[Step1] 🚀 1단계 - 지하철 구간 추가 기능 개선

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

@@ -4,6 +4,7 @@
 import nextstep.subway.line.dto.CreateLineRequest;
 import nextstep.subway.line.dto.LineResponse;
 import nextstep.subway.line.dto.UpdateLineRequest;
+import nextstep.subway.line.repository.Line;
 import nextstep.subway.line.service.LineService;
 import nextstep.subway.section.dto.CreateSectionRequest;
 import org.springframework.http.ResponseEntity;

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

@@ -6,6 +6,7 @@
 import nextstep.subway.line.repository.Line;
 import nextstep.subway.line.repository.LineRepository;
 import nextstep.subway.section.dto.CreateSectionRequest;
+import nextstep.subway.section.policy.add.AddSectionPolicy;
 import nextstep.subway.section.repository.Section;
 import nextstep.subway.station.repository.Station;
 import nextstep.subway.station.service.StationFindable;
@@ -21,6 +22,7 @@
 class LineService implements LineFindable, LineSavable, LineUpdatable, LineDeletable {
     private final LineRepository lineRepository;
     private final StationFindable stationFindable;
+    private final AddSectionPolicy addSectionPolicy;
 
     @Transactional
     public Line saveLine(CreateLineRequest request) {
@@ -56,9 +58,10 @@ public void deleteLineById(Long id) {
     @Transactional
     public Line addSection(Long id, CreateSectionRequest request) {
         Line line = findLineById(id);
-        System.out.println(line.getSections().size());
-        line.getSections().addSection(createSection(request.getUpStationId(), request.getDownStationId(), request.getDistance()));
-        System.out.println(line.getSections().size());
+        line.getSections().addSection(
+                createSection(request.getUpStationId(), request.getDownStationId(), request.getDistance()),
+                addSectionPolicy
+        );
         return line;
     }
 

src/main/java/nextstep/subway/section/config/BeanConfig.java

@@ -0,0 +1,19 @@
+package nextstep.subway.section.config;
+
+import nextstep.subway.section.policy.add.*;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+import java.util.List;
+
+@Configuration
+public class BeanConfig {
+    @Bean
+    AddSectionPolicy addSectionPolicy() {
+        return new IntegrationAddSectionPolicy(List.of(
+                new CheckRegisterPolicy(),
+                new CheckNotRegisterPolicy(),
+                new CheckDistancePolicy()
+        ));
+    }
+}

src/main/java/nextstep/subway/section/policy/add/AddSectionPolicy.java

@@ -0,0 +1,8 @@
+package nextstep.subway.section.policy.add;
+
+import nextstep.subway.section.repository.Section;
+import nextstep.subway.section.repository.Sections;
+
+public interface AddSectionPolicy {
+    void validate(Sections sections, Section section);
+}

src/main/java/nextstep/subway/section/policy/add/CheckDistancePolicy.java

@@ -0,0 +1,19 @@
+package nextstep.subway.section.policy.add;
+
+import nextstep.subway.section.repository.Section;
+import nextstep.subway.section.repository.Sections;
+
+import java.util.Optional;
+
+public class CheckDistancePolicy implements AddSectionPolicy {
+    @Override
+    public void validate(Sections sections, Section section) {
+        Optional<Section> sectionEqualUpStation = sections.getSectionByUpStation(section.getUpStation());
+        Optional<Section> sectionEqualDownStation = sections.getSectionByDownStation(section.getDownStation());
+
+        if ((sectionEqualUpStation.isPresent() && (sectionEqualUpStation.get().getDistance() <= section.getDistance()))
+                || (sectionEqualDownStation.isPresent() && (sectionEqualDownStation.get().getDistance() <= section.getDistance()))) {
+            throw new RuntimeException("Section's distance too long");
+        }
+    }
+}

