♻️ 코드 리팩토링 : 기술 정보 도메인 2차 리팩토링 및 Swagger 개선

build.gradle

@@ -40,9 +40,18 @@ dependencies {
     // Spring Actuator
     implementation 'org.springframework.boot:spring-boot-starter-actuator'
 
+    // Spring Cache
+    implementation 'org.springframework.boot:spring-boot-starter-cache'
+
+    // Spring Retry
+    implementation 'org.springframework.retry:spring-retry'
+
     // H2
     runtimeOnly 'com.h2database:h2'
 
+    // Caffeine
+    implementation 'com.github.ben-manes.caffeine:caffeine'
+
     // Redis
     implementation 'org.springframework.boot:spring-boot-starter-data-redis'
 

src/main/java/darkoverload/itzip/ItzipApplication.java

@@ -3,8 +3,10 @@
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.data.jpa.repository.config.EnableJpaAuditing;
+import org.springframework.retry.annotation.EnableRetry;
 import org.springframework.scheduling.annotation.EnableScheduling;
 
+@EnableRetry
 @EnableScheduling
 @EnableJpaAuditing
 @SpringBootApplication

src/main/java/darkoverload/itzip/feature/jwt/infrastructure/CustomUserDetails.java

@@ -42,6 +42,10 @@ public String getUsername() {
         return email;
     }
 
+    public String getUserNickname() {
+        return nickname;
+    }
+
     @Override
     public boolean isAccountNonExpired() {
         return true;

src/main/java/darkoverload/itzip/feature/techinfo/application/event/handler/BlogEventHandler.java

@@ -0,0 +1,31 @@
+package darkoverload.itzip.feature.techinfo.application.event.handler;
+
+import darkoverload.itzip.feature.techinfo.application.event.payload.UserCreatedEvent;
+import darkoverload.itzip.feature.techinfo.application.service.command.BlogCommandService;
+import org.springframework.stereotype.Component;
+import org.springframework.transaction.event.TransactionPhase;
+import org.springframework.transaction.event.TransactionalEventListener;
+
+/**
+ * 회원 생성 이벤트를 처리하여 블로그 생성을 수행하는 이벤트 핸들러입니다.
+ *
+ * <p>
+ *     트랜잭션이 커밋된 후에 실행되며,
+ *     {@link UserCreatedEvent} 발생 시 {@link BlogCommandService#create(Long)} 를 호출합니다.
+ * </p>
+ */
+@Component
+public class BlogEventHandler {
+
+    private final BlogCommandService blogCommandService;
+
+    public BlogEventHandler(final BlogCommandService blogCommandService) {
+        this.blogCommandService = blogCommandService;
+    }
+
+    @TransactionalEventListener(phase = TransactionPhase.AFTER_COMMIT)
+    public void handleUserCreated(final UserCreatedEvent event) {
+        blogCommandService.create(event.userId());
+    }
+
+}

src/main/java/darkoverload/itzip/feature/techinfo/application/event/handler/CommentEventHandler.java

@@ -0,0 +1,26 @@
+package darkoverload.itzip.feature.techinfo.application.event.handler;
+
+import darkoverload.itzip.feature.techinfo.application.event.payload.ArticleHiddenEvent;
+import darkoverload.itzip.feature.techinfo.application.service.command.CommentCommandService;
+import org.springframework.context.event.EventListener;
+import org.springframework.stereotype.Component;
+
+/**
+ * 아티클 삭제(숨김) 이벤트를 처리하여 해당 아티클의 댓글을 삭제(숨김) 수행하는 핸들러입니다.
+ */
+@Component
+public class CommentEventHandler {
+
+    private final CommentCommandService commandService;
+
+    public CommentEventHandler(final CommentCommandService commandService) {
+        this.commandService = commandService;
+    }
+
+    @EventListener
+    public void handleArticleHidden(final ArticleHiddenEvent event) {
+        final String articleIdHex = event.articleId().toHexString();
+        commandService.deleteByArticleId(articleIdHex);
+    }
+
+}

src/main/java/darkoverload/itzip/feature/techinfo/application/event/handler/LikeEventHandler.java

