From 68d651dccb87624059bbf2b88fa9bfe2c1c31ae2 Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Wed, 28 Jan 2026 16:33:37 +0900
Subject: [PATCH 01/29] docs(readme): update project description

---
 README.md                      | 68 +++++++++++++++++++++++++++++++++-
 src/main/java/Application.java |  0
 2 files changed, 67 insertions(+), 1 deletion(-)
 create mode 100644 src/main/java/Application.java

diff --git a/README.md b/README.md
index 8d7e8aee..22708bf0 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,67 @@
-# java-baseball-precourse
\ No newline at end of file
+# java-baseball-precourse
+
+## ⚾ 숫자 야구 게임 구현 기능 목록
+
+### 1. 게임 실행
+- 프로그램 시작 시 숫자 야구 게임을 실행한다.
+- 사용자에게 게임 시작 안내 문구를 출력한다.
+
+---
+
+### 2. 숫자 야구 게임 정답 생성
+- 컴퓨터는 1~9 사이의 서로 다른 숫자 3개를 랜덤으로 생성한다.
+- 생성된 숫자는 게임이 끝날 때까지 정답으로 유지한다.
+
+---
+
+### 3. 사용자 입력 처리
+- 사용자가 3자리 숫자를 입력한다.
+- 입력은 한 번에 문자열 형태로 받는다.
+
+---
+
+### 4. 입력 검증
+사용자의 입력이 올바른 형식인지 검증한다.
+
+#### 4-2. 입력 길이가 3인지 확인
+- 입력값이 정확히 3자리인지 검사한다.
+
+#### 4-2. 숫자만 입력되었는지 확인
+- 입력값이 1-9 사이의 숫자로만 구성되어 있는지 검사한다.
+
+#### 4-3. 중복 숫가 존재하는 지 확인
+- 입력값이 1-9 사이의 숫자로만 구성되어 있는지 검사한다.
+
+#### 4-4. 예외 발생 시 출력
+- 잘못된 입력이 들어오면 [ERROR]로 시작하는 메시지를 출력한다.
+
+---
+
+### 5. 판정 로직
+입력값과 정답을 비교하여 결과를 판정한다.
+
+#### 5-1. Strike 판정
+- 숫자와 위치가 모두 일치하면 `strike`로 판단한다.
+
+#### 5-2. Ball 판정
+- 숫자는 포함되지만 위치가 다르면 `ball`로 판단한다.
+
+#### 5-3. Nothing 판정
+- 일치하는 숫자가 하나도 없다면 `낫싱`을 출력한다.
+
+---
+
+### 6. 결과 출력
+- 판정 결과에 따라 `볼`, `스트라이크`, `낫싱`을 출력한다.
+- 3 strike가 되면 게임 종료 문구를 출력한다.
+
+---
+
+### 7. 재시작 및 종료
+게임이 종료된 후 사용자의 선택을 입력받는다.
+
+#### 7-1. 게임 재시작
+- 사용자가 `1`을 입력하면 새로운 게임을 시작한다.
+
+#### 7-2. 게임 종료
+- 사용자가 `2`를 입력하면 프로그램을 종료한다.
diff --git a/src/main/java/Application.java b/src/main/java/Application.java
new file mode 100644
index 00000000..e69de29b

From c5d5e9ceb94542373ece11f8d86db198ec975d54 Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Wed, 28 Jan 2026 17:24:14 +0900
Subject: [PATCH 02/29] chore: set up initial project structure

---
 README.md                                    | 6 ++++--
 build.gradle                                 | 5 +++++
 src/main/java/Application.java               | 7 +++++++
 src/main/java/controller/GameController.java | 5 +++++
 src/main/java/view/Message.java              | 4 ++++
 src/main/java/view/OutputView.java           | 4 ++++
 6 files changed, 29 insertions(+), 2 deletions(-)
 create mode 100644 src/main/java/controller/GameController.java
 create mode 100644 src/main/java/view/Message.java
 create mode 100644 src/main/java/view/OutputView.java

diff --git a/README.md b/README.md
index 22708bf0..483c5eca 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-# java-baseball-precourse
+~~# java-baseball-precourse
 
 ## ⚾ 숫자 야구 게임 구현 기능 목록
 
@@ -64,4 +64,6 @@
 - 사용자가 `1`을 입력하면 새로운 게임을 시작한다.
 
 #### 7-2. 게임 종료
-- 사용자가 `2`를 입력하면 프로그램을 종료한다.
+- 사용자가 `2`를 입력하면 프로그램을 종료한다.~~
+
+
diff --git a/build.gradle b/build.gradle
index 20a92c9e..a620394e 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,5 +1,6 @@
 plugins {
     id 'java'
+    id 'application'
 }
 
 group = 'camp.nextstep.edu'
@@ -23,3 +24,7 @@ dependencies {
 test {
     useJUnitPlatform()
 }
+
+application {
+    mainClass = 'Application'
+}
diff --git a/src/main/java/Application.java b/src/main/java/Application.java
index e69de29b..cee41f4f 100644
--- a/src/main/java/Application.java
+++ b/src/main/java/Application.java
@@ -0,0 +1,7 @@
+import controller.GameController;
+
+public class Application {
+    public static void main(String[] args) {
+        new GameController().run();
+    }
+}
diff --git a/src/main/java/controller/GameController.java b/src/main/java/controller/GameController.java
new file mode 100644
index 00000000..da4e765d
--- /dev/null
+++ b/src/main/java/controller/GameController.java
@@ -0,0 +1,5 @@
+package controller;
+
+public class GameController {
+
+}
diff --git a/src/main/java/view/Message.java b/src/main/java/view/Message.java
new file mode 100644
index 00000000..7900e337
--- /dev/null
+++ b/src/main/java/view/Message.java
@@ -0,0 +1,4 @@
+package view;
+
+public class Message {
+}
diff --git a/src/main/java/view/OutputView.java b/src/main/java/view/OutputView.java
new file mode 100644
index 00000000..d8f9743c
--- /dev/null
+++ b/src/main/java/view/OutputView.java
@@ -0,0 +1,4 @@
+package view;
+
+public class OutputView {
+}

From f0f1a4236935f33dfbf036ded7b0eb2e28fecbc6 Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Wed, 28 Jan 2026 17:30:43 +0900
Subject: [PATCH 03/29] feat(game): add start message output

---
 src/main/java/controller/GameController.java | 6 ++++++
 src/main/java/view/Message.java              | 1 +
 src/main/java/view/OutputView.java           | 3 +++
 3 files changed, 10 insertions(+)

diff --git a/src/main/java/controller/GameController.java b/src/main/java/controller/GameController.java
index da4e765d..0e141b61 100644
--- a/src/main/java/controller/GameController.java
+++ b/src/main/java/controller/GameController.java
@@ -1,5 +1,11 @@
 package controller;
 
+import view.OutputView;
+
 public class GameController {
+    private final OutputView outputView = new OutputView();
 
+    public void run() {
+        outputView.printStartMessage();
+    }
 }
diff --git a/src/main/java/view/Message.java b/src/main/java/view/Message.java
index 7900e337..5e7a48ad 100644
--- a/src/main/java/view/Message.java
+++ b/src/main/java/view/Message.java
@@ -1,4 +1,5 @@
 package view;
 
 public class Message {
+    public static final String START_MESSAGE = "숫자 야구 게임 시작";
 }
diff --git a/src/main/java/view/OutputView.java b/src/main/java/view/OutputView.java
index d8f9743c..af0f3461 100644
--- a/src/main/java/view/OutputView.java
+++ b/src/main/java/view/OutputView.java
@@ -1,4 +1,7 @@
 package view;
 
 public class OutputView {
+    public void printStartMessage() {
+        System.out.println(Message.START_MESSAGE);
+    }
 }

From 996b98e9b120a4bccde871ea9430e47c0d896973 Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Wed, 28 Jan 2026 18:06:49 +0900
Subject: [PATCH 04/29] feat(game) add random number generation

---
 .../java/service/RandomNumberGenerator.java    | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)
 create mode 100644 src/main/java/service/RandomNumberGenerator.java

diff --git a/src/main/java/service/RandomNumberGenerator.java b/src/main/java/service/RandomNumberGenerator.java
new file mode 100644
index 00000000..30352ee2
--- /dev/null
+++ b/src/main/java/service/RandomNumberGenerator.java
@@ -0,0 +1,18 @@
+package service;
+
+import java.util.concurrent.ThreadLocalRandom;
+
+public class RandomNumberGenerator {
+    static String makeAnswer() {
+        int[] d = {1, 2, 3, 4, 5, 6, 7, 8, 9};
+
+        for (int i = d.length - 1; i > 0; i--) {
+            int j = ThreadLocalRandom.current().nextInt(i + 1);
+            int tmp = d[i];
+            d[i] = d[j];
+            d[j] = tmp;
+        }
+
+        return "" + d[0] + d[1] + d[2];
+    }
+}

From 4c975608d619709bfb919235d05473f6c0fc423b Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Wed, 28 Jan 2026 18:34:34 +0900
Subject: [PATCH 05/29] feat(game) add GameController get answer

---
 src/main/java/controller/GameController.java     |  9 +++++++++
 src/main/java/domain/ComputerNumber.java         | 13 +++++++++++++
 src/main/java/service/ComputerNumberService.java | 13 +++++++++++++
 3 files changed, 35 insertions(+)
 create mode 100644 src/main/java/domain/ComputerNumber.java
 create mode 100644 src/main/java/service/ComputerNumberService.java

diff --git a/src/main/java/controller/GameController.java b/src/main/java/controller/GameController.java
index 0e141b61..c60845f1 100644
--- a/src/main/java/controller/GameController.java
+++ b/src/main/java/controller/GameController.java
@@ -1,11 +1,20 @@
 package controller;
 
+import domain.ComputerNumber;
+import service.ComputerNumberService;
 import view.OutputView;
 
 public class GameController {
     private final OutputView outputView = new OutputView();
 
+    private final ComputerNumberService computerNumberService =
+            new ComputerNumberService();
+
     public void run() {
         outputView.printStartMessage();
+
+        ComputerNumber answer = computerNumberService.create();
+
+//        System.out.println(answer.getNumbers());
     }
 }
diff --git a/src/main/java/domain/ComputerNumber.java b/src/main/java/domain/ComputerNumber.java
new file mode 100644
index 00000000..2adab77c
--- /dev/null
+++ b/src/main/java/domain/ComputerNumber.java
@@ -0,0 +1,13 @@
+package domain;
+
+public class ComputerNumber {
+    private final String numbers;
+
+    public ComputerNumber(String numbers) {
+        this.numbers = numbers;
+    }
+
+    public String getNumbers() {
+        return numbers;
+    }
+}
diff --git a/src/main/java/service/ComputerNumberService.java b/src/main/java/service/ComputerNumberService.java
new file mode 100644
index 00000000..c4347c15
--- /dev/null
+++ b/src/main/java/service/ComputerNumberService.java
@@ -0,0 +1,13 @@
+package service;
+
+import domain.ComputerNumber;
+
+public class ComputerNumberService {
+    public ComputerNumberService() {
+    }
+
+    public ComputerNumber create() {
+        String numbers = RandomNumberGenerator.makeAnswer();
+        return new ComputerNumber(numbers);
+    }
+}