src/main/java/nextstep/subway/section/policy/add/CheckNotRegisterPolicy.java

@@ -0,0 +1,24 @@
+package nextstep.subway.section.policy.add;
+
+import nextstep.subway.section.repository.Section;
+import nextstep.subway.section.repository.Sections;
+import nextstep.subway.station.repository.Station;
+
+import java.util.Objects;
+import java.util.Optional;
+
+public class CheckNotRegisterPolicy implements AddSectionPolicy {
+    @Override
+    public void validate(Sections sections, Section section) {
+        Optional<Station> upStation = sections.getAllStation().stream()
+                .filter(station -> Objects.equals(station, section.getUpStation()))
+                .findFirst();
+        Optional<Station> downStation = sections.getAllStation().stream()
+                .filter(station -> Objects.equals(station, section.getDownStation()))
+                .findFirst();
+
+        if (upStation.isEmpty() && downStation.isEmpty()) {
+            throw new RuntimeException("Section's stations not exist in sections");
+        }
+    }
+}

src/main/java/nextstep/subway/section/policy/add/CheckRegisterPolicy.java

@@ -0,0 +1,24 @@
+package nextstep.subway.section.policy.add;
+
+import nextstep.subway.section.repository.Section;
+import nextstep.subway.section.repository.Sections;
+import nextstep.subway.station.repository.Station;
+
+import java.util.Objects;
+import java.util.Optional;
+
+public class CheckRegisterPolicy implements AddSectionPolicy {
+    @Override
+    public void validate(Sections sections, Section section) {
+        Optional<Station> upStation = sections.getAllStation().stream()
+                .filter(station -> Objects.equals(station, section.getUpStation()))
+                .findFirst();
+        Optional<Station> downStation = sections.getAllStation().stream()
+                .filter(station -> Objects.equals(station, section.getDownStation()))
+                .findFirst();
+
+        if (upStation.isPresent() && downStation.isPresent()) {
+            throw new RuntimeException("Section's stations already registered");
+        }
+    }
+}

src/main/java/nextstep/subway/section/policy/add/IntegrationAddSectionPolicy.java

@@ -0,0 +1,16 @@
+package nextstep.subway.section.policy.add;
+
+import lombok.RequiredArgsConstructor;
+import nextstep.subway.section.repository.Section;
+import nextstep.subway.section.repository.Sections;
+
+import java.util.List;
+
+@RequiredArgsConstructor
+public class IntegrationAddSectionPolicy implements AddSectionPolicy {
+    private final List<AddSectionPolicy> policyList;
+
+    public void validate(Sections sections, Section section) {
+        policyList.forEach(addSectionPolicy -> addSectionPolicy.validate(sections, section));
+    }
+}

src/main/java/nextstep/subway/section/policy/DeleteSectionPolicy.java → src/main/java/nextstep/subway/section/policy/delete/DeleteSectionPolicy.java

@@ -1,4 +1,4 @@
-package nextstep.subway.section.policy;
+package nextstep.subway.section.policy.delete;
 
 import nextstep.subway.section.repository.Sections;
 import nextstep.subway.station.repository.Station;

src/main/java/nextstep/subway/section/repository/Section.java

@@ -1,9 +1,6 @@
 package nextstep.subway.section.repository;
 
-import lombok.AccessLevel;
-import lombok.Builder;
-import lombok.Getter;
-import lombok.NoArgsConstructor;
+import lombok.*;
 import nextstep.subway.station.repository.Station;
 
 import javax.persistence.*;

src/main/java/nextstep/subway/section/repository/Sections.java

@@ -1,34 +1,53 @@
 package nextstep.subway.section.repository;
 
 import lombok.AccessLevel;
+import lombok.Getter;
 import lombok.NoArgsConstructor;
-import nextstep.subway.section.policy.AddSectionPolicy;
-import nextstep.subway.section.policy.DeleteSectionPolicy;
+import nextstep.subway.section.policy.add.AddSectionPolicy;
+import nextstep.subway.section.policy.delete.DeleteSectionPolicy;
 import nextstep.subway.station.repository.Station;
 
 import javax.persistence.CascadeType;
 import javax.persistence.Embeddable;
 import javax.persistence.JoinColumn;
 import javax.persistence.OneToMany;
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.List;
-import java.util.stream.Collectors;
+import java.util.*;
 