@@ -0,0 +1,33 @@
+package darkoverload.itzip.feature.techinfo.application.event.handler;
+
+import darkoverload.itzip.feature.techinfo.application.event.payload.LikeCancelledEvent;
+import darkoverload.itzip.feature.techinfo.application.event.payload.LikedEvent;
+import darkoverload.itzip.feature.techinfo.application.service.cache.LikeCacheService;
+import org.springframework.stereotype.Component;
+import org.springframework.transaction.event.TransactionPhase;
+import org.springframework.transaction.event.TransactionalEventListener;
+
+/**
+ * 좋아요 및 취소 이벤트를 수행하는 핸들러입니다.
+ * 트랜잭션 커밋 이후에 실행됩니다.
+ */
+@Component
+public class LikeEventHandler {
+
+    private final LikeCacheService cacheService;
+
+    public LikeEventHandler(final LikeCacheService likeCacheService) {
+        this.cacheService = likeCacheService;
+    }
+
+    @TransactionalEventListener(phase = TransactionPhase.AFTER_COMMIT)
+    public void handleArticleLikedEvent(final LikedEvent event) {
+        cacheService.merge(event.articleId());
+    }
+
+    @TransactionalEventListener(phase = TransactionPhase.AFTER_COMMIT)
+    public void handleArticleLikeCancelledEvent(final LikeCancelledEvent event) {
+        cacheService.subtract(event.articleId());
+    }
+
+}

src/main/java/darkoverload/itzip/feature/techinfo/application/event/handler/ViewEventHandler.java

@@ -0,0 +1,25 @@
+package darkoverload.itzip.feature.techinfo.application.event.handler;
+
+import darkoverload.itzip.feature.techinfo.application.event.payload.ViewedEvent;
+import darkoverload.itzip.feature.techinfo.application.service.cache.ViewCacheService;
+import org.springframework.context.event.EventListener;
+import org.springframework.stereotype.Component;
+
+/**
+ * 조회 이벤트를 수행하는 핸들러입니다.
+ */
+@Component
+public class ViewEventHandler {
+
+    private final ViewCacheService cacheService;
+
+    public ViewEventHandler(final ViewCacheService cacheService) {
+        this.cacheService = cacheService;
+    }
+
+    @EventListener
+    public void handleArticleViewedEvent(final ViewedEvent event) {
+        cacheService.merge(event.articleId());
+    }
+
+}

src/main/java/darkoverload/itzip/feature/techinfo/application/event/payload/ArticleHiddenEvent.java

@@ -0,0 +1,11 @@
+package darkoverload.itzip.feature.techinfo.application.event.payload;
+
+import org.bson.types.ObjectId;
+
+/**
+ * 아티클 숨김 이벤트를 나타내는 레코드입니다.
+ *
+ * <p>아티클이 숨김 처리될 때 발생하며, 숨김 대상 아티클의 식별자를 포함합니다.</p>
+ */
+public record ArticleHiddenEvent(ObjectId articleId) {
+}

src/main/java/darkoverload/itzip/feature/techinfo/application/event/payload/LikeCancelledEvent.java

@@ -0,0 +1,9 @@
+package darkoverload.itzip.feature.techinfo.application.event.payload;
+
+/**
+ * 좋아요 취소 이벤트를 나타내는 레코드입니다.
+ *
+ * <p>아티클의 좋아요가 취소될 때 발생하며, 해당 아티클의 식별자를 포함합니다.</p>
+ */
+public record LikeCancelledEvent(String articleId) {
+}

src/main/java/darkoverload/itzip/feature/techinfo/application/event/payload/LikedEvent.java

@@ -0,0 +1,9 @@
+package darkoverload.itzip.feature.techinfo.application.event.payload;
+
+/**
+ * 좋아요 이벤트를 나타내는 레코드입니다.
+ *
+ * <p>아티클에 좋아요가 발생했을 때 발생하며, 해당 게시글의 식별자를 포함합니다.</p>
+ */
+public record LikedEvent(String articleId) {
+}

src/main/java/darkoverload/itzip/feature/techinfo/application/event/payload/UserCreatedEvent.java

