🚀 3단계 - 수강신청(DB 적용) (#802)

* 🚀 3단계 - 수강신청(DB 적용)

* 도메인과 엔티티 사용 분리 및 JDBC사용 숨김

* register 로직 정리 진행

Author: Eundms

src/main/java/nextstep/courses/domain/image/SessionCoverImage.java

@@ -1,17 +1,41 @@
 package nextstep.courses.domain.image;
 
 public class SessionCoverImage {
+  private final Long id;
+  private final Long sessionId;
   private final SessionImageDimension dimension;
   private final SessionImageExtension extension;
   private final SessionImageCapacity capacity;
 
-  public SessionCoverImage(int width, int height, String extension, long bytes) {
-    this(new SessionImageDimension(width, height), SessionImageExtension.from(extension), new SessionImageCapacity(bytes));
+  public SessionCoverImage(Long sessionId, int width, int height, String extension, long bytes) {
+    this(null, sessionId, new SessionImageDimension(width, height), SessionImageExtension.from(extension), new SessionImageCapacity(bytes));
   }
 
-  public SessionCoverImage(SessionImageDimension dimension, SessionImageExtension extension, SessionImageCapacity capacity) {
+  public SessionCoverImage(Long id, Long sessionId, SessionImageDimension dimension, SessionImageExtension extension, SessionImageCapacity capacity) {
+    this.id = id;
+    this.sessionId = sessionId;
     this.dimension = dimension;
     this.extension = extension;
     this.capacity = capacity;
   }
+
+  public Long getId() {
+    return id;
+  }
+
+  public Long getSessionId() {
+    return sessionId;
+  }
+
+  public SessionImageDimension getDimension() {
+    return dimension;
+  }
+
+  public SessionImageExtension getExtension() {
+    return extension;
+  }
+
+  public SessionImageCapacity getCapacity() {
+    return capacity;
+  }
 }

src/main/java/nextstep/courses/domain/image/SessionImageCapacity.java

@@ -26,4 +26,7 @@ private void validate(long bytes) {
     }
   }
 
+  public long bytes() {
+    return bytes;
+  }
 }

src/main/java/nextstep/courses/domain/image/SessionImageDimension.java

@@ -15,6 +15,7 @@ public SessionImageDimension(int width, int height) {
     this.width = width;
     this.height = height;
   }
+
   private void validateMinLength(int width, int height){
     if(!(width >= MIN_WIDTH && height >= MIN_HEIGHT)) {
       throw new IllegalArgumentException("이미지는 가로 300이상, 세로 200 이상이어야 합니다.");
@@ -34,5 +35,11 @@ private int gcd(int a, int b) {
     return b == 0 ? a : gcd(b, a % b);
   }
 
+  public int width() {
+    return width;
+  }
 
+  public int height() {
+    return height;
+  }
 }

src/main/java/nextstep/courses/domain/image/SessionImageRepository.java

@@ -0,0 +1,9 @@
+package nextstep.courses.domain.image;
+
+public interface SessionImageRepository {
+    int save(SessionCoverImage image);
+
+    SessionCoverImage findById(Long id);
+
+    SessionCoverImage findBySessionId(Long sessionId);
+}

src/main/java/nextstep/courses/domain/registration/Registration.java

@@ -1,23 +1,42 @@
 package nextstep.courses.domain.registration;
 
 import java.time.LocalDateTime;
+import java.util.Objects;
 
 public class Registration {
+  private final Long id;
   private final Long sessionId;
   private final Long studentId;
   private final LocalDateTime enrolledAt;
 
   public Registration(Long sessionId, Long studentId) {
-    this(sessionId, studentId, LocalDateTime.now());
+    this(null, sessionId, studentId, LocalDateTime.now());
   }
 
-  public Registration(Long sessionId, Long studentId, LocalDateTime enrolledAt) {
+  public Registration(Long id, Long sessionId, Long studentId, LocalDateTime enrolledAt) {
+    this.id = id;
     this.sessionId = sessionId;
     this.studentId = studentId;
     this.enrolledAt = enrolledAt;
   }
+
   public boolean contains(Long studentId) {
-    return this.studentId == studentId;
+    return Objects.equals(this.studentId, studentId);
+  }
+
+  public Long getId() {
+    return id;
+  }
+
+  public Long getSessionId() {
+    return sessionId;
+  }
+
+  public Long getStudentId() {
+    return studentId;
   }
 