From d289ad291292d87d3c66afa0407caf170aa1d690 Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Sun, 1 Feb 2026 20:50:20 +0900
Subject: [PATCH 06/29] feat(game): add print enter usernumber

---
 src/main/java/controller/GameController.java |  7 ++++++-
 src/main/java/domain/ComputerNumber.java     | 11 +----------
 src/main/java/view/InputView.java            | 14 ++++++++++++++
 src/main/java/view/Message.java              |  5 -----
 src/main/java/view/OutputView.java           |  2 +-
 5 files changed, 22 insertions(+), 17 deletions(-)
 create mode 100644 src/main/java/view/InputView.java
 delete mode 100644 src/main/java/view/Message.java

diff --git a/src/main/java/controller/GameController.java b/src/main/java/controller/GameController.java
index c60845f1..7c08a662 100644
--- a/src/main/java/controller/GameController.java
+++ b/src/main/java/controller/GameController.java
@@ -2,10 +2,12 @@
 
 import domain.ComputerNumber;
 import service.ComputerNumberService;
+import view.InputView;
 import view.OutputView;
 
 public class GameController {
     private final OutputView outputView = new OutputView();
+    private final InputView inputView = new InputView();
 
     private final ComputerNumberService computerNumberService =
             new ComputerNumberService();
@@ -15,6 +17,9 @@ public void run() {
 
         ComputerNumber answer = computerNumberService.create();
 
-//        System.out.println(answer.getNumbers());
+        String guess = inputView.readGuess();
+
+//        System.out.println(answer.numbers());
+//        System.out.println(guess);
     }
 }
diff --git a/src/main/java/domain/ComputerNumber.java b/src/main/java/domain/ComputerNumber.java
index 2adab77c..d1575983 100644
--- a/src/main/java/domain/ComputerNumber.java
+++ b/src/main/java/domain/ComputerNumber.java
@@ -1,13 +1,4 @@
 package domain;
 
-public class ComputerNumber {
-    private final String numbers;
-
-    public ComputerNumber(String numbers) {
-        this.numbers = numbers;
-    }
-
-    public String getNumbers() {
-        return numbers;
-    }
+public record ComputerNumber(String numbers) {
 }
diff --git a/src/main/java/view/InputView.java b/src/main/java/view/InputView.java
new file mode 100644
index 00000000..bc185bd1
--- /dev/null
+++ b/src/main/java/view/InputView.java
@@ -0,0 +1,14 @@
+package view;
+
+import java.util.Scanner;
+
+public class InputView {
+    private static final Scanner scanner = new Scanner(System.in);
+
+    public String readGuess() {
+        System.out.print("숫자를 입력해 주세요: ");
+        return scanner.nextLine();
+    }
+
+
+}
diff --git a/src/main/java/view/Message.java b/src/main/java/view/Message.java
deleted file mode 100644
index 5e7a48ad..00000000
--- a/src/main/java/view/Message.java
+++ /dev/null
@@ -1,5 +0,0 @@
-package view;
-
-public class Message {
-    public static final String START_MESSAGE = "숫자 야구 게임 시작";
-}
diff --git a/src/main/java/view/OutputView.java b/src/main/java/view/OutputView.java
index af0f3461..f62ee0d4 100644
--- a/src/main/java/view/OutputView.java
+++ b/src/main/java/view/OutputView.java
@@ -2,6 +2,6 @@
 
 public class OutputView {
     public void printStartMessage() {
-        System.out.println(Message.START_MESSAGE);
+        System.out.println("숫자 야구 게임 시작");
     }
 }

From 7eb46e66ece3b9f016cdea467aaa09f24284ad2c Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Sun, 1 Feb 2026 21:25:14 +0900
Subject: [PATCH 07/29] refactor: reorganize domain (add Numbers class)

---
 src/main/java/controller/GameController.java  |  8 ++---
 src/main/java/domain/ComputerNumber.java      |  4 ---
 src/main/java/domain/Numbers.java             | 30 +++++++++++++++++++
 .../java/service/ComputerNumberService.java   | 13 --------
 src/main/java/service/GameService.java        |  5 ++++
 .../java/service/RandomNumberGenerator.java   | 20 ++++++++-----
 6 files changed, 50 insertions(+), 30 deletions(-)
 delete mode 100644 src/main/java/domain/ComputerNumber.java
 create mode 100644 src/main/java/domain/Numbers.java
 delete mode 100644 src/main/java/service/ComputerNumberService.java
 create mode 100644 src/main/java/service/GameService.java

diff --git a/src/main/java/controller/GameController.java b/src/main/java/controller/GameController.java
index 7c08a662..b6b996d0 100644
--- a/src/main/java/controller/GameController.java
+++ b/src/main/java/controller/GameController.java
@@ -1,7 +1,6 @@
 package controller;
 
-import domain.ComputerNumber;
-import service.ComputerNumberService;
+import domain.Numbers;
 import view.InputView;
 import view.OutputView;
 
@@ -9,14 +8,11 @@ public class GameController {
     private final OutputView outputView = new OutputView();
     private final InputView inputView = new InputView();
 
-    private final ComputerNumberService computerNumberService =
-            new ComputerNumberService();
+
 
     public void run() {
         outputView.printStartMessage();
 
-        ComputerNumber answer = computerNumberService.create();
-
         String guess = inputView.readGuess();
 
 //        System.out.println(answer.numbers());
diff --git a/src/main/java/domain/ComputerNumber.java b/src/main/java/domain/ComputerNumber.java
deleted file mode 100644
index d1575983..00000000
--- a/src/main/java/domain/ComputerNumber.java
+++ /dev/null
@@ -1,4 +0,0 @@
-package domain;
-
-public record ComputerNumber(String numbers) {
-}
diff --git a/src/main/java/domain/Numbers.java b/src/main/java/domain/Numbers.java
new file mode 100644
index 00000000..3ebccaca
--- /dev/null
+++ b/src/main/java/domain/Numbers.java
@@ -0,0 +1,30 @@
+package domain;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Numbers {
+    private final List<Integer> numbers;
+
+    private Numbers(List<Integer> numbers) {
+        this.numbers = numbers;
+    }
+
+    public static Numbers from(String input) {
+        return new Numbers(parse(input));
+    }
+
+    private static List<Integer> parse(String input) {
+        List<Integer> nums = new ArrayList<>(3);
+        for (int i = 0; i < 3; i++) nums.add(input.charAt(i) - '0');
+        return nums;
+    }
+
+    public int get(int index) {
+        return numbers.get(index);
+    }
+
+    public boolean contains(int number) {
+        return numbers.contains(number);
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/service/ComputerNumberService.java b/src/main/java/service/ComputerNumberService.java
deleted file mode 100644
index c4347c15..00000000
--- a/src/main/java/service/ComputerNumberService.java
+++ /dev/null
@@ -1,13 +0,0 @@
-package service;
-
-import domain.ComputerNumber;
-
-public class ComputerNumberService {
-    public ComputerNumberService() {
-    }
-
-    public ComputerNumber create() {
-        String numbers = RandomNumberGenerator.makeAnswer();
-        return new ComputerNumber(numbers);
-    }
-}
diff --git a/src/main/java/service/GameService.java b/src/main/java/service/GameService.java
new file mode 100644
index 00000000..4d549a6c
--- /dev/null
+++ b/src/main/java/service/GameService.java
@@ -0,0 +1,5 @@
+package service;
+
+public class GameService {
+
+}
diff --git a/src/main/java/service/RandomNumberGenerator.java b/src/main/java/service/RandomNumberGenerator.java
index 30352ee2..94580d27 100644
--- a/src/main/java/service/RandomNumberGenerator.java
+++ b/src/main/java/service/RandomNumberGenerator.java
@@ -3,16 +3,22 @@
 import java.util.concurrent.ThreadLocalRandom;
 
 public class RandomNumberGenerator {
-    static String makeAnswer() {
-        int[] d = {1, 2, 3, 4, 5, 6, 7, 8, 9};
+    public String numberGenerate() {
+        int[] numbers = {1, 2, 3, 4, 5, 6, 7, 8, 9};
+        shuffle(numbers);
+        return "" + numbers[0] + numbers[1] + numbers[2];
+    }
 
-        for (int i = d.length - 1; i > 0; i--) {
+    private void shuffle(int[] arr) {
+        for (int i = arr.length - 1; i > 0; i--) {
             int j = ThreadLocalRandom.current().nextInt(i + 1);
-            int tmp = d[i];
-            d[i] = d[j];
-            d[j] = tmp;
+            swap(arr, i, j);
         }
+    }
 
-        return "" + d[0] + d[1] + d[2];
+    private void swap(int[] arr, int i, int j) {
+        int tmp = arr[i];
+        arr[i] = arr[j];
+        arr[j] = tmp;
     }
 }

From 67d20be7d85a681dcbed2afe446c3075e1e6d8c0 Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Sun, 1 Feb 2026 21:51:59 +0900
Subject: [PATCH 08/29] refactor: add GameService, change GameController

---
 src/main/java/Application.java                   | 12 +++++++++++-
 src/main/java/controller/GameController.java     | 16 +++++++++-------
 src/main/java/service/GameService.java           | 11 +++++++++++
 src/main/java/service/RandomNumberGenerator.java |  6 ++++--
 4 files changed, 35 insertions(+), 10 deletions(-)

diff --git a/src/main/java/Application.java b/src/main/java/Application.java
index cee41f4f..69560bc3 100644
--- a/src/main/java/Application.java
+++ b/src/main/java/Application.java
@@ -1,7 +1,17 @@
 import controller.GameController;
+import service.GameService;
+import view.InputView;
+import view.OutputView;
+import service.RandomNumberGenerator;
 
 public class Application {
     public static void main(String[] args) {
-        new GameController().run();
+        InputView inputView = new InputView();
+        OutputView outputView = new OutputView();
+        GameService gameService = new GameService(
+                new RandomNumberGenerator()
+        );
+
+        new GameController(inputView, outputView, gameService).run();
     }
 }
diff --git a/src/main/java/controller/GameController.java b/src/main/java/controller/GameController.java
index b6b996d0..aa513f34 100644
--- a/src/main/java/controller/GameController.java
+++ b/src/main/java/controller/GameController.java
@@ -1,21 +1,23 @@
 package controller;
 
 import domain.Numbers;
+import service.GameService;
 import view.InputView;
 import view.OutputView;
 
 public class GameController {
-    private final OutputView outputView = new OutputView();
-    private final InputView inputView = new InputView();
-
+    private final InputView inputView;
+    private final OutputView outputView;
+    private final GameService gameService;
 
