🚀 3단계 - 지하철 구간 관리

build.gradle

@@ -31,7 +31,6 @@ dependencies {
     testImplementation 'io.rest-assured:rest-assured:4.5.1'
     testImplementation 'com.navercorp.fixturemonkey:fixture-monkey-starter:0.5.8'
     testImplementation 'com.google.guava:guava:16+'
-    testImplementation 'org.mockito:mockito-core'
 
     // mapstruct
     implementation 'org.mapstruct:mapstruct' + ":$mapstructVersion"

src/main/java/subway/common/Validation.java

@@ -0,0 +1,12 @@
+package subway.common;
+
+import java.util.Objects;
+import java.util.function.Consumer;
+
+public class Validation {
+    public static <V> void setIfNotNull(V value, Consumer<V> setter) {
+        if (Objects.nonNull(value)) {
+            setter.accept(value);
+        }
+    }
+}

src/main/java/subway/line/controller/LineController.java

@@ -9,6 +9,9 @@
 import subway.line.dto.ModifyLineRequest;
 import subway.line.dto.ModifyLineResponse;
 import subway.line.service.LineService;
+import subway.section.dto.AddSectionRequest;
+import subway.section.dto.AddSectionResponse;
+import subway.section.dto.SectionResponse;
 
 import java.util.List;
 
@@ -46,4 +49,23 @@ public ResponseEntity<Void> deleteLine(@PathVariable Long id) {
         lineService.deleteLine(id);
         return ResponseEntity.noContent().build();
     }
+
+    @PostMapping("/lines/{lineId}/sections")
+    public ResponseEntity<AddSectionResponse> addSection(@PathVariable Long lineId, @RequestBody AddSectionRequest addSectionRequest
+    ) {
+        AddSectionResponse addSectionResponse = lineService.addSection(lineId, addSectionRequest);
+        return ResponseEntity.status(HttpStatus.CREATED).body(addSectionResponse);
+    }
+
+    @GetMapping("/lines/{lineId}/sections")
+    public ResponseEntity<List<SectionResponse>> findSections(@PathVariable Long lineId) {
+        List<SectionResponse> sections = lineService.findSections(lineId);
+        return ResponseEntity.ok(sections);
+    }
+
+    @DeleteMapping("/lines/{lineId}/sections")
+    public ResponseEntity<Void> deleteSection(@PathVariable Long lineId, @RequestParam Long stationId) {
+        lineService.deleteSection(lineId, stationId);
+        return ResponseEntity.noContent().build();
+    }
 }

src/main/java/subway/line/domain/Line.java

@@ -21,6 +21,7 @@ public class Line extends BaseEntity {
     @Column(length = 20, nullable = false)
     private String name;
 
+    @Setter
     @Column(length = 20, nullable = false)
     private String color;
 
@@ -58,4 +59,8 @@ public void addSection(Section section) {
     public boolean hasLessThanTwoSections() {
         return sections.hasLessThanTwoSections();
     }
+
+    public boolean isTerminalStationId(Long id) {
+        return getTerminalStationId().equals(id);
+    }
 }

src/main/java/subway/line/domain/Sections.java

@@ -1,12 +1,15 @@
 package subway.line.domain;
 
+import subway.common.error.InvalidSectionRequestException;
 import subway.section.domain.Section;
 import subway.station.domain.Station;
 
 import javax.persistence.CascadeType;
 import javax.persistence.OneToMany;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
+import java.util.Objects;
 import java.util.stream.Stream;
 
 public class Sections {
@@ -29,8 +32,14 @@ public Section getLast() {
         return sections.get(sections.size() - 1);
     }
 
-    public void add(Section station) {
-        sections.add(station);
+    public void add(Section section) {
+        if (!sections.isEmpty()) {
+            validateUpStationId(section);
+            validateDownStationId(section);
+            validateDistance(section);
+        }
+
+        sections.add(section);
     }
 
     public List<Station> getStations() {
@@ -48,4 +57,37 @@ public Integer getTotalDistance() {
     public boolean hasLessThanTwoSections() {
         return sections.size() < 2;
     }
+
+    private void validateUpStationId(Section section) {
+        Line line = section.getLine();
+        Long upStationId = section.getUpStationId();
+
+        if (!Objects.equals(upStationId, line.getTerminalStationId())) {
+            throw new InvalidSectionRequestException("해당 노선의 하행종점역이 아닌 역이 상행역으로 설정되었습니다.",
+                    Map.of(
+                            "lineId", line.getId().toString(),
+                            "upStationId", upStationId.toString(),
+                            "downStationId", section.getDownStationId().toString()
+                    ));
+        }
+    }
+
+    private void validateDownStationId(Section section) {
+        Line line = section.getLine();
+        Station downStation = section.getDownStation();
+        if (line.getStations().contains(downStation)) {
+            throw new InvalidSectionRequestException("이미 노선에 등록된 역을 새로운 구간의 하행역으로 등록하였습니다.",
+                    Map.of(
+                            "lineId", line.getId().toString(),
+                            "upStationId", section.getUpStationId().toString(),
+                            "downStationId", section.getDownStationId().toString()
+                    ));
+        }
+    }
+
+    private void validateDistance(Section section) {
+        if (section.getDistance() < 1) {
+            throw new InvalidSectionRequestException("길이가 0인 구간은 등록할 수 없습니다.");
+        }
+    }
 }

src/main/java/subway/line/service/LineService.java

@@ -3,6 +3,7 @@
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
+import subway.common.error.InvalidSectionRequestException;
 import subway.common.error.NotFoundException;
 import subway.line.domain.Line;
 import subway.line.dto.CreateLineRequest;
@@ -11,19 +12,27 @@
 import subway.line.dto.ModifyLineResponse;
 import subway.line.repository.LineRepository;
 import subway.section.domain.Section;
+import subway.section.dto.AddSectionRequest;
+import subway.section.dto.AddSectionResponse;
+import subway.section.dto.SectionResponse;
+import subway.section.repository.SectionRepository;
 import subway.station.domain.Station;
 import subway.station.repository.StationRepository;
 
 import java.util.List;
+import java.util.Map;
 import java.util.stream.Collectors;
 