+  public LocalDateTime getEnrolledAt() {
+    return enrolledAt;
+  }
 }

src/main/java/nextstep/courses/domain/registration/RegistrationRepository.java

@@ -0,0 +1,13 @@
+package nextstep.courses.domain.registration;
+
+import java.util.List;
+
+public interface RegistrationRepository {
+    int save(Registration registration);
+
+    Registration findById(Long id);
+
+    List<Registration> findBySessionId(Long sessionId);
+
+    int countBySessionId(Long sessionId);
+}

src/main/java/nextstep/courses/domain/registration/Registrations.java

@@ -1,33 +1,44 @@
 package nextstep.courses.domain.registration;
 
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
 
 public class Registrations {
-  private final List<Registration> registrations;
-
-  public Registrations() {
-    this(new ArrayList<>());
-  }
-
-  public Registrations(List<Registration> registrations) {
-    this.registrations = registrations;
-  }
-
-  public Registrations add(Registration registration) {
-    List<Registration> newList = new ArrayList<>(registrations);
-    newList.add(registration);
-    return new Registrations(newList);
-  }
-
-  public int count() {
-    return registrations.size();
-  }
-
-  public boolean contains(Long studentId) {
-    return registrations.stream()
-        .anyMatch(r -> r.contains(studentId));
-  }
-
+    private final List<Registration> registrations;
+
+    public Registrations() {
+        this(new ArrayList<>());
+    }
+
+    public Registrations(List<Registration> registrations) {
+        this.registrations = new ArrayList<>(registrations);
+    }
+
+    public Registrations add(Registration registration) {
+        validateDuplicateRegistration(registration);
+        List<Registration> newList = new ArrayList<>(registrations);
+        newList.add(registration);
+        return new Registrations(newList);
+    }
+
+    private void validateDuplicateRegistration(Registration registration) {
+        if (isAlreadyRegistered(registration.getStudentId())) {
+            throw new IllegalArgumentException("이미 수강신청한 학생입니다.");
+        }
+    }
+
+    public boolean isAlreadyRegistered(long studentId) {
+        return registrations.stream()
+            .anyMatch(registration -> registration.getStudentId().equals(studentId));
+    }
+
+    public void validateCapacity(int maxCapacity) {
+        if (count() > maxCapacity) {
+            throw new IllegalStateException("최대 수강 인원을 초과할 수 없습니다.");
+        }
+    }
+
+    public int count() {
+        return registrations.size();
+    }
 }

src/main/java/nextstep/courses/domain/session/Enrollment.java

@@ -1,39 +1,33 @@
 package nextstep.courses.domain.session;
 
-import nextstep.courses.domain.session.type.FreeType;
-import nextstep.courses.domain.session.type.SessionType;
+import nextstep.courses.domain.registration.Registration;
+import nextstep.courses.domain.registration.Registrations;
 
 public class Enrollment {
-    private SessionState state;
-    private SessionType type;
-
-    public Enrollment() {
-        this(SessionState.PREPARING, new FreeType());
-    }
-
-    public Enrollment(SessionType type) {
-        this(SessionState.PREPARING, type);
-    }
-
-    public Enrollment(SessionState state, SessionType type) {
+    private final Session session;
+    private final SessionState state;
+    private final SessionPolicy policy;
+    private final Registrations registrations;
+
+    public Enrollment(Session session, SessionState state, SessionPolicy policy, Registrations registrations) {
+        validateState(state);
+        this.session = session;
         this.state = state;
-        this.type = type;
+        this.policy = policy;
+        this.registrations = registrations;
     }
 
-    public void enroll(long payAmount) {
-        validateState();
-        this.type = type.enroll(payAmount);
-    }
+    public Registration enroll(long payAmount, long userId) {
+        if (registrations.isAlreadyRegistered(userId)) {
+            throw new IllegalArgumentException("이미 수강신청한 학생입니다.");
+        }
 
-    public void open() {
-        this.state = state.open();
-    }
+        policy.validate(payAmount, registrations);
 
