step3

src/main/java/nextstep/courses/domain/Capacity.java

@@ -0,0 +1,22 @@
+package nextstep.courses.domain;
+
+import nextstep.courses.exception.BusinessInvalidValueException;
+
+public class Capacity {
+    private final int capacity;
+
+    public Capacity(int capacity) {
+        this.capacity = capacity;
+    }
+
+    public void validateCapacity(int count) {
+        if (count >= capacity) {
+            throw new BusinessInvalidValueException("최대수강인원을 초과했습니다.");
+        }
+    }
+
+    public int capacity() {
+         return capacity;
+    }
+}
+

src/main/java/nextstep/courses/domain/Course.java

@@ -1,25 +1,31 @@
 package nextstep.courses.domain;
 
+import nextstep.courses.utils.BaseEntity;
+
 import java.time.LocalDateTime;
 
-public class Course {
+public class Course extends BaseEntity {
     private Long id;
 
     private String title;
 
     private Long creatorId;
 
-    private LocalDateTime createdAt;
-
-    private LocalDateTime updatedAt;
-
     public Course() {
     }
 
+    public Course(Long id) {
+        this.id = id;
+    }
+
     public Course(String title, Long creatorId) {
         this(0L, title, creatorId, LocalDateTime.now(), null);
     }
 
+    public Course(Long id, String title, Long creatorId) {
+        this(id, title, creatorId, LocalDateTime.now(), null);
+    }
+
     public Course(Long id, String title, Long creatorId, LocalDateTime createdAt, LocalDateTime updatedAt) {
         this.id = id;
         this.title = title;
@@ -28,6 +34,10 @@ public Course(Long id, String title, Long creatorId, LocalDateTime createdAt, Lo
         this.updatedAt = updatedAt;
     }
 
+    public Long id() {
+        return id;
+    }
+
     public String getTitle() {
         return title;
     }

src/main/java/nextstep/courses/domain/Period.java

@@ -10,4 +10,12 @@ public Period(LocalDateTime beginDt, LocalDateTime endDt) {
         this.beginDt = beginDt;
         this.endDt = endDt;
     }
+
+    public LocalDateTime getBeginDt() {
+        return beginDt;
+    }
+
+    public LocalDateTime getEndDt() {
+        return endDt;
+    }
 }

src/main/java/nextstep/courses/domain/Price.java

@@ -0,0 +1,21 @@
+package nextstep.courses.domain;
+
+import nextstep.courses.exception.BusinessInvalidValueException;
+
+public class Price {
+    private final long price;
+
+    public Price(long price) {
+        this.price = price;
+    }
+
+    public void validatePrice(long price) {
+        if (this.price != price) {
+            throw new BusinessInvalidValueException("강의 가격이 변동되었습니다.");
+        }
+    }
+
+    public long price() {
+        return price;
+    }
+}

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

@@ -1,13 +1,50 @@
 package nextstep.courses.domain;
 
+import nextstep.courses.utils.BaseEntity;
 import nextstep.users.domain.NsUser;
 
-public class Registration {
+import java.time.LocalDateTime;
 
-    public Registration() {
+public class Registration extends BaseEntity {
+    private Long id = null;
+    private final NsUser user;
+    private final Session session;
+    private final Long amount;
+
+    public Registration(Long id, NsUser user, Session session, Long amount, LocalDateTime createdAt, LocalDateTime updatedAt) {
+        this.id = id;
+        this.user = user;
+        this.session = session;
+        this.amount = amount;
+        this.createdAt = createdAt;
+        this.updatedAt = updatedAt;
+    }
+
+    public Registration(NsUser user, Session session, Long amount) {
+        this.user = user;
+        this.session = session;
+        this.amount = amount;
     }
 
-    public void register(NsUser user, Session session, Long amount) {
+    public static Registration register(NsUser user, Session session, Long amount) {
+        Registration registration = new Registration(user, session, amount);
         session.enroll(user, amount);
+        return registration;
+    }
+
+    public Long id() {
+        return id;
+    }
+
+    public NsUser nsUser() {
+        return user;
+    }
+
+    public Session session() {
+        return session;
+    }
+
+    public Long amount() {
+        return amount;
     }
 }

src/main/java/nextstep/courses/domain/Semester.java

@@ -0,0 +1,11 @@
+package nextstep.courses.domain;
+
+import nextstep.courses.utils.BaseEntity;
+
+public class Semester extends BaseEntity {
+    private final Course course;
+
+    public Semester(Course course) {
+        this.course = course;
+    }
+}