+import static subway.common.Validation.*;
 import static subway.line.mapper.LineMapper.LINE_MAPPER;
+import static subway.section.mapper.SectionMapper.SECTION_MAPPER;
 
 @Service
 @Transactional(readOnly = true)
 @RequiredArgsConstructor
 public class LineService {
     private final LineRepository lineRepository;
+    private final SectionRepository sectionRepository;
     private final StationRepository stationRepository;
 
     @Transactional
@@ -38,8 +47,8 @@ public LineResponse createLine(CreateLineRequest createLineRequest) {
     }
 
     public List<LineResponse> findAllLines() {
-        List<Line> lines = lineRepository.findAll();
-        return lines.stream()
+        return lineRepository.findAll()
+                .stream()
                 .map(LINE_MAPPER::toLineResponse)
                 .collect(Collectors.toList());
     }
@@ -52,9 +61,9 @@ public LineResponse findLine(Long id) {
     @Transactional
     public ModifyLineResponse modifyLine(Long id, ModifyLineRequest modifyLineRequest) {
         Line line = findLineById(id);
-        line.setName(modifyLineRequest.getName());
-        Line modifiedLine = lineRepository.save(line);
-        return LINE_MAPPER.toModifyLineResponse(modifiedLine);
+        setIfNotNull(modifyLineRequest.getName(), line::setName);
+        setIfNotNull(modifyLineRequest.getColor(), line::setColor);
+        return LINE_MAPPER.toModifyLineResponse(line);
     }
 
     @Transactional
@@ -65,6 +74,51 @@ public void deleteLine(Long id) {
         lineRepository.deleteById(id);
     }
 
+    @Transactional
+    public AddSectionResponse addSection(Long lineId, AddSectionRequest addSectionRequest) {
+        Line line = findLineById(lineId);
+        Station upStation = findStationById(addSectionRequest.getUpStationId());
+        Station downStation = findStationById(addSectionRequest.getDownStationId());
+
+        Section section = Section.builder()
+                .line(line)
+                .upStation(upStation)
+                .downStation(downStation)
+                .distance(addSectionRequest.getDistance())
+                .build();
+
+        line.addSection(section);
+        return SECTION_MAPPER.mapToCreateSectionResponse(section);
+    }
+
+    public List<SectionResponse> findSections(Long lineId) {
+        List<Section> sections = sectionRepository.findAllByLine_Id(lineId);
+        return sections.stream()
+                .map(SECTION_MAPPER::mapToSectionResponse)
+                .collect(Collectors.toList());
+    }
+
+    public void deleteSection(Long lineId, Long stationId) {
+        Line line = findLineById(lineId);
+
+        if (line.hasLessThanTwoSections()) {
+            throw new InvalidSectionRequestException("구간이 2개 이상일 때만 삭제할 수 있습니다.");
+        }
+
+        if (!line.isTerminalStationId(stationId)) {
+            throw new InvalidSectionRequestException("마지막 구간만 삭제할 수 있습니다.");
+        }
+
+        Section section = sectionRepository.findByLine_IdAndDownStation_Id(lineId, stationId)
+                .orElseThrow(() -> new NotFoundException(
+                        Map.of(
+                                "lineId", lineId.toString(),
+                                "stationId", stationId.toString()
+                        )));
+
+        sectionRepository.delete(section);
+    }
+
     private Line findLineById(Long id) {
         return lineRepository.findById(id).orElseThrow(() -> new NotFoundException(id));
     }

src/main/java/subway/section/dto/CreateSectionResponse.java → src/main/java/subway/section/dto/AddSectionRequest.java

@@ -9,7 +9,7 @@
 @AllArgsConstructor
 @NoArgsConstructor
 @Builder
-public class CreateSectionResponse {
+public class AddSectionRequest {
     private Long upStationId;
     private Long downStationId;
     private int distance;

src/main/java/subway/section/dto/AddSectionResponse.java

@@ -0,0 +1,16 @@
+package subway.section.dto;
+
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@AllArgsConstructor
+@NoArgsConstructor
+@Builder
+public class AddSectionResponse {
+    private Long upStationId;
+    private Long downStationId;
+    private int distance;
+}

src/main/java/subway/section/mapper/SectionMapper.java

@@ -13,7 +13,7 @@ public interface SectionMapper {
 
     @Mapping(target = "upStationId", source = "upStation.id")
     @Mapping(target = "downStationId", source = "downStation.id")
-    CreateSectionResponse mapToAddSectionResponse(Section section);
+    AddSectionResponse mapToCreateSectionResponse(Section section);
 
     @Mapping(target = "upStationId", source = "upStation.id")
     @Mapping(target = "downStationId", source = "downStation.id")