+    public GameController(InputView inputView, OutputView outputView, GameService gameService) {
+        this.inputView = inputView;
+        this.outputView = outputView;
+        this.gameService = gameService;
+    }
 
     public void run() {
         outputView.printStartMessage();
-
         String guess = inputView.readGuess();
-
-//        System.out.println(answer.numbers());
-//        System.out.println(guess);
     }
 }
diff --git a/src/main/java/service/GameService.java b/src/main/java/service/GameService.java
index 4d549a6c..b7dfec2d 100644
--- a/src/main/java/service/GameService.java
+++ b/src/main/java/service/GameService.java
@@ -1,5 +1,16 @@
 package service;
 
+import domain.Numbers;
+
 public class GameService {
+    private final RandomNumberGenerator randomNumberGenerator;
+    private Numbers answer;
+
+    public GameService(RandomNumberGenerator randomNumberGenerator) {
+        this.randomNumberGenerator = randomNumberGenerator;
+    }
 
+    public void startNewGame() {
+        answer = randomNumberGenerator.numberGenerate();
+    }
 }
diff --git a/src/main/java/service/RandomNumberGenerator.java b/src/main/java/service/RandomNumberGenerator.java
index 94580d27..0838d9f2 100644
--- a/src/main/java/service/RandomNumberGenerator.java
+++ b/src/main/java/service/RandomNumberGenerator.java
@@ -1,12 +1,14 @@
 package service;
 
+import domain.Numbers;
+
 import java.util.concurrent.ThreadLocalRandom;
 
 public class RandomNumberGenerator {
-    public String numberGenerate() {
+    public Numbers numberGenerate() {
         int[] numbers = {1, 2, 3, 4, 5, 6, 7, 8, 9};
         shuffle(numbers);
-        return "" + numbers[0] + numbers[1] + numbers[2];
+        return Numbers.from("" + numbers[0] + numbers[1] + numbers[2]);
     }
 
     private void shuffle(int[] arr) {

From 327bac102ad20d711c5d80210c4eac0760f373e4 Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Sun, 1 Feb 2026 22:20:27 +0900
Subject: [PATCH 09/29] feat(game) add inputValidator - check input

---
 src/main/java/util/InputValidator.java | 46 ++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 src/main/java/util/InputValidator.java

diff --git a/src/main/java/util/InputValidator.java b/src/main/java/util/InputValidator.java
new file mode 100644
index 00000000..689444fb
--- /dev/null
+++ b/src/main/java/util/InputValidator.java
@@ -0,0 +1,46 @@
+package util;
+
+import java.util.HashSet;
+import java.util.Set;
+
+public class InputValidator {
+    private static final String ERROR_PREFIX = "[ERROR] ";
+    private static final int INPUT_LENGTH = 3;
+    private static final String RESTART_CODE = "1";
+    private static final String EXIT_CODE = "2";
+
+    public static String guessError(String input) {
+        if (input.length() != INPUT_LENGTH) {
+            return errorMessage(INPUT_LENGTH + "자여야 합니다.");
+        }
+        return validateCharacters(input);
+    }
+
+    private static String validateCharacters(String input) {
+        Set<Character> uniqueChars = new HashSet<>();
+
+        for (char c : input.toCharArray()) {
+            if (!Character.isDigit(c)) {
+                return errorMessage("숫자만 입력해야 합니다.");
+            }
+            if (c == '0') {
+                return errorMessage("0은 사용할 수 없습니다.");
+            }
+            if (!uniqueChars.add(c)) {
+                return errorMessage("중복된 숫자는 사용할 수 없습니다.");
+            }
+        }
+        return null;
+    }
+
+    public static String restartError(String input) {
+        if (RESTART_CODE.equals(input) || EXIT_CODE.equals(input)) {
+            return null;
+        }
+        return errorMessage(String.format("재시작은 %s, 종료는 %s만 입력 가능합니다.", RESTART_CODE, EXIT_CODE));
+    }
+
+    private static String errorMessage(String message) {
+        return ERROR_PREFIX + message;
+    }
+}

From 2ffff42b0a7ab84983ed18ce6c924cc1e7a4e727 Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Sun, 1 Feb 2026 22:30:14 +0900
Subject: [PATCH 10/29] feat(domain): add new domain model(JudgeCount)

---
 src/main/java/domain/JudgeCount.java    | 33 +++++++++++++++++++++++++
 src/main/java/service/JudgeService.java |  5 ++++
 2 files changed, 38 insertions(+)
 create mode 100644 src/main/java/domain/JudgeCount.java
 create mode 100644 src/main/java/service/JudgeService.java

diff --git a/src/main/java/domain/JudgeCount.java b/src/main/java/domain/JudgeCount.java
new file mode 100644
index 00000000..a619876f
--- /dev/null
+++ b/src/main/java/domain/JudgeCount.java
@@ -0,0 +1,33 @@
+package domain;
+
+public class JudgeCount {
+    private final int ball;
+    private final int strike;
+
+    public JudgeCount(int ball, int strike) {
+        this.ball = ball;
+        this.strike = strike;
+    }
+
+    public boolean isThreeStrikes() {
+        return strike == 3;
+    }
+
+    public String toMessage() {
+        if (ball == 0 && strike == 0) return "낫싱";
+        StringBuilder sb = new StringBuilder();
+        appendBall(sb);
+        appendStrike(sb);
+        return sb.toString().trim();
+    }
+
+    private void appendBall(StringBuilder sb) {
+        if (ball == 0) return;
+        sb.append(ball).append("볼 ");
+    }
+
+    private void appendStrike(StringBuilder sb) {
+        if (strike == 0) return;
+        sb.append(strike).append("스트라이크");
+    }
+}
diff --git a/src/main/java/service/JudgeService.java b/src/main/java/service/JudgeService.java
new file mode 100644
index 00000000..df9dbeb1
--- /dev/null
+++ b/src/main/java/service/JudgeService.java
@@ -0,0 +1,5 @@
+package service;
+
+public class JudgeService {
+    public
+}

From 3f98fc31ef173a109ab1ff080430bbec5a2a1cb7 Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Sun, 1 Feb 2026 22:47:19 +0900
Subject: [PATCH 11/29] feat(game): add count feature (add JudgeService)

---
 src/main/java/domain/Numbers.java       |  4 ++++
 src/main/java/service/JudgeService.java | 19 ++++++++++++++++++-
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/src/main/java/domain/Numbers.java b/src/main/java/domain/Numbers.java
index 3ebccaca..5413e6c8 100644
--- a/src/main/java/domain/Numbers.java
+++ b/src/main/java/domain/Numbers.java
@@ -27,4 +27,8 @@ public int get(int index) {
     public boolean contains(int number) {
         return numbers.contains(number);
     }
+
+    public int size() {
+        return numbers.size();
+    }
 }
\ No newline at end of file
diff --git a/src/main/java/service/JudgeService.java b/src/main/java/service/JudgeService.java
index df9dbeb1..563829c7 100644
--- a/src/main/java/service/JudgeService.java
+++ b/src/main/java/service/JudgeService.java
@@ -1,5 +1,22 @@
 package service;
 
+import domain.JudgeCount;
+import domain.Numbers;
+
 public class JudgeService {
-    public
+    public JudgeCount judge(Numbers answer, Numbers guess) {
+        int ball = 0;
+        int strike = 0;
+        for (int i = 0; i < answer.size(); i++) {
+            int g = guess.get(i);
+            if (g == answer.get(i)) {
+                strike++;
+                continue;
+            }
+            if (answer.contains(g)) {
+                ball++;
+            }
+        }
+        return new JudgeCount(ball, strike);
+    }
 }

From 9a950e9fe8261aee6dd0249b31cdefb08c88266c Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Sun, 1 Feb 2026 23:13:24 +0900
Subject: [PATCH 12/29] feat(add): add get user input (add InputView)

---
 src/main/java/view/InputView.java | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/src/main/java/view/InputView.java b/src/main/java/view/InputView.java
index bc185bd1..4b78a275 100644
--- a/src/main/java/view/InputView.java
+++ b/src/main/java/view/InputView.java
@@ -1,13 +1,36 @@
 package view;
 
+import util.InputValidator;
+
 import java.util.Scanner;
 
 public class InputView {
+    private static final String GUESS_PROMPT = "숫자를 입력해주세요 : ";
+    private static final String RESTART_PROMPT = "게임을 새로 시작하려면 1, 종료하려면 2를 입력하세요.";
     private static final Scanner scanner = new Scanner(System.in);
 
     public String readGuess() {
-        System.out.print("숫자를 입력해 주세요: ");
-        return scanner.nextLine();
+        while (true) {
+            System.out.print("숫자를 입력해주세요 : ");
+            String input = scanner.nextLine().trim();
+            String error = InputValidator.guessError(input);
+            if (error == null) {
+                return input;
+            }
+            System.out.println(error);
+        }
+    }
+
+    public int readRestartCommand() {
+        while (true) {
+            System.out.println("게임을 새로 시작하려면 1, 종료하려면 2를 입력하세요.");
+            String input = scanner.nextLine().trim();
+            String error = InputValidator.restartError(input);
+            if (error == null) {
+                return Integer.parseInt(input);
+            }
+            System.out.println(error);
+        }
     }
 
 

From 04d4bd6772262587a4106af670bf93f6752995b4 Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Sun, 1 Feb 2026 23:15:55 +0900
Subject: [PATCH 13/29] refactor: inputview variable

---
 src/main/java/view/InputView.java | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/main/java/view/InputView.java b/src/main/java/view/InputView.java
index 4b78a275..c9c302c2 100644
--- a/src/main/java/view/InputView.java
+++ b/src/main/java/view/InputView.java
@@ -11,7 +11,7 @@ public class InputView {
 
     public String readGuess() {
         while (true) {
-            System.out.print("숫자를 입력해주세요 : ");
+            System.out.print(GUESS_PROMPT);
             String input = scanner.nextLine().trim();
             String error = InputValidator.guessError(input);
             if (error == null) {
@@ -23,7 +23,7 @@ public String readGuess() {
 
     public int readRestartCommand() {
         while (true) {
-            System.out.println("게임을 새로 시작하려면 1, 종료하려면 2를 입력하세요.");
+            System.out.println(RESTART_PROMPT);
             String input = scanner.nextLine().trim();
             String error = InputValidator.restartError(input);
             if (error == null) {

From 0f7bb29a4421d89a9e1541a02e8c7805ca16a937 Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Sun, 1 Feb 2026 23:19:25 +0900
Subject: [PATCH 14/29] refactor: InputView delete repetition