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

@@ -2,40 +2,117 @@
 
 import nextstep.courses.enums.SessionStatus;
 import nextstep.courses.exception.BusinessInvalidValueException;
+import nextstep.courses.utils.BaseEntity;
 import nextstep.users.domain.NsUser;
 
 import java.time.LocalDateTime;
-import java.util.ArrayList;
 import java.util.List;
 
-public abstract class Session {
-    final Long id;
-    final Course course;
-    final SessionCover sessionCover;
-    final Period period;
-    SessionStatus status = SessionStatus.PREPARE;
-    final List<NsUser> participants = new ArrayList<>();
+public class Session extends BaseEntity {
+    public static long FREE_PRICE = 0L;
+    public static int MAX_CAPACITY = Integer.MAX_VALUE;
+    private final Long id;
+    private Course course;
+    private SessionCover sessionCover;
+    private Period period;
+    private Capacity capacity;
+    private Price price;
 
-    public Session(Long id, LocalDateTime beginDt, LocalDateTime endDt, SessionCover sessionCover, Course course) {
+    private SessionStatus status = SessionStatus.PREPARE;
+    private List<NsUser> participants;
+
+    public Session(Long id) {
+        this.id = id;
+    }
+
+    private Session(Long id, LocalDateTime beginDt, LocalDateTime endDt, SessionCover sessionCover, Course course, Capacity capacity, Price price, List<NsUser> participants) {
+        this.id = id;
+        this.period = new Period(beginDt, endDt);
+        this.sessionCover = sessionCover;
+        this.course = course;
+        this.capacity = capacity;
+        this.price = price;
+        this.participants = participants;
+    }
+
+    public Session(Long id, LocalDateTime beginDt, LocalDateTime endDt, SessionStatus status, Capacity capacity, Price price, Course course, SessionCover sessionCover, LocalDateTime createdAt, LocalDateTime updatedAt) {
         this.id = id;
         this.period = new Period(beginDt, endDt);
+        this.status = status;
         this.sessionCover = sessionCover;
         this.course = course;
+        this.capacity = capacity;
+        this.price = price;
+        this.createdAt = createdAt;
+        this.updatedAt = updatedAt;
     }
 
-    public abstract void enroll(NsUser participant, Long amount);
+    public static Session fromSessionForFree(Session session, SessionCover sessionCover, Course course, List<NsUser> participants) {
+        return Session.ofFree(session.id, session.period.getBeginDt(), session.period.getEndDt(), sessionCover, course, participants);
+    }
+
+    public static Session fromSessionForPaid(Session session, SessionCover sessionCover, Course course, List<NsUser> participants) {
+        return Session.ofPaid(session.id, session.period.getBeginDt(), session.period.getEndDt(), sessionCover, course, session.price.price(), session.capacity.capacity(), participants);
+    }
+
+    public static Session ofFree(Long id, LocalDateTime beginDt, LocalDateTime endDt, SessionCover sessionCover, Course course, List<NsUser> participants) {
+        return new Session(id, beginDt, endDt, sessionCover, course, new Capacity(MAX_CAPACITY), new Price(FREE_PRICE), participants);
+    }
+
+    public static Session ofPaid(Long id, LocalDateTime beginDt, LocalDateTime endDt, SessionCover sessionCover, Course course, Long price, Integer capacity, List<NsUser> participants) {
+        return new Session(id, beginDt, endDt, sessionCover, course, new Capacity(capacity), new Price(price), participants);
+    }
+
+    public static Session fromSession(Session session, SessionCover sessionCover, Course course, List<NsUser> participants) {
+        if (session.price.equals(0L)) {
+            return fromSessionForFree(session, sessionCover, course, participants);
+        }
+        return fromSessionForPaid(session, sessionCover, course, participants);
+    }
 
     public void startEnrollment() {
         this.status = SessionStatus.ENROLL;
     }
 
-    public void validateStatus() {
+    public void enroll(NsUser participant, Long amount) {
+        capacity.validateCapacity(participants.size());
+        price.validatePrice(amount);
+        validateStatus();
+        this.participants.add(participant);
+    }
+
+
+    private void validateStatus() {
         if (SessionStatus.ENROLL != this.status) {
             throw new BusinessInvalidValueException("수강신청 가능한 상태가 아닙니다.");
         }
     }
 
+    public Price price() {
+        return price;
+    }
+
+    public Capacity capacity() {
+        return capacity;
+    }
+
     public Long id() {
         return id;
     }
+
+    public Period period() {
+        return period;
+    }
+
+    public Course course() {
+        return course;
+    }
+
+    public SessionCover sessionCover() {
+        return sessionCover;
+    }
+
+    public String status() {
+        return this.status.name();
+    }
 }