[Feature/BE] 예외 상황시 예외 코드를 반환

backend/src/docs/asciidoc/products.adoc

@@ -23,3 +23,7 @@ operation::products-get[snippets='http-request,http-response']
 - 없을 경우 등록 순서
 
 operation::products-page-get[snippets='http-request,http-response']
+
+=== 특정 제품의 사용자 통계를 조회
+
+operation::products-member-statistics-get[snippets='http-request,http-response']

backend/src/main/java/com/woowacourse/f12/application/inventoryproduct/InventoryProductService.java

@@ -6,7 +6,7 @@
 import com.woowacourse.f12.dto.request.inventoryproduct.ProfileProductRequest;
 import com.woowacourse.f12.dto.response.inventoryproduct.InventoryProductsResponse;
 import com.woowacourse.f12.exception.badrequest.InvalidProfileProductException;
-import com.woowacourse.f12.exception.notfound.InventoryItemNotFoundException;
+import com.woowacourse.f12.exception.notfound.InventoryProductNotFoundException;
 import com.woowacourse.f12.exception.notfound.MemberNotFoundException;
 import java.util.List;
 import java.util.Objects;
@@ -51,7 +51,7 @@ private void updateProfileProduct(final ProfileProductRequest profileProductRequ
 
     private void updateProfileProduct(final Long inventoryItemId, final boolean selected) {
         final InventoryProduct inventoryProduct = inventoryProductRepository.findById(inventoryItemId)
-                .orElseThrow(InventoryItemNotFoundException::new);
+                .orElseThrow(InventoryProductNotFoundException::new);
         inventoryProduct.updateSelected(selected);
     }
 

backend/src/main/java/com/woowacourse/f12/application/member/MemberService.java

@@ -5,14 +5,14 @@
 import com.woowacourse.f12.domain.member.JobType;
 import com.woowacourse.f12.domain.member.Member;
 import com.woowacourse.f12.domain.member.MemberRepository;
-import com.woowacourse.f12.dto.CareerLevelConstant;
-import com.woowacourse.f12.dto.JobTypeConstant;
 import com.woowacourse.f12.dto.request.member.MemberRequest;
 import com.woowacourse.f12.dto.request.member.MemberSearchRequest;
 import com.woowacourse.f12.dto.response.member.MemberPageResponse;
 import com.woowacourse.f12.dto.response.member.MemberResponse;
 import com.woowacourse.f12.exception.badrequest.InvalidProfileArgumentException;
 import com.woowacourse.f12.exception.notfound.MemberNotFoundException;
+import com.woowacourse.f12.presentation.member.CareerLevelConstant;
+import com.woowacourse.f12.presentation.member.JobTypeConstant;
 import java.util.Objects;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Slice;

backend/src/main/java/com/woowacourse/f12/application/product/ProductService.java

@@ -1,12 +1,21 @@
 package com.woowacourse.f12.application.product;
 
+import com.woowacourse.f12.domain.member.CareerLevel;
+import com.woowacourse.f12.domain.member.JobType;
 import com.woowacourse.f12.domain.product.Category;
 import com.woowacourse.f12.domain.product.Product;
 import com.woowacourse.f12.domain.product.ProductRepository;
+import com.woowacourse.f12.domain.review.CareerLevelCount;
+import com.woowacourse.f12.domain.review.JobTypeCount;
+import com.woowacourse.f12.domain.review.MemberInfoStatistics;
+import com.woowacourse.f12.domain.review.ReviewRepository;
 import com.woowacourse.f12.dto.response.product.ProductPageResponse;
 import com.woowacourse.f12.dto.response.product.ProductResponse;
-import com.woowacourse.f12.exception.notfound.KeyboardNotFoundException;
+import com.woowacourse.f12.dto.response.product.ProductStatisticsResponse;
+import com.woowacourse.f12.exception.notfound.ProductNotFoundException;
 import com.woowacourse.f12.presentation.product.CategoryConstant;
+import java.util.List;
+import java.util.Map;
 import java.util.Objects;
 import org.springframework.data.domain.Pageable;
 import org.springframework.stereotype.Service;
@@ -17,14 +26,16 @@
 public class ProductService {
 
     private final ProductRepository productRepository;
+    private final ReviewRepository reviewRepository;
 