---
 src/main/java/view/InputView.java | 25 +++++++++++--------------
 1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/src/main/java/view/InputView.java b/src/main/java/view/InputView.java
index c9c302c2..b2ce1241 100644
--- a/src/main/java/view/InputView.java
+++ b/src/main/java/view/InputView.java
@@ -3,6 +3,7 @@
 import util.InputValidator;
 
 import java.util.Scanner;
+import java.util.function.Function;
 
 public class InputView {
     private static final String GUESS_PROMPT = "숫자를 입력해주세요 : ";
@@ -10,28 +11,24 @@ public class InputView {
     private static final Scanner scanner = new Scanner(System.in);
 
     public String readGuess() {
-        while (true) {
-            System.out.print(GUESS_PROMPT);
-            String input = scanner.nextLine().trim();
-            String error = InputValidator.guessError(input);
-            if (error == null) {
-                return input;
-            }
-            System.out.println(error);
-        }
+        return readUntilValid(GUESS_PROMPT, InputValidator::guessError);
     }
 
     public int readRestartCommand() {
+        String input = readUntilValid(RESTART_PROMPT, InputValidator::restartError);
+        return Integer.parseInt(input);
+    }
+
+    private String readUntilValid(String prompt, Function<String, String> validator) {
         while (true) {
-            System.out.println(RESTART_PROMPT);
+            System.out.println(prompt);
             String input = scanner.nextLine().trim();
-            String error = InputValidator.restartError(input);
+            String error = validator.apply(input);
+
             if (error == null) {
-                return Integer.parseInt(input);
+                return input;
             }
             System.out.println(error);
         }
     }
-
-
 }

From c8a2119ce4f38a0b7c5b0bdae576ab88b88962e3 Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Sun, 1 Feb 2026 23:28:59 +0900
Subject: [PATCH 15/29] feat(game): add playing game service (add GameService)

---
 src/main/java/service/GameService.java | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/src/main/java/service/GameService.java b/src/main/java/service/GameService.java
index b7dfec2d..c20a98c6 100644
--- a/src/main/java/service/GameService.java
+++ b/src/main/java/service/GameService.java
@@ -1,16 +1,33 @@
 package service;
 
+import domain.JudgeCount;
 import domain.Numbers;
 
 public class GameService {
     private final RandomNumberGenerator randomNumberGenerator;
+    private final JudgeService judgeService;
+
     private Numbers answer;
+    private JudgeCount lastCount;
 
-    public GameService(RandomNumberGenerator randomNumberGenerator) {
+    public GameService(RandomNumberGenerator randomNumberGenerator, JudgeService judgeService) {
         this.randomNumberGenerator = randomNumberGenerator;
+        this.judgeService = judgeService;
     }
 
     public void startNewGame() {
         answer = randomNumberGenerator.numberGenerate();
+        lastCount = null;
+    }
+
+    public JudgeCount play(String guessInput) {
+        JudgeCount count = judgeService.judge(answer, Numbers.from(guessInput));
+        lastCount = count;
+        return count;
+    }
+
+    public boolean isGameOver() {
+        if (lastCount == null) return false;
+        return lastCount.isThreeStrikes();
     }
 }

From 99883cb3d8c071499d92505cd59d67ff586432ab Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Sun, 1 Feb 2026 23:34:49 +0900
Subject: [PATCH 16/29] feat(game): add print result message

---
 src/main/java/view/OutputView.java | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/main/java/view/OutputView.java b/src/main/java/view/OutputView.java
index f62ee0d4..dd038a6b 100644
--- a/src/main/java/view/OutputView.java
+++ b/src/main/java/view/OutputView.java
@@ -1,7 +1,20 @@
 package view;
 
+import domain.JudgeCount;
+
 public class OutputView {
+    private static final String START_MESSAGE = "숫자 야구 게임 시작";
+    private static final String END_MESSAGE = "3개의 숫자를 모두 맞히셨습니다! 게임 끝";
+
     public void printStartMessage() {
-        System.out.println("숫자 야구 게임 시작");
+        System.out.println(START_MESSAGE);
+    }
+
+    public void printResult(JudgeCount count) {
+        System.out.println(count.toMessage());
+    }
+
+    public void printGameEndMessage() {
+        System.out.println(END_MESSAGE);
     }
 }

From 745bd4c34427ce3df0f581b4d335971b50335b4f Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Sun, 1 Feb 2026 23:59:17 +0900
Subject: [PATCH 17/29] =?UTF-8?q?feat(game)=20game=20=ED=95=9C=20=ED=9D=90?=
 =?UTF-8?q?=EB=A6=84=20=EC=A7=84=ED=96=89=20=EA=B5=AC=ED=98=84?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/main/java/Application.java               |  4 ++-
 src/main/java/controller/GameController.java | 28 +++++++++++++++++++-
 src/main/java/view/InputView.java            |  1 +
 3 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/src/main/java/Application.java b/src/main/java/Application.java
index 69560bc3..ddc4ab1c 100644
--- a/src/main/java/Application.java
+++ b/src/main/java/Application.java
@@ -1,5 +1,6 @@
 import controller.GameController;
 import service.GameService;
+import service.JudgeService;
 import view.InputView;
 import view.OutputView;
 import service.RandomNumberGenerator;
@@ -9,7 +10,8 @@ public static void main(String[] args) {
         InputView inputView = new InputView();
         OutputView outputView = new OutputView();
         GameService gameService = new GameService(
-                new RandomNumberGenerator()
+                new RandomNumberGenerator(),
+                new JudgeService()
         );
 
         new GameController(inputView, outputView, gameService).run();
diff --git a/src/main/java/controller/GameController.java b/src/main/java/controller/GameController.java
index aa513f34..56a434ba 100644
--- a/src/main/java/controller/GameController.java
+++ b/src/main/java/controller/GameController.java
@@ -1,5 +1,6 @@
 package controller;
 
+import domain.JudgeCount;
 import domain.Numbers;
 import service.GameService;
 import view.InputView;
@@ -18,6 +19,31 @@ public GameController(InputView inputView, OutputView outputView, GameService ga
 
     public void run() {
         outputView.printStartMessage();
-        String guess = inputView.readGuess();
+        while (true) {
+            playGame();
+            if (shouldStop()) {
+                return;
+            }
+        }
+    }
+
+    private void playGame() {
+        gameService.startNewGame();
+        playUntilWin();
+    }
+
+    private void playUntilWin() {
+        while (true) {
+            JudgeCount count = gameService.play(inputView.readGuess());
+            outputView.printResult(count);
+            if (count.isThreeStrikes()) {
+                break;
+            }
+        }
+        outputView.printGameEndMessage();
+    }
+
+    private boolean shouldStop() {
+        return inputView.readRestartCommand() == 2;
     }
 }
diff --git a/src/main/java/view/InputView.java b/src/main/java/view/InputView.java
index b2ce1241..49e3f13d 100644
--- a/src/main/java/view/InputView.java
+++ b/src/main/java/view/InputView.java
@@ -8,6 +8,7 @@
 public class InputView {
     private static final String GUESS_PROMPT = "숫자를 입력해주세요 : ";
     private static final String RESTART_PROMPT = "게임을 새로 시작하려면 1, 종료하려면 2를 입력하세요.";
+
     private static final Scanner scanner = new Scanner(System.in);
 
     public String readGuess() {

From b27b6a076d44dc6602b646a71e3471ff8557d9cb Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Mon, 2 Feb 2026 00:14:08 +0900
Subject: [PATCH 18/29] =?UTF-8?q?fix(input):=20prompt=20print=20println=20?=
 =?UTF-8?q?=EA=B5=AC=EB=B6=84?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/main/java/view/InputView.java | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/main/java/view/InputView.java b/src/main/java/view/InputView.java
index 49e3f13d..240930de 100644
--- a/src/main/java/view/InputView.java
+++ b/src/main/java/view/InputView.java
@@ -3,6 +3,7 @@
 import util.InputValidator;
 
 import java.util.Scanner;
+import java.util.function.Consumer;
 import java.util.function.Function;
 
 public class InputView {
@@ -12,17 +13,17 @@ public class InputView {
     private static final Scanner scanner = new Scanner(System.in);
 
     public String readGuess() {
-        return readUntilValid(GUESS_PROMPT, InputValidator::guessError);
+        return readUntilValid(GUESS_PROMPT, System.out::print, InputValidator::guessError);
     }
 
     public int readRestartCommand() {
-        String input = readUntilValid(RESTART_PROMPT, InputValidator::restartError);
+        String input = readUntilValid(RESTART_PROMPT, System.out::println, InputValidator::restartError);
         return Integer.parseInt(input);
     }
 
-    private String readUntilValid(String prompt, Function<String, String> validator) {
+    private String readUntilValid(String prompt, Consumer<String> printer, Function<String, String> validator) {
         while (true) {
-            System.out.println(prompt);
+            printer.accept(prompt);
             String input = scanner.nextLine().trim();
             String error = validator.apply(input);
 

From 0931c9a2a9dd821a0cd5a093c692d99b8d4e251f Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Mon, 2 Feb 2026 17:45:27 +0900
Subject: [PATCH 19/29] feat(error): add error handling function at Numbers
 from

---
 src/main/java/controller/GameController.java               | 5 +----
 src/main/java/domain/Numbers.java                          | 6 ++++++
 src/main/java/util/{InputValidator.java => Validator.java} | 2 +-
 src/main/java/view/InputView.java                          | 7 ++++---
 4 files changed, 12 insertions(+), 8 deletions(-)
 rename src/main/java/util/{InputValidator.java => Validator.java} (98%)

diff --git a/src/main/java/controller/GameController.java b/src/main/java/controller/GameController.java
index 56a434ba..0b56658d 100644
--- a/src/main/java/controller/GameController.java
+++ b/src/main/java/controller/GameController.java
@@ -33,12 +33,9 @@ private void playGame() {
     }
 
     private void playUntilWin() {
-        while (true) {
+        while (!gameService.isGameOver()) {
             JudgeCount count = gameService.play(inputView.readGuess());
             outputView.printResult(count);
-            if (count.isThreeStrikes()) {
-                break;
-            }
         }
         outputView.printGameEndMessage();
     }
diff --git a/src/main/java/domain/Numbers.java b/src/main/java/domain/Numbers.java
index 5413e6c8..c380136c 100644
--- a/src/main/java/domain/Numbers.java
+++ b/src/main/java/domain/Numbers.java
@@ -1,5 +1,7 @@
 package domain;
 
+import util.Validator;
+
 import java.util.ArrayList;
 import java.util.List;
 
@@ -11,6 +13,10 @@ private Numbers(List<Integer> numbers) {
     }
 
     public static Numbers from(String input) {
+        String error = Validator.guessError(input);
+        if (error != null) {
+            throw new IllegalArgumentException(error);
+        }
         return new Numbers(parse(input));
     }
 
diff --git a/src/main/java/util/InputValidator.java b/src/main/java/util/Validator.java
similarity index 98%
rename from src/main/java/util/InputValidator.java
rename to src/main/java/util/Validator.java
index 689444fb..bbf864ae 100644
--- a/src/main/java/util/InputValidator.java
+++ b/src/main/java/util/Validator.java
@@ -3,7 +3,7 @@
 import java.util.HashSet;
 import java.util.Set;
 
-public class InputValidator {
+public class Validator {
     private static final String ERROR_PREFIX = "[ERROR] ";
     private static final int INPUT_LENGTH = 3;
     private static final String RESTART_CODE = "1";
diff --git a/src/main/java/view/InputView.java b/src/main/java/view/InputView.java
index 240930de..a9addb74 100644
--- a/src/main/java/view/InputView.java
+++ b/src/main/java/view/InputView.java
@@ -1,6 +1,6 @@
 package view;
 