 @Embeddable
 @NoArgsConstructor(access = AccessLevel.PROTECTED)
 public class Sections {
-    @OneToMany(cascade = {CascadeType.PERSIST, CascadeType.REMOVE})
+    @OneToMany(cascade = {CascadeType.PERSIST, CascadeType.REMOVE}, orphanRemoval = true)
     @JoinColumn(name = "line_id")
     private List<Section> sections = new ArrayList<>();
 
-    public void addSection(Section section) {
-        AddSectionPolicy.validate(this, section);
+    @Getter
+    private Long firstStationId;
+
+    @Getter
+    private Long lastStationId;
+
+    public void addSection(Section section, AddSectionPolicy policy) {
+        policy.validate(this, section);
+        Optional<Station> upStation = getAllStation().stream()
+                .filter(station -> Objects.equals(station, section.getUpStation()))
+                .findFirst();
+        Optional<Station> downStation = getAllStation().stream()
+                .filter(station -> Objects.equals(station, section.getDownStation()))
+                .findFirst();
+
+        if (upStation.isPresent() && upStation.get().getId().equals(lastStationId)) {
+            lastStationId = section.getDownStation().getId();
+        }
+        if (downStation.isPresent() && downStation.get().getId().equals(firstStationId)) {
+            firstStationId = section.getUpStation().getId();
+        }
+
         this.sections.add(section);
     }
 
     public void deleteSectionByLastStation(Station station) {
         DeleteSectionPolicy.validate(this, station);
+        this.lastStationId = getLastSection().getUpStation().getId();
         this.sections.remove(getLastSection());
     }
 
@@ -40,6 +59,14 @@ public Section getLastSection() {
         return this.sections.get(this.sections.size() - 1);
     }
 
+    public Optional<Section> getSectionByUpStation(Station upStation) {
+        return this.sections.stream().filter(section -> Objects.equals(section.getUpStation(), upStation)).findFirst();
+    }
+
+    public Optional<Section> getSectionByDownStation(Station downStation) {
+        return this.sections.stream().filter(section -> Objects.equals(section.getDownStation(), downStation)).findFirst();
+    }
+
     public Station getDownEndStation() {
         return this.sections.get(this.sections.size() - 1).getDownStation();
     }
@@ -49,15 +76,33 @@ public Long getTotalDistance() {
     }
 
     public List<Station> getAllStation() {
-        List<Station> totalStation = this.sections.stream().map(Section::getUpStation).collect(Collectors.toList());
-        totalStation.add(this.sections.get(this.sections.size() - 1).getDownStation());
-        return Collections.unmodifiableList(totalStation);
+        List<Station> result = new ArrayList<>();
+        Long targetStationId = firstStationId;
+
+        while (targetStationId != null && !targetStationId.equals(lastStationId)) {
+            for (Section section : sections) {
+                if (Objects.equals(section.getUpStation().getId(), targetStationId)) {
+                    result.add(section.getUpStation());
+                    targetStationId = section.getDownStation().getId();
+                }
+                if (targetStationId.equals(lastStationId)) {
+                    result.add(section.getDownStation());
+                    break;
+                }
+            }
+        }
+
+        return Collections.unmodifiableList(result);
     }
 
     public Sections(List<Section> sections) {
         if (sections.isEmpty()) {
             throw new RuntimeException("sections: at least one section is required");
         }
         this.sections = sections;
+        this.firstStationId = sections.get(0).getUpStation().getId();
+        this.lastStationId = sections.get(sections.size() - 1).getDownStation().getId();
     }
+
+
 }

src/test/java/nextstep/subway/unit/fixture/LineFixture.java → src/test/java/nextstep/fixture/LineFixture.java