@@ -0,0 +1,9 @@
+package darkoverload.itzip.feature.techinfo.application.event.payload;
+
+/**
+ * 사용자 생성 이벤트를 나타내는 레코드입니다.
+ *
+ * <p>사용자가 생성되었을 때 발생하며, 생성된 사용자의 식별자를 포함합니다.</p>
+ */
+public record UserCreatedEvent(Long userId) {
+}

src/main/java/darkoverload/itzip/feature/techinfo/application/event/payload/ViewedEvent.java

@@ -0,0 +1,11 @@
+package darkoverload.itzip.feature.techinfo.application.event.payload;
+
+import org.bson.types.ObjectId;
+
+/**
+ * 조회 이벤트를 나타내는 레코드입니다.
+ *
+ * <p>아티클이 조회될 때 발생하며, 조회된 게시글의 식별자를 포함합니다.</p>
+ */
+public record ViewedEvent(ObjectId articleId) {
+}

src/main/java/darkoverload/itzip/feature/techinfo/application/generator/PageableGenerator.java

@@ -0,0 +1,29 @@
+package darkoverload.itzip.feature.techinfo.application.generator;
+
+import darkoverload.itzip.feature.techinfo.application.type.SortType;
+import org.springframework.data.domain.PageRequest;
+import org.springframework.data.domain.Pageable;
+import org.springframework.data.domain.Sort;
+
+/**
+ * 페이지와 정렬 옵션에 따른 Pageable 객체를 생성하는 유틸리티 클래스입니다.
+ */
+public class PageableGenerator {
+
+    private static final String FIELD_VIEW_COUNT = "viewCount";
+    private static final String FIELD_LIKE_COUNT = "likesCount";
+    private static final String FIELD_CREATED_AT = "createdAt";
+
+    private PageableGenerator() {
+    }
+
+    public static Pageable generate(final int page, final int size, final SortType type) {
+        return switch (type) {
+            case VIEW_COUNT-> PageRequest.of(page, size, Sort.by(Sort.Direction.DESC, FIELD_VIEW_COUNT));
+            case LIKE_COUNT -> PageRequest.of(page, size, Sort.by(Sort.Direction.DESC, FIELD_LIKE_COUNT));
+            case OLDEST -> PageRequest.of(page, size, Sort.by(Sort.Direction.ASC, FIELD_CREATED_AT));
+            default -> PageRequest.of(page, size, Sort.by(Sort.Direction.DESC, FIELD_CREATED_AT));
+        };
+    }
+
+}

src/main/java/darkoverload/itzip/feature/techinfo/application/generator/PagedModelGenerator.java

@@ -0,0 +1,31 @@
+package darkoverload.itzip.feature.techinfo.application.generator;
+
+import org.springframework.data.domain.Page;
+import org.springframework.hateoas.EntityModel;
+import org.springframework.hateoas.PagedModel;
+import org.springframework.hateoas.PagedModel.PageMetadata;
+
+/**
+ * Spring Data의 Page 객체를 HATEOAS의 PagedModel로 변환하는 유틸리티 클래스입니다.
+ */
+public class PagedModelGenerator {
+
+    private PagedModelGenerator() {
+    }
+
+    public static <T> PagedModel<EntityModel<T>> generate(final Page<T> page) {
+        final PageMetadata metadata = new PageMetadata(
+                page.getNumber(),
+                page.getSize(),
+                page.getTotalElements(),
+                page.getTotalPages());
+
+        return PagedModel.of(
+                page.stream()
+                        .map(EntityModel::of)
+                        .toList(),
+                metadata
+        );
+    }
+
+}

src/main/java/darkoverload/itzip/feature/techinfo/application/generator/UpperCaseGenerator.java