-import util.InputValidator;
+import util.Validator;
 
 import java.util.Scanner;
 import java.util.function.Consumer;
@@ -13,11 +13,11 @@ public class InputView {
     private static final Scanner scanner = new Scanner(System.in);
 
     public String readGuess() {
-        return readUntilValid(GUESS_PROMPT, System.out::print, InputValidator::guessError);
+        return readUntilValid(GUESS_PROMPT, System.out::print, Validator::guessError);
     }
 
     public int readRestartCommand() {
-        String input = readUntilValid(RESTART_PROMPT, System.out::println, InputValidator::restartError);
+        String input = readUntilValid(RESTART_PROMPT, System.out::println, Validator::restartError);
         return Integer.parseInt(input);
     }
 
@@ -31,6 +31,7 @@ private String readUntilValid(String prompt, Consumer<String> printer, Function<
                 return input;
             }
             System.out.println(error);
+//            throw new IllegalArgumentException(error);
         }
     }
 }

From 9221ebebc8e2556a4e2bd4ee1974585ea40d0dd7 Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Mon, 2 Feb 2026 17:50:42 +0900
Subject: [PATCH 20/29] feat(domain): add new domain(Number)

---
 src/main/java/domain/Number.java  | 25 +++++++++++++++++++++++++
 src/main/java/util/Validator.java | 18 +++++++++++++-----
 src/main/java/view/InputView.java |  1 -
 3 files changed, 38 insertions(+), 6 deletions(-)
 create mode 100644 src/main/java/domain/Number.java

diff --git a/src/main/java/domain/Number.java b/src/main/java/domain/Number.java
new file mode 100644
index 00000000..b8c80a1b
--- /dev/null
+++ b/src/main/java/domain/Number.java
@@ -0,0 +1,25 @@
+package domain;
+
+import util.Validator;
+
+public class Number {
+    private final int value;
+
+    private Number(int value) {
+        this.value = value;
+    }
+
+    public static Number fromChar(char c) {
+        String error = Validator.numberError(c);
+        if (error != null) throw new IllegalArgumentException(error);
+        return new Number(c - '0');
+    }
+
+    public int value() {
+        return value;
+    }
+
+    public boolean same(int other) {
+        return value == other;
+    }
+}
diff --git a/src/main/java/util/Validator.java b/src/main/java/util/Validator.java
index bbf864ae..fc5b5911 100644
--- a/src/main/java/util/Validator.java
+++ b/src/main/java/util/Validator.java
@@ -20,11 +20,9 @@ private static String validateCharacters(String input) {
         Set<Character> uniqueChars = new HashSet<>();
 
         for (char c : input.toCharArray()) {
-            if (!Character.isDigit(c)) {
-                return errorMessage("숫자만 입력해야 합니다.");
-            }
-            if (c == '0') {
-                return errorMessage("0은 사용할 수 없습니다.");
+            String error = numberError(c);
+            if (error != null) {
+                return error;
             }
             if (!uniqueChars.add(c)) {
                 return errorMessage("중복된 숫자는 사용할 수 없습니다.");
@@ -33,6 +31,16 @@ private static String validateCharacters(String input) {
         return null;
     }
 
+    public static String numberError(char c) {
+        if (!Character.isDigit(c)) {
+            return errorMessage("숫자만 입력해야 합니다.");
+        }
+        if (c == '0') {
+            return errorMessage("0은 사용할 수 없습니다.");
+        }
+        return null;
+    }
+
     public static String restartError(String input) {
         if (RESTART_CODE.equals(input) || EXIT_CODE.equals(input)) {
             return null;
diff --git a/src/main/java/view/InputView.java b/src/main/java/view/InputView.java
index a9addb74..f803d6cd 100644
--- a/src/main/java/view/InputView.java
+++ b/src/main/java/view/InputView.java
@@ -31,7 +31,6 @@ private String readUntilValid(String prompt, Consumer<String> printer, Function<
                 return input;
             }
             System.out.println(error);
-//            throw new IllegalArgumentException(error);
         }
     }
 }

From 2e5539cf3f43617a0d63b7e660302703714185bf Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Mon, 2 Feb 2026 18:37:30 +0900
Subject: [PATCH 21/29] feat(domain): Number domain apply

---
 src/main/java/domain/Numbers.java | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/src/main/java/domain/Numbers.java b/src/main/java/domain/Numbers.java
index c380136c..2b33fa34 100644
--- a/src/main/java/domain/Numbers.java
+++ b/src/main/java/domain/Numbers.java
@@ -6,9 +6,10 @@
 import java.util.List;
 
 public class Numbers {
-    private final List<Integer> numbers;
+    private static final int LENGTH = 3;
+    private final List<Number> numbers;
 
-    private Numbers(List<Integer> numbers) {
+    private Numbers(List<Number> numbers) {
         this.numbers = numbers;
     }
 
@@ -20,18 +21,25 @@ public static Numbers from(String input) {
         return new Numbers(parse(input));
     }
 
-    private static List<Integer> parse(String input) {
-        List<Integer> nums = new ArrayList<>(3);
-        for (int i = 0; i < 3; i++) nums.add(input.charAt(i) - '0');
+    private static List<Number> parse(String input) {
+        List<Number> nums = new ArrayList<>(LENGTH);
+        for (char c : input.toCharArray()) {
+            nums.add(Number.fromChar(c));
+        }
         return nums;
     }
 
     public int get(int index) {
-        return numbers.get(index);
+        return numbers.get(index).value();
     }
 
     public boolean contains(int number) {
-        return numbers.contains(number);
+        for (Number n : numbers) {
+            if (n.same(number)) {
+                return true;
+            }
+        }
+        return false;
     }
 
     public int size() {

From b2678eee3e0c1cd3fe4cab1a5e25cd4981e319fa Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Mon, 2 Feb 2026 20:02:42 +0900
Subject: [PATCH 22/29] =?UTF-8?q?test:=20testcase=20=EC=B6=94=EA=B0=80?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/main/java/controller/GameController.java |  1 -
 src/test/java/domain/JudgeCountTest.java     | 42 +++++++++++++++++
 src/test/java/domain/NumberTest.java         | 31 +++++++++++++
 src/test/java/domain/NumbersTest.java        | 48 ++++++++++++++++++++
 src/test/java/service/JudgeServiceTest.java  | 35 ++++++++++++++
 src/test/java/util/ValidatorTest.java        | 39 ++++++++++++++++
 6 files changed, 195 insertions(+), 1 deletion(-)
 create mode 100644 src/test/java/domain/JudgeCountTest.java
 create mode 100644 src/test/java/domain/NumberTest.java
 create mode 100644 src/test/java/domain/NumbersTest.java
 create mode 100644 src/test/java/service/JudgeServiceTest.java
 create mode 100644 src/test/java/util/ValidatorTest.java

diff --git a/src/main/java/controller/GameController.java b/src/main/java/controller/GameController.java
index 0b56658d..8dae0260 100644
--- a/src/main/java/controller/GameController.java
+++ b/src/main/java/controller/GameController.java
@@ -1,7 +1,6 @@
 package controller;
 
 import domain.JudgeCount;
-import domain.Numbers;
 import service.GameService;
 import view.InputView;
 import view.OutputView;
diff --git a/src/test/java/domain/JudgeCountTest.java b/src/test/java/domain/JudgeCountTest.java
new file mode 100644
index 00000000..f791abdc
--- /dev/null
+++ b/src/test/java/domain/JudgeCountTest.java
@@ -0,0 +1,42 @@
+package domain;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class JudgeCountTest {
+    @Test
+    void toMessageNothing() {
+        JudgeCount count = new JudgeCount(0, 0);
+
+        assertThat(count.toMessage()).isEqualTo("낫싱");
+    }
+
+    @Test
+    void toMessageBallOnly() {
+        JudgeCount count = new JudgeCount(2, 0);
+
+        assertThat(count.toMessage()).isEqualTo("2볼");
+    }
+
+    @Test
+    void toMessageStrikeOnly() {
+        JudgeCount count = new JudgeCount(0, 1);
+
+        assertThat(count.toMessage()).isEqualTo("1스트라이크");
+    }
+
+    @Test
+    void toMessageBallAndStrike() {
+        JudgeCount count = new JudgeCount(1, 2);
+
+        assertThat(count.toMessage()).isEqualTo("1볼 2스트라이크");
+    }
+
+    @Test
+    void isThreeStrikesTrueWhenThreeStrikes() {
+        JudgeCount count = new JudgeCount(0, 3);
+
+        assertThat(count.isThreeStrikes()).isTrue();
+    }
+}
diff --git a/src/test/java/domain/NumberTest.java b/src/test/java/domain/NumberTest.java
new file mode 100644
index 00000000..f4230420
--- /dev/null
+++ b/src/test/java/domain/NumberTest.java
@@ -0,0 +1,31 @@
+package domain;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+class NumberTest {
+    @Test
+    void fromCharValidDigitCreatesNumber() {
+        Number number = Number.fromChar('7');
+
+        assertThat(number.value()).isEqualTo(7);
+        assertThat(number.same(7)).isTrue();
+        assertThat(number.same(5)).isFalse();
+    }
+
+    @Test
+    void fromCharNonDigitThrowsException() {
+        assertThatThrownBy(() -> Number.fromChar('a'))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessage("[ERROR] 숫자만 입력해야 합니다.");
+    }
+
+    @Test
+    void fromCharZeroThrowsException() {
+        assertThatThrownBy(() -> Number.fromChar('0'))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessage("[ERROR] 0은 사용할 수 없습니다.");
+    }
+}
diff --git a/src/test/java/domain/NumbersTest.java b/src/test/java/domain/NumbersTest.java
new file mode 100644
index 00000000..4fa7bd07
--- /dev/null
+++ b/src/test/java/domain/NumbersTest.java
@@ -0,0 +1,48 @@
+package domain;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+class NumbersTest {
+    @Test
+    void fromValidInputParsesNumbers() {
+        Numbers numbers = Numbers.from("123");
+
+        assertThat(numbers.size()).isEqualTo(3);
+        assertThat(numbers.get(0)).isEqualTo(1);
+        assertThat(numbers.get(1)).isEqualTo(2);
+        assertThat(numbers.get(2)).isEqualTo(3);
+        assertThat(numbers.contains(2)).isTrue();
+        assertThat(numbers.contains(9)).isFalse();
+    }
+
+    @Test
+    void fromWrongLengthThrowsException() {
+        assertThatThrownBy(() -> Numbers.from("12"))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessage("[ERROR] 3자여야 합니다.");
+    }
+
+    @Test
+    void fromDuplicateDigitsThrowsException() {
+        assertThatThrownBy(() -> Numbers.from("112"))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessage("[ERROR] 중복된 숫자는 사용할 수 없습니다.");
+    }
+
+    @Test
+    void fromNonDigitThrowsException() {
+        assertThatThrownBy(() -> Numbers.from("12a"))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessage("[ERROR] 숫자만 입력해야 합니다.");
+    }
+
+    @Test
+    void fromContainsZeroThrowsException() {
+        assertThatThrownBy(() -> Numbers.from("120"))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessage("[ERROR] 0은 사용할 수 없습니다.");
+    }
+}
diff --git a/src/test/java/service/JudgeServiceTest.java b/src/test/java/service/JudgeServiceTest.java
new file mode 100644
index 00000000..541d56cc
--- /dev/null
+++ b/src/test/java/service/JudgeServiceTest.java
@@ -0,0 +1,35 @@
+package service;
+
+import domain.Numbers;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class JudgeServiceTest {
+    private final JudgeService judgeService = new JudgeService();
+
+    @Test
+    void judgeAllStrikes() {
+        Numbers answer = Numbers.from("123");
+        Numbers guess = Numbers.from("123");
+
+        assertThat(judgeService.judge(answer, guess).isThreeStrikes()).isTrue();
+        assertThat(judgeService.judge(answer, guess).toMessage()).isEqualTo("3스트라이크");
+    }
+
+    @Test
+    void judgeBallAndStrike() {
+        Numbers answer = Numbers.from("123");
+        Numbers guess = Numbers.from("132");
+
+        assertThat(judgeService.judge(answer, guess).toMessage()).isEqualTo("2볼 1스트라이크");
+    }
+
+    @Test
+    void judgeNothing() {
+        Numbers answer = Numbers.from("123");
+        Numbers guess = Numbers.from("456");
+
+        assertThat(judgeService.judge(answer, guess).toMessage()).isEqualTo("낫싱");
+    }
+}
diff --git a/src/test/java/util/ValidatorTest.java b/src/test/java/util/ValidatorTest.java
new file mode 100644
index 00000000..9b45a9af
--- /dev/null
+++ b/src/test/java/util/ValidatorTest.java
@@ -0,0 +1,39 @@
+package util;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class ValidatorTest {
+    @Test
+    void guessErrorWrongLength() {
+        assertThat(Validator.guessError("12")).isEqualTo("[ERROR] 3자여야 합니다.");
+    }
+
+    @Test
+    void guessErrorDuplicateDigits() {
+        assertThat(Validator.guessError("112")).isEqualTo("[ERROR] 중복된 숫자는 사용할 수 없습니다.");
+    }
+
+    @Test
+    void guessErrorNonDigit() {
+        assertThat(Validator.guessError("12a")).isEqualTo("[ERROR] 숫자만 입력해야 합니다.");
+    }
+
+    @Test
+    void numberErrorValidDigitReturnsNull() {
+        assertThat(Validator.numberError('7')).isNull();
+    }
+
+    @Test
+    void restartErrorValidInputsReturnNull() {
+        assertThat(Validator.restartError("1")).isNull();
+        assertThat(Validator.restartError("2")).isNull();
+    }
+
+    @Test
+    void restartErrorInvalidInputReturnsMessage() {
+        assertThat(Validator.restartError("3"))
+                .isEqualTo("[ERROR] 재시작은 1, 종료는 2만 입력 가능합니다.");
+    }
+}