@@ -1,9 +1,7 @@
-package nextstep.subway.unit.fixture;
+package nextstep.fixture;
 
 import nextstep.subway.line.repository.Line;
 
-import static nextstep.subway.unit.fixture.SectionFixture.강남역_TO_신논현역;
-
 public class LineFixture {
     public static final Long 신분당선_ID = 1L;
 
@@ -12,7 +10,7 @@ public class LineFixture {
                 .builder()
                 .name("신분당선")
                 .color("bg-red-600")
-                .initSection(강남역_TO_신논현역())
+                .initSection(SectionFixture.강남역_TO_신논현역())
                 .build();
     }
 }

src/test/java/nextstep/subway/unit/fixture/SectionFixture.java → src/test/java/nextstep/fixture/SectionFixture.java

@@ -1,4 +1,4 @@
-package nextstep.subway.unit.fixture;
+package nextstep.fixture;
 
 import nextstep.subway.section.repository.Section;
 

src/test/java/nextstep/subway/unit/fixture/StationFixture.java → src/test/java/nextstep/fixture/StationFixture.java

@@ -1,4 +1,4 @@
-package nextstep.subway.unit.fixture;
+package nextstep.fixture;
 
 import nextstep.subway.station.repository.Station;
 

src/test/java/nextstep/subway/acceptance/section/SectionAcceptanceTest.java

@@ -35,6 +35,8 @@ void init() {
         CREATE_LINE_URL = createdResponse.header("Location");
     }
 
+    // TODO: 구간 추가에 대한 상세 사항은 Policy 의 단위 테스트에서 검증한다.
+
     /**
      * When 지하철 구간을 추가하면
      * Then 지하철 노선 조회시, 추가된 구간을 확인할 수 있다
@@ -49,32 +51,6 @@ void createSection() {
         추가한_구간이_노선에_포함된다(createdResponse, selectedResponse);
     }
 
-    /**
-     * Given 하행역이 지하철 노선에 등록된 구간으로
-     * When 구간을 등록하면
-     * Then 에러가 발생한다
-     */
-    @DisplayName("하행역이 이미 지하철 노선에 등록된 지하철 구간을 추가하면 에러가 발생한다.")
-    @Test
-    void createSection_already_register() {
-        CreateSectionRequest request = 하행역이_지하철_노선에_등록된_구간에_대한_요청이_존재한다();
-
-        구간을_등록하면_에러가_발생한다(request);
-    }
-
-    /**
-     * Given 상행역이 노선의 하행 종점역이 아닌 구간으로
-     * When 구간을 등록하면
-     * Then 에러가 발생한다
-     */
-    @DisplayName("상행역이 노선의 하행 종점역이 아닌 지하철 구간을 추가하면 에러가 발생한다.")
-    @Test
-    void createSection_not_include() {
-        CreateSectionRequest request = 상행역이_노선의_하행_종점역이_아닌_구간에_대한_요청이_존재한다();
-
-        구간을_등록하면_에러가_발생한다(request);
-    }
-
     /**
      * Given 새로운 지하철 구간을 추가하고
      * When 해당 노선의 구간을 제거하면
@@ -83,11 +59,8 @@ void createSection_not_include() {
     @DisplayName("지하철 구간을 삭제한다.")
     @Test
     void deleteSection() {
-        ExtractableResponse<Response> selectedResponse = 지하철_노선을_조회한다();
         ExtractableResponse<Response> createdResponse = 지하철_구간을_추가한다(UP_STATION_ID, DOWN_STATION_ID, DISTANCE);
-
         지하철_구간을_삭제한다(createdResponse.header("Location") + "/sections?stationId=" + DOWN_STATION_ID);
-
         삭제한_구간의_역이_노선에서_제외된다();
     }