-    public ProductService(final ProductRepository productRepository) {
+    public ProductService(final ProductRepository productRepository, final ReviewRepository reviewRepository) {
         this.productRepository = productRepository;
+        this.reviewRepository = reviewRepository;
     }
 
     public ProductResponse findById(final Long id) {
         final Product product = productRepository.findById(id)
-                .orElseThrow(KeyboardNotFoundException::new);
+                .orElseThrow(ProductNotFoundException::new);
         return ProductResponse.from(product);
     }
 
@@ -36,4 +47,26 @@ public ProductPageResponse findPage(final CategoryConstant categoryConstant, fin
         final Category category = categoryConstant.toCategory();
         return ProductPageResponse.from(productRepository.findPageByCategory(category, pageable));
     }
+
+    public ProductStatisticsResponse calculateMemberStatisticsById(final Long productId) {
+        if (!productRepository.existsById(productId)) {
+            throw new ProductNotFoundException();
+        }
+        final Map<CareerLevel, Double> careerLevel = calculateWithCareerLevel(productId);
+        final Map<JobType, Double> jobType = calculateWithJobType(productId);
+        return ProductStatisticsResponse.of(careerLevel, jobType);
+    }
+
+    private Map<CareerLevel, Double> calculateWithCareerLevel(final Long productId) {
+        final List<CareerLevelCount> careerLevelCounts = reviewRepository.findCareerLevelCountByProductId(productId);
+        final MemberInfoStatistics<CareerLevelCount, CareerLevel> careerLevelStatistics = new MemberInfoStatistics<>(
+                careerLevelCounts);
+        return careerLevelStatistics.calculateStatistics(CareerLevel.values());
+    }
+
+    private Map<JobType, Double> calculateWithJobType(final Long productId) {
+        final List<JobTypeCount> jobTypeCounts = reviewRepository.findJobTypeCountByProductId(productId);
+        final MemberInfoStatistics<JobTypeCount, JobType> jobTypeStatistics = new MemberInfoStatistics<>(jobTypeCounts);
+        return jobTypeStatistics.calculateStatistics(JobType.values());
+    }
 }

backend/src/main/java/com/woowacourse/f12/application/review/ReviewService.java

@@ -13,8 +13,8 @@
 import com.woowacourse.f12.dto.response.review.ReviewWithProductPageResponse;
 import com.woowacourse.f12.exception.badrequest.AlreadyWrittenReviewException;
 import com.woowacourse.f12.exception.forbidden.NotAuthorException;
-import com.woowacourse.f12.exception.notfound.KeyboardNotFoundException;
 import com.woowacourse.f12.exception.notfound.MemberNotFoundException;
+import com.woowacourse.f12.exception.notfound.ProductNotFoundException;
 import com.woowacourse.f12.exception.notfound.ReviewNotFoundException;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Slice;
@@ -45,7 +45,7 @@ public Long saveReviewAndInventoryProduct(final Long productId, final Long membe
         final Member member = memberRepository.findById(memberId)
                 .orElseThrow(MemberNotFoundException::new);
         final Product product = productRepository.findById(productId)
-                .orElseThrow(KeyboardNotFoundException::new);
+                .orElseThrow(ProductNotFoundException::new);
         final Long reviewId = saveReview(reviewRequest, member, product);
         saveInventoryProduct(member, product);
         return reviewId;
@@ -83,7 +83,7 @@ public ReviewPageResponse findPageByProductId(final Long productId, final Pageab
 
     private void validateKeyboardExists(final Long productId) {
         if (!productRepository.existsById(productId)) {
-            throw new KeyboardNotFoundException();
+            throw new ProductNotFoundException();
         }
     }
 

backend/src/main/java/com/woowacourse/f12/domain/member/CareerLevel.java

@@ -1,6 +1,6 @@
 package com.woowacourse.f12.domain.member;
 
-public enum CareerLevel {
+public enum CareerLevel implements MemberInfo {
 
     NONE,
     JUNIOR,

backend/src/main/java/com/woowacourse/f12/domain/member/JobType.java

@@ -3,11 +3,10 @@
 import lombok.Getter;
 
 @Getter
-public enum JobType {
+public enum JobType implements MemberInfo {
 
     FRONTEND,
     BACKEND,
     MOBILE,
-    ETC
-    ;
+    ETC;
 }

backend/src/main/java/com/woowacourse/f12/domain/member/MemberInfo.java

@@ -0,0 +1,5 @@
+package com.woowacourse.f12.domain.member;
+
+public interface MemberInfo {
+
+}

backend/src/main/java/com/woowacourse/f12/domain/member/MemberRepositoryCustomImpl.java

