3단계 - 수강신청(DB 적용)

.gitignore

@@ -31,3 +31,5 @@ out/
 
 ### VS Code ###
 .vscode/
+
+/bin/

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

@@ -2,6 +2,9 @@
 
 import nextstep.payments.domain.Payment;
 
+import java.util.List;
+import java.util.stream.Collectors;
+
 public abstract class Session {
     protected Long id;
     protected String name;
@@ -18,6 +21,11 @@ public Session(Long id, String name, Period period, Image coverImage, SessionSta
         this.status = status;
         this.registeredStudents = new Students();
     }
+    public List<Long> getStudentIds() {
+        return registeredStudents.getStudents().stream()
+                .map(Student::getId)
+                .collect(Collectors.toList());
+    }
 
     public Students getRegisteredStudent() {
         return registeredStudents;

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

@@ -2,6 +2,7 @@
 
 import java.util.HashSet;
 import java.util.Set;
+import java.util.Collections;
 
 public class Students {
     private Set<Student> students = new HashSet<>();
@@ -25,4 +26,8 @@ public boolean contains(Student student) {
     public int size() {
         return students.size();
     }
+
+    public Set<Student> getStudents() {
+        return Collections.unmodifiableSet(students);
+    }
 }

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

@@ -16,6 +16,10 @@ public boolean isSameAmount(int amount) {
         return this.amount == amount;
     }
 
+    public int getValue() {
+        return amount;
+    }
+
     @Override
     public boolean equals(Object o) {
         if (this == o) return true;

src/main/java/nextstep/courses/infrastructure/JdbcSessionRepository.java

@@ -7,72 +7,116 @@
 import nextstep.courses.domain.PaidSession;
 import nextstep.courses.domain.FreeSession;
 
-import org.springframework.jdbc.core.JdbcTemplate;
+import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate;
+import org.springframework.jdbc.core.namedparam.MapSqlParameterSource;
 import org.springframework.jdbc.core.RowMapper;
 import org.springframework.jdbc.core.simple.SimpleJdbcInsert;
 import org.springframework.stereotype.Repository;
+import org.springframework.jdbc.core.JdbcTemplate;
+import org.springframework.transaction.annotation.Transactional;
 
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
 @Repository
 public class JdbcSessionRepository {
+    private final NamedParameterJdbcTemplate namedParameterJdbcTemplate;
     private final JdbcTemplate jdbcTemplate;
 
     public JdbcSessionRepository(JdbcTemplate jdbcTemplate) {
         this.jdbcTemplate = jdbcTemplate;
+        this.namedParameterJdbcTemplate = new NamedParameterJdbcTemplate(jdbcTemplate);
     }
 
+    @Transactional
     public void save(Session session, Long courseId) {
         Long imageId = null;
         if (session.getCoverImage() != null) {
             imageId = insertImage(session.getCoverImage());
         }
 
-        String sql = "insert into session (name, type, start_date, end_date, status, capacity, tuition_fee, image_id, course_id) " +
-                "values (?, ?, ?, ?, ?, ?, ?, ?, ?)";
-
-        jdbcTemplate.update(sql,
-                session.getName(),
-                session.getType().name(),
-                session.getPeriod().getStartDate(),
-                session.getPeriod().getEndDate(),
-                session.getStatus().name(),
-                session instanceof PaidSession ? ((PaidSession) session).getCapacity() : null,
-                session instanceof PaidSession ? ((PaidSession) session).getTuitionFee() : null,
-                imageId,
-                courseId
-        );
+        SimpleJdbcInsert insert = new SimpleJdbcInsert(jdbcTemplate)
+                .withTableName("session")
+                .usingGeneratedKeyColumns("id");
+
+        Map<String, Object> params = new HashMap<>();
+        params.put("name", session.getName());
+        params.put("type", session.getType().name());
+        params.put("start_date", session.getPeriod().getStartDate());
+        params.put("end_date", session.getPeriod().getEndDate());
+        params.put("status", session.getStatus().name());
+        params.put("capacity", session instanceof PaidSession ? ((PaidSession) session).getCapacity().getValue() : null);
+        params.put("tuition_fee", session instanceof PaidSession ? ((PaidSession) session).getTuitionFee().getValue() : null);
+        params.put("image_id", imageId);
+        params.put("course_id", courseId);
+
+        insert.execute(params);
+    }
+
+    @Transactional
+    public void registerStudent(Long sessionId, Long studentId) {
+        String sql = "insert into session_student (session_id, student_id) values (:sessionId, :studentId)";
+        MapSqlParameterSource params = new MapSqlParameterSource()
+                .addValue("sessionId", sessionId)
+                .addValue("studentId", studentId);
+        namedParameterJdbcTemplate.update(sql, params);
     }
 
