar(racingName, randomNumberGenerator, positionPrinter);
+    public Position getPosition() {
+        return this.position;
     }
 
-    public String getName() {
-        return name;
+    @Override
+    public int compareTo(RacingCar o) {
+        return this.position.compareTo(o.position);
     }
 }

src/main/java/race/RacingTrack.java

@@ -1,63 +1,43 @@
 package race;
 
-import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
+import java.util.Random;
 
 public class RacingTrack {
-    private final int maxCarCount;
-    private final int maxAttemptCount;
-    private final List<RacingCar> cars;
+    private final TrackCondition trackCondition;
+    private final CarList cars;
 
     public RacingTrack(int maxCarCount, int maxAttemptCount) {
-        this.maxCarCount = maxCarCount;
-        this.maxAttemptCount = maxAttemptCount;
-        this.cars = new ArrayList<>();
+        this.trackCondition = new TrackCondition(maxCarCount, maxAttemptCount);
+        this.cars = new CarList();
     }
 
     public void startRace(String[] carNames, int numOfAttempts) {
         setupCars(carNames);
 
         ResultView.printRaceStartMessage();
         for (int i = 0; i < numOfAttempts; i++) {
-            moveAndShowCars();
-            ResultView.printRaceStatus(cars);
-        }
-    }
-
-    // getWinners() 메서드 테스틀 위하여 추가한 생성자
-    public void startRace(List<RacingCar> cars, int numOfAttempts) {
-        this.cars.addAll(cars);
-
-        ResultView.printRaceStartMessage();
-        for (int i = 0; i < numOfAttempts; i++) {
-            moveAndShowCars();
+            cars.moveWithRandom(new Random());
             ResultView.printRaceStatus(cars);
         }
     }
 
     private void setupCars(String[] carNames) {
         for (String name : carNames) {
-            cars.add(RacingCarFactory.create(name, ResultView.createPositionPrinter()));
-        }
-    }
-
-    private void moveAndShowCars() {
-        for (RacingCar car : cars) {
-            car.move();
+            cars.add(new RacingCar(name));
         }
     }
 
     public boolean validateCarCount(int num) {
-        return num >= 1 && num <= this.maxCarCount;
+        return this.trackCondition.validateCarCount(num);
     }
 
     public boolean validateAttemptCount(int num) {
-        return num >= 1 && num <= this.maxAttemptCount;
+        return this.trackCondition.validateAttemptCount(num);
     }
 
     public boolean validateCarNames(String[] names) {
-        if (names.length < 1 || names.length > this.maxCarCount) {
+        if (!this.trackCondition.validateCarCount(names.length)) {
             return false;
         }
         for (String name : names) {
@@ -67,13 +47,6 @@ public boolean validateCarNames(String[] names) {
     }
 
     public List<RacingCar> getWinners() {
-        cars.sort(Collections.reverseOrder());
-        List<RacingCar> winners = new ArrayList<>();
-        winners.add(cars.get(0));
-
-        for (int i = 1; i < cars.size(); i++) {
-            if (cars.get(i).compareTo(cars.get(0)) == 0) winners.add(cars.get(i));
-        }
-        return winners;
+        return this.cars.getWinners();
     }
 }

src/main/java/race/ResultView.java

@@ -3,30 +3,21 @@
 import java.util.List;
 
 public class ResultView {
-    public static PositionPrinter createPositionPrinter() {
-        return new PositionPrinter() {
-            @Override
-            public void printPosition(String carName, int position) {
-                System.out.println(String.format("%-5s", carName) + " : " + "-".repeat(position));
-            }
-        };
-    }
-
     public static void printRaceStartMessage() {
         System.out.println("\n### Racing Start!!! ###\n");
     }
 
-    public static void printRaceStatus(List<RacingCar> cars) {
-        for (RacingCar car : cars) {
-            car.printPosition();
+    public static void printRaceStatus(CarList cars) {
+        for (RacingCar car : cars.getList()) {
+            System.out.println(String.format("%-5s", car.getName().toString()) + " : " + "-".repeat(car.getPosition().getValue()));
         }
         System.out.println();
     }
 
     public static void printRaceWinners(List<RacingCar> cars) {
         String[] winners = new String[cars.size()];
         for (RacingCar car : cars) {
-            winners[cars.indexOf(car)] = car.getName();
+            winners[cars.indexOf(car)] = car.getName().toString();
         }
         System.out.println(String.join(", ", winners) + "가 최종 우승했습니다.");
     }

src/main/java/race/TrackCondition.java

@@ -0,0 +1,19 @@
+package race;
+
+public class TrackCondition {
+    private final int maxCarCount;
+    private final int maxAttemptCount;
+
+    public TrackCondition(int maxCarCount, int maxAttemptCount) {
+        this.maxCarCount = maxCarCount;
+        this.maxAttemptCount = maxAttemptCount;
+    }
+
+    public boolean validateCarCount(int num) {
+        return num >= 1 && num <= this.maxCarCount;
+    }
+
+    public boolean validateAttemptCount(int num) {
+        return num >= 1 && num <= this.maxAttemptCount;
+    }
+}