@@ -1,5 +1,7 @@
 package com.woowacourse.f12.domain.member;
 
+import static com.woowacourse.f12.domain.member.QMember.member;
+
 import com.querydsl.core.types.dsl.BooleanExpression;
 import com.querydsl.jpa.impl.JPAQuery;
 import com.querydsl.jpa.impl.JPAQueryFactory;
@@ -12,7 +14,6 @@
 
 public class MemberRepositoryCustomImpl extends QuerydslRepositorySupport implements MemberRepositoryCustom {
 
-    private final QMember member = QMember.member;
     private final JPAQueryFactory jpaQueryFactory;
 
     public MemberRepositoryCustomImpl(final JPAQueryFactory jpaQueryFactory) {
@@ -23,8 +24,7 @@ public MemberRepositoryCustomImpl(final JPAQueryFactory jpaQueryFactory) {
     public Slice<Member> findBySearchConditions(final String keyword, final CareerLevel careerLevel,
                                                 final JobType jobType,
                                                 final Pageable pageable) {
-        final JPAQuery<Member> jpaQuery = jpaQueryFactory.select(member)
-                .from(member)
+        final JPAQuery<Member> jpaQuery = jpaQueryFactory.selectFrom(member)
                 .where(
                         containsKeyword(keyword),
                         eqCareerLevel(careerLevel),
@@ -37,7 +37,7 @@ public Slice<Member> findBySearchConditions(final String keyword, final CareerLe
     }
 
     private BooleanExpression containsKeyword(final String keyword) {
-        if (keyword == null || keyword.isBlank()) {
+        if (Objects.isNull(keyword) || keyword.isBlank()) {
             return null;
         }
         return member.gitHubId.contains(keyword);
@@ -57,7 +57,7 @@ public BooleanExpression eqJobType(final JobType jobType) {
         return member.jobType.eq(jobType);
     }
 
-    private SliceImpl<Member> toSlice(final Pageable pageable, final List<Member> members) {
+    private Slice<Member> toSlice(final Pageable pageable, final List<Member> members) {
         if (members.size() > pageable.getPageSize()) {
             members.remove(members.size() - 1);
             return new SliceImpl<>(members, pageable, true);

backend/src/main/java/com/woowacourse/f12/domain/review/CareerLevelCount.java

@@ -0,0 +1,27 @@
+package com.woowacourse.f12.domain.review;
+
+import com.querydsl.core.annotations.QueryProjection;
+import com.woowacourse.f12.domain.member.CareerLevel;
+import com.woowacourse.f12.domain.member.MemberInfo;
+
+public class CareerLevelCount implements Countable {
+
+    private final CareerLevel careerLevel;
+    private final long count;
+
+    @QueryProjection
+    public CareerLevelCount(final CareerLevel careerLevel, final long count) {
+        this.careerLevel = careerLevel;
+        this.count = count;
+    }
+
+    @Override
+    public MemberInfo getValue() {
+        return careerLevel;
+    }
+
+    @Override
+    public long getCount() {
+        return count;
+    }
+}

backend/src/main/java/com/woowacourse/f12/domain/review/Countable.java

@@ -0,0 +1,10 @@
+package com.woowacourse.f12.domain.review;
+
+import com.woowacourse.f12.domain.member.MemberInfo;
+
+public interface Countable {
+
+    MemberInfo getValue();
+
+    long getCount();
+}

backend/src/main/java/com/woowacourse/f12/domain/review/JobTypeCount.java

@@ -0,0 +1,27 @@
+package com.woowacourse.f12.domain.review;
+
+import com.querydsl.core.annotations.QueryProjection;
+import com.woowacourse.f12.domain.member.JobType;
+import com.woowacourse.f12.domain.member.MemberInfo;
+
+public class JobTypeCount implements Countable {
+
+    private final JobType jobType;
+    private final long count;
+
+    @QueryProjection
+    public JobTypeCount(final JobType jobType, final long count) {
+        this.jobType = jobType;
+        this.count = count;
+    }
+
+    @Override
+    public MemberInfo getValue() {
+        return jobType;
+    }
+
+    @Override
+    public long getCount() {
+        return count;
+    }
+}

backend/src/main/java/com/woowacourse/f12/domain/review/MemberInfoStatistics.java