From bf29632305c66218cf02bd1e413dd9a83949d62b Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Mon, 2 Feb 2026 20:12:19 +0900
Subject: [PATCH 23/29] refactor(view): refactor input output view separate
 roles

---
 src/main/java/controller/GameController.java | 8 ++++++--
 src/main/java/view/InputView.java            | 9 +++++----
 src/main/java/view/OutputView.java           | 4 ++++
 3 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/src/main/java/controller/GameController.java b/src/main/java/controller/GameController.java
index 8dae0260..48990b70 100644
--- a/src/main/java/controller/GameController.java
+++ b/src/main/java/controller/GameController.java
@@ -33,8 +33,12 @@ private void playGame() {
 
     private void playUntilWin() {
         while (!gameService.isGameOver()) {
-            JudgeCount count = gameService.play(inputView.readGuess());
-            outputView.printResult(count);
+            try {
+                JudgeCount count = gameService.play(inputView.readGuess());
+                outputView.printResult(count);
+            } catch (IllegalArgumentException e) {
+                outputView.printError(e.getMessage());
+            }
         }
         outputView.printGameEndMessage();
     }
diff --git a/src/main/java/view/InputView.java b/src/main/java/view/InputView.java
index f803d6cd..66fdf585 100644
--- a/src/main/java/view/InputView.java
+++ b/src/main/java/view/InputView.java
@@ -13,17 +13,18 @@ public class InputView {
     private static final Scanner scanner = new Scanner(System.in);
 
     public String readGuess() {
-        return readUntilValid(GUESS_PROMPT, System.out::print, Validator::guessError);
+        System.out.print(GUESS_PROMPT);
+        return scanner.nextLine().trim();
     }
 
     public int readRestartCommand() {
-        String input = readUntilValid(RESTART_PROMPT, System.out::println, Validator::restartError);
+        String input = readUntilValid(System.out::println, Validator::restartError);
         return Integer.parseInt(input);
     }
 
-    private String readUntilValid(String prompt, Consumer<String> printer, Function<String, String> validator) {
+    private String readUntilValid(Consumer<String> printer, Function<String, String> validator) {
         while (true) {
-            printer.accept(prompt);
+            printer.accept(InputView.RESTART_PROMPT);
             String input = scanner.nextLine().trim();
             String error = validator.apply(input);
 
diff --git a/src/main/java/view/OutputView.java b/src/main/java/view/OutputView.java
index dd038a6b..2767ba11 100644
--- a/src/main/java/view/OutputView.java
+++ b/src/main/java/view/OutputView.java
@@ -17,4 +17,8 @@ public void printResult(JudgeCount count) {
     public void printGameEndMessage() {
         System.out.println(END_MESSAGE);
     }
+
+    public void printError(String message) {
+        System.out.println(message);
+    }
 }

From 7b9b633f041f9459d64153c5a1a66421f70adf1f Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Mon, 2 Feb 2026 20:26:07 +0900
Subject: [PATCH 24/29] refactor: add game domain

---
 src/main/java/domain/Game.java         | 24 ++++++++++++++++++++++++
 src/main/java/service/GameService.java | 15 ++++++---------
 2 files changed, 30 insertions(+), 9 deletions(-)
 create mode 100644 src/main/java/domain/Game.java

diff --git a/src/main/java/domain/Game.java b/src/main/java/domain/Game.java
new file mode 100644
index 00000000..d7b37fd6
--- /dev/null
+++ b/src/main/java/domain/Game.java
@@ -0,0 +1,24 @@
+package domain;
+
+import service.JudgeService;
+
+public class Game {
+    private final Numbers answer;
+    private final JudgeService judgeService;
+    private JudgeCount lastCount;
+
+    public Game(Numbers answer, JudgeService judgeService) {
+        this.answer = answer;
+        this.judgeService = judgeService;
+    }
+
+    public JudgeCount play(String guessInput) {
+        JudgeCount count = judgeService.judge(answer, Numbers.from(guessInput));
+        lastCount = count;
+        return count;
+    }
+
+    public boolean isOver() {
+        return lastCount != null && lastCount.isThreeStrikes();
+    }
+}
diff --git a/src/main/java/service/GameService.java b/src/main/java/service/GameService.java
index c20a98c6..285eab97 100644
--- a/src/main/java/service/GameService.java
+++ b/src/main/java/service/GameService.java
@@ -1,5 +1,6 @@
 package service;
 
+import domain.Game;
 import domain.JudgeCount;
 import domain.Numbers;
 
@@ -7,8 +8,7 @@ public class GameService {
     private final RandomNumberGenerator randomNumberGenerator;
     private final JudgeService judgeService;
 
-    private Numbers answer;
-    private JudgeCount lastCount;
+    private Game currentGame;
 
     public GameService(RandomNumberGenerator randomNumberGenerator, JudgeService judgeService) {
         this.randomNumberGenerator = randomNumberGenerator;
@@ -16,18 +16,15 @@ public GameService(RandomNumberGenerator randomNumberGenerator, JudgeService jud
     }
 
     public void startNewGame() {
-        answer = randomNumberGenerator.numberGenerate();
-        lastCount = null;
+        Numbers answer = randomNumberGenerator.numberGenerate();
+        currentGame = new Game(answer, judgeService);
     }
 
     public JudgeCount play(String guessInput) {
-        JudgeCount count = judgeService.judge(answer, Numbers.from(guessInput));
-        lastCount = count;
-        return count;
+        return currentGame.play(guessInput);
     }
 
     public boolean isGameOver() {
-        if (lastCount == null) return false;
-        return lastCount.isThreeStrikes();
+        return currentGame.isOver();
     }
 }

From 58f2b8de4d8fce2b427173ba9965425b6475ef1a Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Mon, 2 Feb 2026 20:44:39 +0900
Subject: [PATCH 25/29] =?UTF-8?q?refactor(domain):=20judgeservice=20?=
 =?UTF-8?q?=EC=A0=9C=EA=B1=B0=20numbers=EC=97=90=20=EA=B8=B0=EB=8A=A5=20?=
 =?UTF-8?q?=EC=B6=94=EA=B0=80?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/main/java/Application.java                |  4 +---
 src/main/java/domain/Game.java                |  8 ++-----
 src/main/java/domain/Numbers.java             | 18 ++++++++++++++-
 src/main/java/service/GameService.java        |  7 ++----
 src/main/java/service/JudgeService.java       | 22 -------------------
 .../NumbersJudgeTest.java}                    | 15 +++++--------
 6 files changed, 28 insertions(+), 46 deletions(-)
 delete mode 100644 src/main/java/service/JudgeService.java
 rename src/test/java/{service/JudgeServiceTest.java => domain/NumbersJudgeTest.java} (50%)

diff --git a/src/main/java/Application.java b/src/main/java/Application.java
index ddc4ab1c..69560bc3 100644
--- a/src/main/java/Application.java
+++ b/src/main/java/Application.java
@@ -1,6 +1,5 @@
 import controller.GameController;
 import service.GameService;
-import service.JudgeService;
 import view.InputView;
 import view.OutputView;
 import service.RandomNumberGenerator;
@@ -10,8 +9,7 @@ public static void main(String[] args) {
         InputView inputView = new InputView();
         OutputView outputView = new OutputView();
         GameService gameService = new GameService(
-                new RandomNumberGenerator(),
-                new JudgeService()
+                new RandomNumberGenerator()
         );
 
         new GameController(inputView, outputView, gameService).run();
diff --git a/src/main/java/domain/Game.java b/src/main/java/domain/Game.java
index d7b37fd6..219a5113 100644
--- a/src/main/java/domain/Game.java
+++ b/src/main/java/domain/Game.java
@@ -1,19 +1,15 @@
 package domain;
 
-import service.JudgeService;
-
 public class Game {
     private final Numbers answer;
-    private final JudgeService judgeService;
     private JudgeCount lastCount;
 
