feat: add api to view notification individually

- retrieving all unread notifications will not affect read status of notifications
- retrieving individual notifications require verification process for whether the retriever is the receiver of the notification

src/main/java/org/poolc/api/notification/controller/NotificationController.java

@@ -10,6 +10,8 @@
 import org.springframework.security.core.annotation.AuthenticationPrincipal;
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestMapping;
 
 import java.util.List;
@@ -21,15 +23,15 @@
 public class NotificationController {
     private final NotificationService notificationService;
 
+    @PostMapping("/{notificationId}")
+    public ResponseEntity<NotificationResponse> viewNotification(@AuthenticationPrincipal Member member, @PathVariable("notificationId") Long notificationId) {
+        NotificationResponse response = notificationService.readNotification(member, notificationId);
+        return ResponseEntity.status(HttpStatus.OK).body(response);
+    }
+
     @GetMapping("/unread")
     public ResponseEntity<List<NotificationResponse>> getUnreadNotifications(@AuthenticationPrincipal Member member) {
-        List<Notification> notifications = notificationService.getUnreadNotificationsForMember(member.getLoginID());
-        if (notifications.isEmpty()) {
-            return ResponseEntity.status(HttpStatus.NO_CONTENT).build();
-        }
-        List<NotificationResponse> responses = notifications.stream()
-                .map(NotificationResponse::of)
-                .collect(Collectors.toList());
+        List<NotificationResponse> responses = notificationService.getUnreadNotificationsForMember(member.getLoginID());
         return ResponseEntity.status(HttpStatus.OK).body(responses);
     }
 

src/main/java/org/poolc/api/notification/service/NotificationService.java

@@ -6,6 +6,8 @@
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
+
+import org.poolc.api.notification.dto.NotificationResponse;
 import org.springframework.transaction.annotation.Transactional;
 import lombok.RequiredArgsConstructor;
 import org.poolc.api.member.domain.Member;
@@ -27,15 +29,12 @@ public class NotificationService {
     private final MemberRepository memberRepository;
 
     @Transactional
-    public List<Notification> getUnreadNotificationsForMember(String receiverId) {
-        List<Notification> notifications = notificationRepository.findByReceiverIdAndReadStatus(receiverId, false)
+    public List<NotificationResponse> getUnreadNotificationsForMember(String receiverId) {
+        return notificationRepository.findByReceiverIdAndReadStatus(receiverId, false)
                 .stream()
                 .sorted(Comparator.comparing(Notification::getCreatedAt).reversed())
+                .map(NotificationResponse::of)
                 .collect(Collectors.toList());
-        notifications.forEach(Notification::memberReads);
-        Member recipient = getMemberByLoginID(receiverId);
-        recipient.resetNotificationCount();
-        return notifications;
     }
 
     @Transactional
@@ -85,15 +84,21 @@ public void createRecommentNotification(String senderId, String receiverId, Long
         receiver.addNotification();
     }
 
-    @Transactional(readOnly = true)
-    public void readNotification(Long notificationId) {
+    @Transactional
+    public NotificationResponse readNotification(Member member, Long notificationId) {
         Notification notification = notificationRepository.findById(notificationId)
                 .orElseThrow(() -> new NoSuchElementException("No notification found with given id."));
+        checkIfSelf(member, notification);
         notification.memberReads();
+        return NotificationResponse.of(notification);
     }
 
     private Member getMemberByLoginID(String loginID) {
         return memberRepository.findByLoginID(loginID)
                 .orElseThrow(() -> new NoSuchElementException("No user found with given loginID"));
     }
+
+    private void checkIfSelf(Member member, Notification notification) {
+        if (!notification.getReceiverId().equals(member.getLoginID())) throw new NoSuchElementException("No notification found.");
+    }
 }