Feat: 닉네임 변경 API 추가

src/main/java/com/join/core/avatar/controller/AvatarController.java

@@ -0,0 +1,31 @@
+package com.join.core.avatar.controller;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.join.core.avatar.domain.AvatarCommand;
+import com.join.core.avatar.domain.AvatarInfo;
+import com.join.core.avatar.domain.AvatarService;
+import com.join.core.common.response.ApiResponse;
+
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.tags.Tag;
+import lombok.RequiredArgsConstructor;
+
+@RequiredArgsConstructor
+@RestController
+@RequestMapping("${api.prefix}/avatars")
+public class AvatarController {
+
+	private final AvatarService avatarService;
+
+	@Tag(name = "${swagger.tag.sign-up}")
+	@Operation(summary = "닉네임 유효성 검사 API",
+		description = "닉네임 유효성 검사 API")
+	@GetMapping("/nickname/valid")
+	public ApiResponse<AvatarInfo.ValidNickname> isValidNickname(AvatarCommand.ChangeNickname command) {
+		return ApiResponse.ok(avatarService.isValid(command));
+	}
+
+}

src/main/java/com/join/core/avatar/domain/AvatarCommand.java

@@ -0,0 +1,17 @@
+package com.join.core.avatar.domain;
+
+import lombok.Builder;
+import lombok.Getter;
+
+public class AvatarCommand {
+
+	private AvatarCommand() {
+	}
+
+	@Builder
+	@Getter
+	public static class ChangeNickname {
+		private final String nickname;
+	}
+
+}

src/main/java/com/join/core/avatar/domain/AvatarInfo.java

@@ -0,0 +1,22 @@
+package com.join.core.avatar.domain;
+
+import lombok.Builder;
+import lombok.Getter;
+
+public class AvatarInfo {
+
+	private AvatarInfo() {
+	}
+
+	@Builder
+	@Getter
+	public static class ValidNickname {
+		private final boolean isValid;
+		private final String message;
+
+		public static ValidNickname valid() {
+			return new ValidNickname(true, "사용 가능한 닉네임이에요.");
+		}
+	}
+
+}

src/main/java/com/join/core/avatar/domain/AvatarReader.java

@@ -1,6 +1,8 @@
 package com.join.core.avatar.domain;
 
 public interface AvatarReader {
-    Avatar getAvatarByToken(String avatarToken);
+	Avatar getAvatarByToken(String avatarToken);
+
+	boolean existsByNickname(String nickname);
 
 }

src/main/java/com/join/core/avatar/domain/AvatarService.java

@@ -0,0 +1,7 @@
+package com.join.core.avatar.domain;
+
+public interface AvatarService {
+
+	AvatarInfo.ValidNickname isValid(AvatarCommand.ChangeNickname command);
+
+}

src/main/java/com/join/core/avatar/domain/AvatarServiceImpl.java

@@ -0,0 +1,29 @@
+package com.join.core.avatar.domain;
+
+import java.util.List;
+
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import lombok.RequiredArgsConstructor;
+
+@RequiredArgsConstructor
+@Transactional(readOnly = true)
+@Service
+public class AvatarServiceImpl implements AvatarService {
+
+	private final List<NicknameValidator> nicknameValidatorList;
+
+	@Override
+	public AvatarInfo.ValidNickname isValid(AvatarCommand.ChangeNickname command) {
+
+		for (NicknameValidator validator : nicknameValidatorList) {
+			AvatarInfo.ValidNickname validationResult = validator.validate(command);
+			if (!validationResult.isValid())
+				return validationResult;
+		}
+
+		return AvatarInfo.ValidNickname.valid();
+	}
+
+}

src/main/java/com/join/core/avatar/domain/NicknameDuplicationValidator.java

@@ -0,0 +1,23 @@
+package com.join.core.avatar.domain;
+
+import org.springframework.core.annotation.Order;
+import org.springframework.stereotype.Component;
+
+import lombok.RequiredArgsConstructor;
+
+@RequiredArgsConstructor
+@Order(2)
+@Component
+public class NicknameDuplicationValidator implements NicknameValidator {
+
+	private final AvatarReader avatarReader;
+
+	@Override
+	public AvatarInfo.ValidNickname validate(AvatarCommand.ChangeNickname command) {
+		if (avatarReader.existsByNickname(command.getNickname()))
+			return new AvatarInfo.ValidNickname(false, "이미 사용 중인 닉네임이에요.");
+
+		return AvatarInfo.ValidNickname.valid();
+	}
+
+}

src/main/java/com/join/core/avatar/domain/NicknameFormatValidator.java

@@ -0,0 +1,24 @@
+package com.join.core.avatar.domain;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.springframework.core.annotation.Order;
+import org.springframework.stereotype.Component;
+
+@Order(1)
+@Component
+public class NicknameFormatValidator implements NicknameValidator {
+
+	private static final Pattern pattern = Pattern.compile("^[가-힣a-zA-Z0-9]{2,7}$");
+
+	@Override
+	public AvatarInfo.ValidNickname validate(AvatarCommand.ChangeNickname command) {
+		Matcher matcher = pattern.matcher(command.getNickname());
+		if (!matcher.matches())
+			return new AvatarInfo.ValidNickname(false, "2-7자리 한글/영문/숫자로 입력해주세요.");
+
+		return AvatarInfo.ValidNickname.valid();
+	}
+
+}

src/main/java/com/join/core/avatar/domain/NicknameValidator.java

@@ -0,0 +1,7 @@
+package com.join.core.avatar.domain;
+
+public interface NicknameValidator {
+
+	AvatarInfo.ValidNickname validate(AvatarCommand.ChangeNickname command);
+
+}

src/main/java/com/join/core/avatar/repository/AvatarReaderImpl.java

@@ -21,4 +21,10 @@ public Avatar getAvatarByToken(String avatarToken) {
                 .orElseThrow(() -> new EntityNotFoundException(ErrorCode.AVATAR_NOT_FOUND));
     }
 
+    @Transactional(readOnly = true)
+    @Override
+    public boolean existsByNickname(String nickname) {
+        return avatarRepository.existsByNickname(nickname);
+    }
+
 }

src/main/java/com/join/core/avatar/repository/AvatarRepository.java

@@ -1,11 +1,17 @@
 package com.join.core.avatar.repository;
 
-import com.join.core.avatar.domain.Avatar;
+import java.util.Optional;
+
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.query.Param;
 
-import java.util.Optional;
+import com.join.core.avatar.domain.Avatar;
 
 public interface AvatarRepository extends JpaRepository<Avatar, Long> {
-    Optional<Avatar> findByAvatarToken(String avatarToken);
+	Optional<Avatar> findByAvatarToken(String avatarToken);
+
+	@Query("select (count(a) > 0) from Avatar a where a.nickname = :nickname")
+	boolean existsByNickname(@Param("nickname") String nickname);
 
 }