-    public Game(Numbers answer, JudgeService judgeService) {
+    public Game(Numbers answer) {
         this.answer = answer;
-        this.judgeService = judgeService;
     }
 
     public JudgeCount play(String guessInput) {
-        JudgeCount count = judgeService.judge(answer, Numbers.from(guessInput));
+        JudgeCount count = answer.judge(Numbers.from(guessInput));
         lastCount = count;
         return count;
     }
diff --git a/src/main/java/domain/Numbers.java b/src/main/java/domain/Numbers.java
index 2b33fa34..af05168e 100644
--- a/src/main/java/domain/Numbers.java
+++ b/src/main/java/domain/Numbers.java
@@ -45,4 +45,20 @@ public boolean contains(int number) {
     public int size() {
         return numbers.size();
     }
-}
\ No newline at end of file
+
+    public JudgeCount judge(Numbers guess) {
+        int ball = 0;
+        int strike = 0;
+        for (int i = 0; i < size(); i++) {
+            int g = guess.get(i);
+            if (g == get(i)) {
+                strike++;
+                continue;
+            }
+            if (contains(g)) {
+                ball++;
+            }
+        }
+        return new JudgeCount(ball, strike);
+    }
+}
diff --git a/src/main/java/service/GameService.java b/src/main/java/service/GameService.java
index 285eab97..38523283 100644
--- a/src/main/java/service/GameService.java
+++ b/src/main/java/service/GameService.java
@@ -6,18 +6,15 @@
 
 public class GameService {
     private final RandomNumberGenerator randomNumberGenerator;
-    private final JudgeService judgeService;
-
     private Game currentGame;
 
-    public GameService(RandomNumberGenerator randomNumberGenerator, JudgeService judgeService) {
+    public GameService(RandomNumberGenerator randomNumberGenerator) {
         this.randomNumberGenerator = randomNumberGenerator;
-        this.judgeService = judgeService;
     }
 
     public void startNewGame() {
         Numbers answer = randomNumberGenerator.numberGenerate();
-        currentGame = new Game(answer, judgeService);
+        currentGame = new Game(answer);
     }
 
     public JudgeCount play(String guessInput) {
diff --git a/src/main/java/service/JudgeService.java b/src/main/java/service/JudgeService.java
deleted file mode 100644
index 563829c7..00000000
--- a/src/main/java/service/JudgeService.java
+++ /dev/null
@@ -1,22 +0,0 @@
-package service;
-
-import domain.JudgeCount;
-import domain.Numbers;
-
-public class JudgeService {
-    public JudgeCount judge(Numbers answer, Numbers guess) {
-        int ball = 0;
-        int strike = 0;
-        for (int i = 0; i < answer.size(); i++) {
-            int g = guess.get(i);
-            if (g == answer.get(i)) {
-                strike++;
-                continue;
-            }
-            if (answer.contains(g)) {
-                ball++;
-            }
-        }
-        return new JudgeCount(ball, strike);
-    }
-}
diff --git a/src/test/java/service/JudgeServiceTest.java b/src/test/java/domain/NumbersJudgeTest.java
similarity index 50%
rename from src/test/java/service/JudgeServiceTest.java
rename to src/test/java/domain/NumbersJudgeTest.java
index 541d56cc..aebc92da 100644
--- a/src/test/java/service/JudgeServiceTest.java
+++ b/src/test/java/domain/NumbersJudgeTest.java
@@ -1,20 +1,17 @@
-package service;
+package domain;
 
-import domain.Numbers;
 import org.junit.jupiter.api.Test;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
-class JudgeServiceTest {
-    private final JudgeService judgeService = new JudgeService();
-
+class NumbersJudgeTest {
     @Test
     void judgeAllStrikes() {
         Numbers answer = Numbers.from("123");
         Numbers guess = Numbers.from("123");
 
-        assertThat(judgeService.judge(answer, guess).isThreeStrikes()).isTrue();
-        assertThat(judgeService.judge(answer, guess).toMessage()).isEqualTo("3스트라이크");
+        assertThat(answer.judge(guess).isThreeStrikes()).isTrue();
+        assertThat(answer.judge(guess).toMessage()).isEqualTo("3스트라이크");
     }
 
     @Test
@@ -22,7 +19,7 @@ void judgeBallAndStrike() {
         Numbers answer = Numbers.from("123");
         Numbers guess = Numbers.from("132");
 
-        assertThat(judgeService.judge(answer, guess).toMessage()).isEqualTo("2볼 1스트라이크");
+        assertThat(answer.judge(guess).toMessage()).isEqualTo("2볼 1스트라이크");
     }
 
     @Test
@@ -30,6 +27,6 @@ void judgeNothing() {
         Numbers answer = Numbers.from("123");
         Numbers guess = Numbers.from("456");
 
-        assertThat(judgeService.judge(answer, guess).toMessage()).isEqualTo("낫싱");
+        assertThat(answer.judge(guess).toMessage()).isEqualTo("낫싱");
     }
 }

From 9a74fae3bcee30e96c30c1fed2d7a016083bcc1b Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Mon, 2 Feb 2026 21:03:56 +0900
Subject: [PATCH 26/29] =?UTF-8?q?refactor:=20result=20=ED=91=9C=EC=8B=9C?=
 =?UTF-8?q?=20outputview=EB=A1=9C=20=EC=9D=B4=EB=8F=99?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/main/java/domain/JudgeCount.java       | 27 +---------------------
 src/main/java/view/OutputView.java         | 17 +++++++++++++-
 src/test/java/domain/JudgeCountTest.java   | 26 +++------------------
 src/test/java/domain/NumbersJudgeTest.java |  9 +++++---
 4 files changed, 26 insertions(+), 53 deletions(-)

diff --git a/src/main/java/domain/JudgeCount.java b/src/main/java/domain/JudgeCount.java
index a619876f..bde4e81c 100644
--- a/src/main/java/domain/JudgeCount.java
+++ b/src/main/java/domain/JudgeCount.java
@@ -1,33 +1,8 @@
 package domain;
 
-public class JudgeCount {
-    private final int ball;
-    private final int strike;
-
-    public JudgeCount(int ball, int strike) {
-        this.ball = ball;
-        this.strike = strike;
-    }
+public record JudgeCount(int ball, int strike) {
 
     public boolean isThreeStrikes() {
         return strike == 3;
     }
-
-    public String toMessage() {
-        if (ball == 0 && strike == 0) return "낫싱";
-        StringBuilder sb = new StringBuilder();
-        appendBall(sb);
-        appendStrike(sb);
-        return sb.toString().trim();
-    }
-
-    private void appendBall(StringBuilder sb) {
-        if (ball == 0) return;
-        sb.append(ball).append("볼 ");
-    }
-
-    private void appendStrike(StringBuilder sb) {
-        if (strike == 0) return;
-        sb.append(strike).append("스트라이크");
-    }
 }
diff --git a/src/main/java/view/OutputView.java b/src/main/java/view/OutputView.java
index 2767ba11..f595ede5 100644
--- a/src/main/java/view/OutputView.java
+++ b/src/main/java/view/OutputView.java
@@ -11,7 +11,7 @@ public void printStartMessage() {
     }
 
     public void printResult(JudgeCount count) {
-        System.out.println(count.toMessage());
+        System.out.println(formatResult(count));
     }
 
     public void printGameEndMessage() {
@@ -21,4 +21,19 @@ public void printGameEndMessage() {
     public void printError(String message) {
         System.out.println(message);
     }
+
+    private String formatResult(JudgeCount count) {
+        int ball = count.ball();
+        int strike = count.strike();
+        if (ball == 0 && strike == 0) return "낫싱";
+
+        StringBuilder sb = new StringBuilder();
+        if (ball > 0) {
+            sb.append(ball).append("볼 ");
+        }
+        if (strike > 0) {
+            sb.append(strike).append("스트라이크");
+        }
+        return sb.toString().trim();
+    }
 }
diff --git a/src/test/java/domain/JudgeCountTest.java b/src/test/java/domain/JudgeCountTest.java
index f791abdc..f7fa021e 100644
--- a/src/test/java/domain/JudgeCountTest.java
+++ b/src/test/java/domain/JudgeCountTest.java
@@ -6,31 +6,11 @@
 
 class JudgeCountTest {
     @Test
-    void toMessageNothing() {
-        JudgeCount count = new JudgeCount(0, 0);
-
-        assertThat(count.toMessage()).isEqualTo("낫싱");
-    }
-
-    @Test
-    void toMessageBallOnly() {
-        JudgeCount count = new JudgeCount(2, 0);
-
-        assertThat(count.toMessage()).isEqualTo("2볼");
-    }
-
-    @Test
-    void toMessageStrikeOnly() {
-        JudgeCount count = new JudgeCount(0, 1);
-
-        assertThat(count.toMessage()).isEqualTo("1스트라이크");
-    }
-
-    @Test
-    void toMessageBallAndStrike() {
+    void exposesBallAndStrike() {
         JudgeCount count = new JudgeCount(1, 2);
 
-        assertThat(count.toMessage()).isEqualTo("1볼 2스트라이크");
+        assertThat(count.ball()).isEqualTo(1);
+        assertThat(count.strike()).isEqualTo(2);
     }
 
     @Test
diff --git a/src/test/java/domain/NumbersJudgeTest.java b/src/test/java/domain/NumbersJudgeTest.java
index aebc92da..c031fa9c 100644
--- a/src/test/java/domain/NumbersJudgeTest.java
+++ b/src/test/java/domain/NumbersJudgeTest.java
@@ -11,7 +11,8 @@ void judgeAllStrikes() {
         Numbers guess = Numbers.from("123");
 
         assertThat(answer.judge(guess).isThreeStrikes()).isTrue();
-        assertThat(answer.judge(guess).toMessage()).isEqualTo("3스트라이크");
+        assertThat(answer.judge(guess).ball()).isEqualTo(0);
+        assertThat(answer.judge(guess).strike()).isEqualTo(3);
     }
 
     @Test
@@ -19,7 +20,8 @@ void judgeBallAndStrike() {
         Numbers answer = Numbers.from("123");
         Numbers guess = Numbers.from("132");
 
-        assertThat(answer.judge(guess).toMessage()).isEqualTo("2볼 1스트라이크");
+        assertThat(answer.judge(guess).ball()).isEqualTo(2);
+        assertThat(answer.judge(guess).strike()).isEqualTo(1);
     }
 
     @Test
@@ -27,6 +29,7 @@ void judgeNothing() {
         Numbers answer = Numbers.from("123");
         Numbers guess = Numbers.from("456");
 
-        assertThat(answer.judge(guess).toMessage()).isEqualTo("낫싱");
+        assertThat(answer.judge(guess).ball()).isEqualTo(0);
+        assertThat(answer.judge(guess).strike()).isEqualTo(0);
     }
 }