-    public void close() {
-        this.state = state.close();
+        return new Registration(session.getId(), userId);
     }
 
-    private void validateState() {
+    private void validateState(SessionState state) {
         if (!state.canEnroll()) {
             throw new IllegalStateException("모집중인 강의만 수강신청이 가능합니다.");
         }

src/main/java/nextstep/courses/domain/session/Session.java

@@ -1,38 +1,74 @@
 package nextstep.courses.domain.session;
 
+import java.util.List;
 import nextstep.courses.domain.BaseEntity;
-import nextstep.courses.domain.course.Course;
 import nextstep.courses.domain.image.SessionCoverImage;
+import nextstep.courses.domain.registration.Registration;
+import nextstep.courses.domain.registration.Registrations;
 
 public class Session extends BaseEntity {
-  private final Course course;
-  private final Term term;
-  private final SessionCoverImage cover;
-  private final SessionPeriod period;
-  private final Enrollment enrollment;
-
-  public Session(Course course, int term, SessionCoverImage cover, String startDay, String endDay) {
-    this(null, course, new Term(term), cover, new SessionPeriod(startDay, endDay), new Enrollment());
-  }
-
-  public Session(Long id, Course course, Term term, SessionCoverImage cover, SessionPeriod period, Enrollment enrollment) {
-    super(id);
-    this.course = course;
-    this.term = term;
-    this.cover = cover;
-    this.period = period;
-    this.enrollment = enrollment;
-  }
-
-  public void enroll(long payAmount) {
-    enrollment.enroll(payAmount);
-  }
-
-  public void open() {
-    enrollment.open();
-  }
-
-  public void close() {
-    enrollment.close();
-  }
+    private final Long courseId;
+    private final Term term;
+    private final SessionPeriod period;
+    private final SessionCoverImage coverImage;
+    private final SessionPolicy sessionPolicy;
+    private SessionState state;
+
+    public Session(Long courseId, int term, String startDay, String endDay, SessionCoverImage coverImage) {
+        this(null, courseId, new Term(term), new SessionPeriod(startDay, endDay), SessionState.PREPARING, new SessionPolicy(), coverImage);
+    }
+
+    public Session(Long courseId, int term, String startDay, String endDay, SessionPolicy sessionPolicy, SessionCoverImage coverImage) {
+        this(null, courseId, new Term(term), new SessionPeriod(startDay, endDay), SessionState.PREPARING, sessionPolicy, coverImage);
+    }
+
+    public Session(Long id, Long courseId, Term term, SessionPeriod period, SessionState state, SessionPolicy sessionPolicy, SessionCoverImage coverImage) {
+        super(id);
+        this.courseId = courseId;
+        this.term = term;
+        this.period = period;
+        this.state = state;
+        this.sessionPolicy = sessionPolicy;
+        this.coverImage = coverImage;
+    }
+
+    public Enrollment enrollment(Registrations registrations) {
+      return new Enrollment(this, state, sessionPolicy, registrations);
+    }
+
+    public Enrollment enrollment(List<Registration> registrations) {
+        return new Enrollment(this, state, sessionPolicy, new Registrations(registrations));
+    }
+
+    public void open() {
+        this.state = state.open();
+    }
+
+    public void close() {
+        this.state = state.close();
+    }
+
+    public Long getCourseId() {
+        return courseId;
+    }
+
+    public Term getTerm() {
+        return term;
+    }
+
+    public SessionPeriod getPeriod() {
+        return period;
+    }
+
+    public SessionState getState() {
+        return state;
+    }
+
+    public SessionPolicy getSessionPolicy() {
+        return sessionPolicy;
+    }
+
+    public SessionCoverImage getCoverImage() {
+        return coverImage;
+    }
 }

src/main/java/nextstep/courses/domain/session/SessionPeriod.java

@@ -21,4 +21,12 @@ private void validate(LocalDate startDay, LocalDate endDay) {
       throw new IllegalArgumentException("시작일은 종료일보다 이전이어야 합니다.");
     }
   }
+
+  public LocalDate startDay() {
+    return startDay;
+  }
+
+  public LocalDate endDay() {
+    return endDay;
+  }
 }