     public List<Session> findAll() {
         String sql = "select s.*, i.file_name, i.content_type, i.size_in_bytes, i.width, i.height " +
                 "from session s left join image i on s.image_id = i.id";
-        return jdbcTemplate.query(sql, sessionRowMapper());
+        List<Session> sessions = namedParameterJdbcTemplate.query(sql, sessionRowMapper());
+
+        // 각 세션에 대한 수강생 정보를 함께 조회
+        for (Session session : sessions) {
+            List<Long> studentIds = findStudentIdsBySessionId(session.getId());
+            for (Long studentId : studentIds) {
+                session.register(studentId, null);
+            }
+        }
+        return sessions;
     }
 
     public Session findById(Long id) {
         String sql = "select s.*, i.file_name, i.content_type, i.size_in_bytes, i.width, i.height " +
-                "from session s left join image i on s.image_id = i.id where s.id = ?";
-        return jdbcTemplate.queryForObject(sql, sessionRowMapper(), id);
+                "from session s left join image i on s.image_id = i.id where s.id = :id";
+        Session session = namedParameterJdbcTemplate.queryForObject(sql, 
+            new MapSqlParameterSource("id", id), 
+            sessionRowMapper());
+
+        if (session != null) {
+            // 세션의 수강생 정보를 함께 조회
+            List<Long> studentIds = findStudentIdsBySessionId(id);
+            for (Long studentId : studentIds) {
+                session.register(studentId, null);
+            }
+        }
+        return session;
     }
 
+    @Transactional
     public void update(Session session) {
-        String sql = "update session set name = ?, start_date = ?, end_date = ?, status = ?, capacity = ?, tuition_fee = ? where id = ?";
-        jdbcTemplate.update(sql,
-                session.getName(),
-                session.getPeriod().getStartDate(),
-                session.getPeriod().getEndDate(),
-                session.getStatus().name(),
-                session instanceof PaidSession ? ((PaidSession) session).getCapacity() : null,
-                session instanceof PaidSession ? ((PaidSession) session).getTuitionFee() : null,
-                session.getId()
-        );
+        String sql = "update session set name = :name, start_date = :startDate, end_date = :endDate, " +
+                "status = :status, capacity = :capacity, tuition_fee = :tuitionFee where id = :id";
+
+        MapSqlParameterSource params = new MapSqlParameterSource()
+                .addValue("name", session.getName())
+                .addValue("startDate", session.getPeriod().getStartDate())
+                .addValue("endDate", session.getPeriod().getEndDate())
+                .addValue("status", session.getStatus().name())
+                .addValue("capacity", session instanceof PaidSession ? ((PaidSession) session).getCapacity().getValue() : null)
+                .addValue("tuitionFee", session instanceof PaidSession ? ((PaidSession) session).getTuitionFee().isSameAmount(0) ? 0 : null : null)
+                .addValue("id", session.getId());
+
+        namedParameterJdbcTemplate.update(sql, params);
     }
 
+    @Transactional
     public void deleteById(Long id) {
-        jdbcTemplate.update("delete from session where id = ?", id);
+        deleteAllStudentsBySessionId(id);
+        String sql = "delete from session where id = :id";
+        namedParameterJdbcTemplate.update(sql, new MapSqlParameterSource("id", id));
     }
 
     private Long insertImage(Image image) {
@@ -90,6 +134,18 @@ private Long insertImage(Image image) {
         return insert.executeAndReturnKey(params).longValue();
     }
 
+    private List<Long> findStudentIdsBySessionId(Long sessionId) {
+        String sql = "select student_id from session_student where session_id = :sessionId";
+        return namedParameterJdbcTemplate.query(sql,
+                new MapSqlParameterSource("sessionId", sessionId),
+                (rs, rowNum) -> rs.getLong("student_id"));
+    }
+
+    private void deleteAllStudentsBySessionId(Long sessionId) {
+        String sql = "delete from session_student where session_id = :sessionId";
+        namedParameterJdbcTemplate.update(sql, new MapSqlParameterSource("sessionId", sessionId));
+    }
+
     private RowMapper<Session> sessionRowMapper() {
         return (rs, rowNum) -> {
             SessionStatus status = SessionStatus.valueOf(rs.getString("status"));