feat: 알림 및 전송 도메인 구현

src/main/java/com/backendsystemdesignlab/notification/notification/domain/DeliveryStatus.java

@@ -0,0 +1,7 @@
+package com.backendsystemdesignlab.notification.notification.domain;
+
+public enum DeliveryStatus {
+    PENDING,
+    SENT,
+    FAILED
+}

src/main/java/com/backendsystemdesignlab/notification/notification/domain/Notification.java

@@ -0,0 +1,80 @@
+package com.backendsystemdesignlab.notification.notification.domain;
+
+import com.backendsystemdesignlab.notification.user.domain.User;
+import jakarta.persistence.*;
+
+import java.time.LocalDateTime;
+
+@Entity
+@Table(
+        name = "notifications",
+        uniqueConstraints = {
+                @UniqueConstraint(
+                        name = "uk_notification_event_id",
+                        columnNames = "event_id"
+                )
+        }
+)
+public class Notification {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @Column(name = "event_id", nullable = false, length = 100)
+    private String eventId;
+
+    @ManyToOne(fetch = FetchType.LAZY, optional = false)
+    @JoinColumn(name = "user_id", nullable = false)
+    private User user;
+
+    @Enumerated(EnumType.STRING)
+    @Column(nullable = false, length = 20)
+    private NotificationStatus status;
+
+    @Column(nullable = false, updatable = false)
+    private LocalDateTime createdAt;
+
+    protected Notification() {}
+
+    public Notification(String eventId, User user) {
+        this.eventId = eventId;
+        this.user = user;
+        this.status = NotificationStatus.PENDING;
+        this.createdAt = LocalDateTime.now();
+    }
+
+    public void startProcessing() {
+        this.status = NotificationStatus.PROCESSING;
+    }
+
+    public void complete() {
+        this.status = NotificationStatus.COMPLETED;
+    }
+
+    public void fail() {
+        this.status = NotificationStatus.FAILED;
+    }
+
+    public Long getId() {
+        return id;
+    }
+    public void setId(Long id) {
+        this.id = id;
+    }
+    public String getEventId() {
+        return eventId;
+    }
+
+    public User getUser() {
+        return user;
+    }
+
+    public NotificationStatus getStatus() {
+        return status;
+    }
+
+    public LocalDateTime getCreatedAt() {
+        return createdAt;
+    }
+}

src/main/java/com/backendsystemdesignlab/notification/notification/domain/NotificationDelivery.java

@@ -0,0 +1,86 @@
+package com.backendsystemdesignlab.notification.notification.domain;
+
+import com.backendsystemdesignlab.notification.user.domain.NotificationChannel;
+import jakarta.persistence.*;
+
+import java.time.LocalDateTime;
+
+@Entity
+@Table(name = "notification_deliveries")
+public class NotificationDelivery {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @ManyToOne(fetch = FetchType.LAZY, optional = false)
+    @JoinColumn(name = "notification_id", nullable = false)
+    private Notification notification;
+
+    @Enumerated(EnumType.STRING)
+    @Column(nullable = false, length = 20)
+    private NotificationChannel channel;
+
+    @Column(nullable = false, length = 512)
+    private String destination;
+
+    @Enumerated(EnumType.STRING)
+    @Column(nullable = false, length = 20)
+    private DeliveryStatus status;
+
+    @Column(nullable = false)
+    private int attemptCount;
+
+    private LocalDateTime sentAt;
+
+    protected NotificationDelivery() {}
+
+    public NotificationDelivery(Notification notification, NotificationChannel channel, String destination) {
+        this.notification = notification;
+        this.channel = channel;
+        this.destination = destination;
+        this.status = DeliveryStatus.PENDING;
+        this.attemptCount = 0;
+    }
+
+    public void recordAttempt() {
+        this.attemptCount++;
+    }
+
+    public void markSent() {
+        this.status = DeliveryStatus.SENT;
+        this.sentAt = LocalDateTime.now();
+    }
+
+    public void markFailed() {
+        this.status = DeliveryStatus.FAILED;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public Notification getNotification() {
+        return notification;
+    }
+
+    public NotificationChannel getChannel() {
+        return channel;
+    }
+
+    public String getDestination() {
+        return destination;
+    }
+
+    public DeliveryStatus getStatus() {
+        return status;
+    }
+
+    public int getAttemptCount() {
+        return attemptCount;
+    }
+
+    public LocalDateTime getSentAt() {
+        return sentAt;
+    }
+}

src/main/java/com/backendsystemdesignlab/notification/notification/domain/NotificationStatus.java

@@ -0,0 +1,8 @@
+package com.backendsystemdesignlab.notification.notification.domain;
+
+public enum NotificationStatus {
+    PENDING,    // 알림 생성
+    PROCESSING, // 실제 채널 전송 중
+    COMPLETED,  // 모든 필요한 전송 처리 완료
+    FAILED      // 알림 처리 실패
+}