@@ -0,0 +1,46 @@
+package com.woowacourse.f12.domain.review;
+
+import com.woowacourse.f12.domain.member.MemberInfo;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+public class MemberInfoStatistics<E extends Countable, T extends MemberInfo> {
+
+    private static final int DECIMAL_PLACE = 2;
+    private static final double DEFAULT_VALUE = 0.00;
+    private static final double DECIMAL = 10.0;
+    private final List<E> elements;
+
+    public MemberInfoStatistics(final List<E> elements) {
+        this.elements = elements;
+    }
+
+    public Map<T, Double> calculateStatistics(final T[] values) {
+        final long totalCount = calculateTotalCount();
+        return Arrays.stream(values)
+                .collect(Collectors.toMap(Function.identity(),
+                        memberInfo -> calculateProportion(memberInfo, totalCount)));
+    }
+
+    private long calculateTotalCount() {
+        return elements.stream()
+                .mapToLong(Countable::getCount)
+                .sum();
+    }
+
+    private Double calculateProportion(final T t, final long totalCount) {
+        return elements.stream()
+                .filter(it -> it.getValue().equals(t))
+                .findAny()
+                .map(countable -> round(countable.getCount() / (double) totalCount))
+                .orElse(DEFAULT_VALUE);
+    }
+
+    private double round(double number) {
+        final double operand = Math.pow(DECIMAL, DECIMAL_PLACE);
+        return Math.round(number * operand) / operand;
+    }
+}

backend/src/main/java/com/woowacourse/f12/domain/review/ReviewRepository.java

@@ -7,7 +7,7 @@
 import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.data.jpa.repository.Query;
 
-public interface ReviewRepository extends JpaRepository<Review, Long> {
+public interface ReviewRepository extends JpaRepository<Review, Long>, ReviewRepositoryCustom {
 
     @Query("select r from Review r where r.product.id = :productId")
     Slice<Review> findPageByProductId(Long productId, Pageable pageable);

backend/src/main/java/com/woowacourse/f12/domain/review/ReviewRepositoryCustom.java

@@ -0,0 +1,10 @@
+package com.woowacourse.f12.domain.review;
+
+import java.util.List;
+
+public interface ReviewRepositoryCustom {
+
+    List<CareerLevelCount> findCareerLevelCountByProductId(Long productId);
+
+    List<JobTypeCount> findJobTypeCountByProductId(Long productId);
+}

backend/src/main/java/com/woowacourse/f12/domain/review/ReviewRepositoryCustomImpl.java

@@ -0,0 +1,39 @@
+package com.woowacourse.f12.domain.review;
+
+import static com.woowacourse.f12.domain.member.QMember.member;
+import static com.woowacourse.f12.domain.review.QReview.review;
+
+import com.querydsl.jpa.impl.JPAQueryFactory;
+import com.woowacourse.f12.domain.product.Product;
+import java.util.List;
+import org.springframework.data.jpa.repository.support.QuerydslRepositorySupport;
+
+public class ReviewRepositoryCustomImpl extends QuerydslRepositorySupport implements ReviewRepositoryCustom {
+
+    private final JPAQueryFactory jpaQueryFactory;
+
+    public ReviewRepositoryCustomImpl(final JPAQueryFactory jpaQueryFactory) {
+        super(Product.class);
+        this.jpaQueryFactory = jpaQueryFactory;
+    }
+
+    @Override
+    public List<CareerLevelCount> findCareerLevelCountByProductId(final Long productId) {
+        return jpaQueryFactory.select(new QCareerLevelCount(member.careerLevel, member.id.count()))
+                .from(review)
+                .innerJoin(review.member, member)
+                .where(review.product.id.eq(productId))
+                .groupBy(member.careerLevel)
+                .fetch();
+    }
+
+    @Override
+    public List<JobTypeCount> findJobTypeCountByProductId(final Long productId) {
+        return jpaQueryFactory.select(new QJobTypeCount(member.jobType, member.id.count()))
+                .from(review)
+                .innerJoin(review.member, member)
+                .where(review.product.id.eq(productId))
+                .groupBy(member.jobType)
+                .fetch();
+    }
+}

backend/src/main/java/com/woowacourse/f12/dto/request/member/MemberRequest.java

@@ -1,7 +1,7 @@
 package com.woowacourse.f12.dto.request.member;
 
-import com.woowacourse.f12.dto.CareerLevelConstant;
-import com.woowacourse.f12.dto.JobTypeConstant;
+import com.woowacourse.f12.presentation.member.CareerLevelConstant;
+import com.woowacourse.f12.presentation.member.JobTypeConstant;
 import javax.validation.constraints.NotNull;
 import lombok.Getter;