@@ -0,0 +1,20 @@
+package darkoverload.itzip.feature.techinfo.application.generator;
+
+import java.util.Objects;
+
+/**
+ * 문자열을 대문자로 변환하는 유틸리티 클래스입니다.
+ */
+public class UpperCaseGenerator {
+
+    private UpperCaseGenerator() {
+    }
+
+    public static String generate(final String value) {
+        if (Objects.isNull(value) || value.isBlank()) {
+            throw new IllegalArgumentException("NULL 혹은 공백인 값을 변환할 수 없습니다.");
+        }
+        return value.toUpperCase();
+    }
+
+}

src/main/java/darkoverload/itzip/feature/techinfo/application/service/cache/LikeCacheService.java

@@ -0,0 +1,11 @@
+package darkoverload.itzip.feature.techinfo.application.service.cache;
+
+public interface LikeCacheService {
+
+    void merge(String articleId);
+
+    void subtract(String articleId);
+
+    void flush();
+
+}

src/main/java/darkoverload/itzip/feature/techinfo/application/service/cache/ViewCacheService.java

@@ -0,0 +1,11 @@
+package darkoverload.itzip.feature.techinfo.application.service.cache;
+
+import org.bson.types.ObjectId;
+
+public interface ViewCacheService {
+
+    void merge(ObjectId articleId);
+
+    void flush();
+
+}

src/main/java/darkoverload/itzip/feature/techinfo/application/service/cache/impl/LikeCacheServiceImpl.java

@@ -0,0 +1,78 @@
+package darkoverload.itzip.feature.techinfo.application.service.cache.impl;
+
+import darkoverload.itzip.feature.techinfo.application.service.cache.LikeCacheService;
+import darkoverload.itzip.feature.techinfo.application.service.command.ArticleCommandService;
+import darkoverload.itzip.feature.techinfo.infrastructure.persistence.cache.LikeCacheRepository;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.retry.annotation.Backoff;
+import org.springframework.retry.annotation.Recover;
+import org.springframework.retry.annotation.Retryable;
+import org.springframework.scheduling.annotation.Async;
+import org.springframework.scheduling.annotation.Scheduled;
+import org.springframework.stereotype.Service;
+
+import java.util.Map;
+
+/**
+ * 좋아요 캐시 처리를 위한 서비스 구현체입니다.
+ *
+ * <p>
+ *     좋아요 병합, 감소, 그리고 캐시 플러시 작업을 수행합니다.
+ *     재시도 로직과 비동기 처리(@Async)를 적용하여 일시적인 오류에 대비합니다.
+ * </p>
+ */
+@Slf4j
+@Service
+@RequiredArgsConstructor
+public class LikeCacheServiceImpl implements LikeCacheService {
+
+    private static final String FLUSH_DELAY = "30000";
+
+    private final LikeCacheRepository cacheRepository;
+
+    private final ArticleCommandService articleCommandService;
+
+    @Async
+    @Retryable(
+            value = Exception.class,
+            maxAttempts = 3,
+            backoff = @Backoff(delay = 1000)
+    )
+    @Override
+    public void merge(final String articleId) {
+        cacheRepository.merge(articleId, 1L);
+    }
+
+    @Recover
+    public void recoverMerge(final Exception e, final String articleId) {
+        log.error("좋아요 병합 재시도 실패: {}", articleId);
+    }
+
+    @Async
+    @Retryable(
+            value = Exception.class,
+            maxAttempts = 3,
+            backoff = @Backoff(delay = 1000)
+    )
+    @Override
+    public void subtract(final String articleId) {
+        cacheRepository.merge(articleId, -1L);
+    }
+
+    @Recover
+    public void recoverSubtract(final Exception e, final String articleId) {
+        log.error("좋아요 감소 재시도 실패: {}", articleId);
+    }
+
+    @Scheduled(fixedDelayString = FLUSH_DELAY)
+    public void flush() {
+        final Map<String, Long> batch = cacheRepository.retrieveAll();
+        if (batch.isEmpty()) {
+            return;
+        }
+        cacheRepository.clear();
+        batch.forEach(articleCommandService::updateLikesCount);
+    }
+
+}