From ecd367a344580b3a9889d5265fbc827fc6bca8d3 Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Mon, 2 Feb 2026 21:13:31 +0900
Subject: [PATCH 27/29] =?UTF-8?q?refactor:=20restart=20=EA=B2=80=EC=A6=9D?=
 =?UTF-8?q?=20gamecontroller=EB=A1=9C=20=EC=9D=B4=EB=8F=99?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/main/java/controller/GameController.java | 10 ++++++++-
 src/main/java/util/Validator.java            |  2 +-
 src/main/java/view/InputView.java            | 23 +++-----------------
 3 files changed, 13 insertions(+), 22 deletions(-)

diff --git a/src/main/java/controller/GameController.java b/src/main/java/controller/GameController.java
index 48990b70..7acaa50a 100644
--- a/src/main/java/controller/GameController.java
+++ b/src/main/java/controller/GameController.java
@@ -2,6 +2,7 @@
 
 import domain.JudgeCount;
 import service.GameService;
+import util.Validator;
 import view.InputView;
 import view.OutputView;
 
@@ -44,6 +45,13 @@ private void playUntilWin() {
     }
 
     private boolean shouldStop() {
-        return inputView.readRestartCommand() == 2;
+        while (true) {
+            String input = inputView.readRestartCommand();
+            String error = Validator.restartError(input);
+            if (error == null) {
+                return "2".equals(input);
+            }
+            outputView.printError(error);
+        }
     }
 }
diff --git a/src/main/java/util/Validator.java b/src/main/java/util/Validator.java
index fc5b5911..0b3de9af 100644
--- a/src/main/java/util/Validator.java
+++ b/src/main/java/util/Validator.java
@@ -45,7 +45,7 @@ public static String restartError(String input) {
         if (RESTART_CODE.equals(input) || EXIT_CODE.equals(input)) {
             return null;
         }
-        return errorMessage(String.format("재시작은 %s, 종료는 %s만 입력 가능합니다.", RESTART_CODE, EXIT_CODE));
+        return errorMessage(String.format("%s(재시작), %s(종료)만 입력 가능합니다.", RESTART_CODE, EXIT_CODE));
     }
 
     private static String errorMessage(String message) {
diff --git a/src/main/java/view/InputView.java b/src/main/java/view/InputView.java
index 66fdf585..4e5ddbf7 100644
--- a/src/main/java/view/InputView.java
+++ b/src/main/java/view/InputView.java
@@ -1,10 +1,6 @@
 package view;
 
-import util.Validator;
-
 import java.util.Scanner;
-import java.util.function.Consumer;
-import java.util.function.Function;
 
 public class InputView {
     private static final String GUESS_PROMPT = "숫자를 입력해주세요 : ";
@@ -17,21 +13,8 @@ public String readGuess() {
         return scanner.nextLine().trim();
     }
 
-    public int readRestartCommand() {
-        String input = readUntilValid(System.out::println, Validator::restartError);
-        return Integer.parseInt(input);
-    }
-
-    private String readUntilValid(Consumer<String> printer, Function<String, String> validator) {
-        while (true) {
-            printer.accept(InputView.RESTART_PROMPT);
-            String input = scanner.nextLine().trim();
-            String error = validator.apply(input);
-
-            if (error == null) {
-                return input;
-            }
-            System.out.println(error);
-        }
+    public String readRestartCommand() {
+        System.out.println(RESTART_PROMPT);
+        return scanner.nextLine().trim();
     }
 }

From b18ee638c5faf195cbf2b3de73f60d26fd6326ae Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Mon, 2 Feb 2026 21:48:11 +0900
Subject: [PATCH 28/29] =?UTF-8?q?feat(game):=20=EC=8A=A4=ED=8A=B8=EB=9D=BC?=
 =?UTF-8?q?=EC=9D=B4=ED=81=AC=20=EB=B3=BC=20=EC=88=9C=EC=84=9C=20=EB=B0=94?=
 =?UTF-8?q?=EA=BE=B8=EA=B8=B0?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/main/java/view/OutputView.java | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/main/java/view/OutputView.java b/src/main/java/view/OutputView.java
index f595ede5..0b3a3cae 100644
--- a/src/main/java/view/OutputView.java
+++ b/src/main/java/view/OutputView.java
@@ -28,11 +28,11 @@ private String formatResult(JudgeCount count) {
         if (ball == 0 && strike == 0) return "낫싱";
 
         StringBuilder sb = new StringBuilder();
-        if (ball > 0) {
-            sb.append(ball).append("볼 ");
-        }
         if (strike > 0) {
-            sb.append(strike).append("스트라이크");
+            sb.append(strike).append("스트라이크 ");
+        }
+        if (ball > 0) {
+            sb.append(ball).append("볼");
         }
         return sb.toString().trim();
     }

From 98fbea3d538e06b4b6737983f0892bff79631151 Mon Sep 17 00:00:00 2001
From: "frank.jeong" <frank.jeong@frankjeongui-MacBookPro.local>
Date: Mon, 2 Feb 2026 22:11:12 +0900
Subject: [PATCH 29/29] =?UTF-8?q?refactor:=20java=20=EC=BB=A8=EB=B2=A4?=
 =?UTF-8?q?=EC=85=98=20=EB=B3=80=EC=88=98=20=EC=9D=B4=EB=A6=84=20=ED=95=9C?=
 =?UTF-8?q?=EA=B8=80=EC=9E=90=20=EC=A0=9C=EA=B1=B0?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/main/java/controller/GameController.java  |  4 ++--
 src/main/java/domain/Number.java              |  6 +++---
 src/main/java/domain/Numbers.java             | 20 +++++++++----------
 .../java/service/RandomNumberGenerator.java   | 16 +++++++--------
 src/main/java/util/Validator.java             | 12 +++++------
 5 files changed, 29 insertions(+), 29 deletions(-)

diff --git a/src/main/java/controller/GameController.java b/src/main/java/controller/GameController.java
index 7acaa50a..2ba53453 100644
--- a/src/main/java/controller/GameController.java
+++ b/src/main/java/controller/GameController.java
@@ -37,8 +37,8 @@ private void playUntilWin() {
             try {
                 JudgeCount count = gameService.play(inputView.readGuess());
                 outputView.printResult(count);
-            } catch (IllegalArgumentException e) {
-                outputView.printError(e.getMessage());
+            } catch (IllegalArgumentException exception) {
+                outputView.printError(exception.getMessage());
             }
         }
         outputView.printGameEndMessage();
diff --git a/src/main/java/domain/Number.java b/src/main/java/domain/Number.java
index b8c80a1b..1674b1f2 100644
--- a/src/main/java/domain/Number.java
+++ b/src/main/java/domain/Number.java
@@ -9,10 +9,10 @@ private Number(int value) {
         this.value = value;
     }
 
-    public static Number fromChar(char c) {
-        String error = Validator.numberError(c);
+    public static Number fromChar(char digitChar) {
+        String error = Validator.numberError(digitChar);
         if (error != null) throw new IllegalArgumentException(error);
-        return new Number(c - '0');
+        return new Number(digitChar - '0');
     }
 
     public int value() {
diff --git a/src/main/java/domain/Numbers.java b/src/main/java/domain/Numbers.java
index af05168e..35be4abf 100644
--- a/src/main/java/domain/Numbers.java
+++ b/src/main/java/domain/Numbers.java
@@ -22,11 +22,11 @@ public static Numbers from(String input) {
     }
 
     private static List<Number> parse(String input) {
-        List<Number> nums = new ArrayList<>(LENGTH);
-        for (char c : input.toCharArray()) {
-            nums.add(Number.fromChar(c));
+        List<Number> parsedNumbers = new ArrayList<>(LENGTH);
+        for (char digitChar : input.toCharArray()) {
+            parsedNumbers.add(Number.fromChar(digitChar));
         }
-        return nums;
+        return parsedNumbers;
     }
 
     public int get(int index) {
@@ -34,8 +34,8 @@ public int get(int index) {
     }
 
     public boolean contains(int number) {
-        for (Number n : numbers) {
-            if (n.same(number)) {
+        for (Number numberItem : numbers) {
+            if (numberItem.same(number)) {
                 return true;
             }
         }
@@ -49,13 +49,13 @@ public int size() {
     public JudgeCount judge(Numbers guess) {
         int ball = 0;
         int strike = 0;
-        for (int i = 0; i < size(); i++) {
-            int g = guess.get(i);
-            if (g == get(i)) {
+        for (int index = 0; index < size(); index++) {
+            int guessDigit = guess.get(index);
+            if (guessDigit == get(index)) {
                 strike++;
                 continue;
             }
-            if (contains(g)) {
+            if (contains(guessDigit)) {
                 ball++;
             }
         }
diff --git a/src/main/java/service/RandomNumberGenerator.java b/src/main/java/service/RandomNumberGenerator.java
index 0838d9f2..638b47b4 100644
--- a/src/main/java/service/RandomNumberGenerator.java
+++ b/src/main/java/service/RandomNumberGenerator.java
@@ -11,16 +11,16 @@ public Numbers numberGenerate() {
         return Numbers.from("" + numbers[0] + numbers[1] + numbers[2]);
     }
 
-    private void shuffle(int[] arr) {
-        for (int i = arr.length - 1; i > 0; i--) {
-            int j = ThreadLocalRandom.current().nextInt(i + 1);
-            swap(arr, i, j);
+    private void shuffle(int[] numbers) {
+        for (int currentIndex = numbers.length - 1; currentIndex > 0; currentIndex--) {
+            int swapIndex = ThreadLocalRandom.current().nextInt(currentIndex + 1);
+            swap(numbers, currentIndex, swapIndex);
         }
     }
 
-    private void swap(int[] arr, int i, int j) {
-        int tmp = arr[i];
-        arr[i] = arr[j];
-        arr[j] = tmp;
+    private void swap(int[] numbers, int firstIndex, int secondIndex) {
+        int temp = numbers[firstIndex];
+        numbers[firstIndex] = numbers[secondIndex];
+        numbers[secondIndex] = temp;
     }
 }
diff --git a/src/main/java/util/Validator.java b/src/main/java/util/Validator.java
index 0b3de9af..ea7314d9 100644
--- a/src/main/java/util/Validator.java
+++ b/src/main/java/util/Validator.java
@@ -19,23 +19,23 @@ public static String guessError(String input) {
     private static String validateCharacters(String input) {
         Set<Character> uniqueChars = new HashSet<>();
 
-        for (char c : input.toCharArray()) {
-            String error = numberError(c);
+        for (char digitChar : input.toCharArray()) {
+            String error = numberError(digitChar);
             if (error != null) {
                 return error;
             }
-            if (!uniqueChars.add(c)) {
+            if (!uniqueChars.add(digitChar)) {
                 return errorMessage("중복된 숫자는 사용할 수 없습니다.");
             }
         }
         return null;
     }
 
-    public static String numberError(char c) {
-        if (!Character.isDigit(c)) {
+    public static String numberError(char digitChar) {
+        if (!Character.isDigit(digitChar)) {
             return errorMessage("숫자만 입력해야 합니다.");
         }
-        if (c == '0') {
+        if (digitChar == '0') {
             return errorMessage("0은 사용할 수 없습니다.");
         }
         return null;