Order Service

Overview

The Order Service handles core order processing for the shopping mall and acts as a distributed transaction orchestrator using the SAGA pattern.

Item	Details
Language	Java 17
Framework	Spring Boot 3.2
Database	Aurora PostgreSQL (Global Database)
Namespace	mall-order
Port	8080
Health Check	/actuator/health

Architecture

API Endpoints

Method	Path	Description
POST	/api/v1/orders	Create order
GET	/api/v1/orders/{id}	Get order
GET	/api/v1/orders?userId={userId}	Get orders by user
PUT	/api/v1/orders/{id}/cancel	Cancel order

Create Order

POST /api/v1/orders

Request:

{
  "userId": "user-123",
  "items": [
    {
      "productId": "prod-001",
      "sku": "SKU-ELECTRONICS-001",
      "quantity": 2,
      "price": 299000.00
    },
    {
      "productId": "prod-002",
      "sku": "SKU-FASHION-001",
      "quantity": 1,
      "price": 89000.00
    }
  ]
}

Response (201 Created):

{
  "id": "550e8400-e29b-41d4-a716-446655440000",
  "userId": "user-123",
  "status": "PENDING",
  "totalAmount": 687000.00,
  "items": [
    {
      "id": "item-uuid-1",
      "productId": "prod-001",
      "sku": "SKU-ELECTRONICS-001",
      "quantity": 2,
      "price": 299000.00
    },
    {
      "id": "item-uuid-2",
      "productId": "prod-002",
      "sku": "SKU-FASHION-001",
      "quantity": 1,
      "price": 89000.00
    }
  ],
  "createdAt": "2024-01-15T10:30:00",
  "updatedAt": "2024-01-15T10:30:00"
}

Get Order

GET /api/v1/orders/{id}

Response (200 OK):

{
  "id": "550e8400-e29b-41d4-a716-446655440000",
  "userId": "user-123",
  "status": "CONFIRMED",
  "totalAmount": 687000.00,
  "items": [...],
  "createdAt": "2024-01-15T10:30:00",
  "updatedAt": "2024-01-15T10:35:00"
}

Cancel Order

PUT /api/v1/orders/{id}/cancel

Response (200 OK):

{
  "id": "550e8400-e29b-41d4-a716-446655440000",
  "userId": "user-123",
  "status": "CANCELLED",
  "totalAmount": 687000.00,
  "items": [...],
  "createdAt": "2024-01-15T10:30:00",
  "updatedAt": "2024-01-15T11:00:00"
}

Data Models

Order Entity

@Entity
@Table(name = "orders")
public class Order {
    @Id
    @GeneratedValue(strategy = GenerationType.UUID)
    private UUID id;

    @Column(name = "user_id", nullable = false)
    private String userId;

    @Enumerated(EnumType.STRING)
    @Column(nullable = false)
    private OrderStatus status = OrderStatus.PENDING;

    @Column(name = "total_amount", precision = 12, scale = 2)
    private BigDecimal totalAmount = BigDecimal.ZERO;

    @OneToMany(mappedBy = "order", cascade = CascadeType.ALL)
    private List<OrderItem> items = new ArrayList<>();

    @Column(name = "created_at")
    private LocalDateTime createdAt;

    @Column(name = "updated_at")
    private LocalDateTime updatedAt;
}

OrderItem Entity

@Entity
@Table(name = "order_items")
public class OrderItem {
    @Id
    @GeneratedValue(strategy = GenerationType.UUID)
    private UUID id;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "order_id")
    private Order order;

    @Column(name = "product_id", nullable = false)
    private String productId;

    @Column(nullable = false)
    private String sku;

    @Column(nullable = false)
    private Integer quantity;

    @Column(precision = 12, scale = 2, nullable = false)
    private BigDecimal price;
}

OrderStatus Enum

public enum OrderStatus {
    PENDING,    // Pending
    CONFIRMED,  // Confirmed
    CANCELLED,  // Cancelled
    FAILED      // Failed
}

Database Schema

CREATE TABLE orders (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    user_id VARCHAR(255) NOT NULL,
    status VARCHAR(50) NOT NULL DEFAULT 'PENDING',
    total_amount DECIMAL(12, 2) DEFAULT 0,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE order_items (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    order_id UUID REFERENCES orders(id),
    product_id VARCHAR(255) NOT NULL,
    sku VARCHAR(255) NOT NULL,
    quantity INTEGER NOT NULL,
    price DECIMAL(12, 2) NOT NULL
);

CREATE INDEX idx_orders_user_id ON orders(user_id);
CREATE INDEX idx_orders_status ON orders(status);
CREATE INDEX idx_order_items_order_id ON order_items(order_id);

Events (Kafka)

Published Topics

Topic Name	Event	Description
orders.created	order.created	Published when order is created
orders.confirmed	order.confirmed	Published when order is confirmed after payment
orders.cancelled	order.cancelled	Published when order is cancelled

orders.created Payload

{
  "event": "order.created",
  "order": {
    "id": "550e8400-e29b-41d4-a716-446655440000",
    "userId": "user-123",
    "status": "PENDING",
    "totalAmount": 687000.00,
    "items": [...],
    "createdAt": "2024-01-15T10:30:00",
    "updatedAt": "2024-01-15T10:30:00"
  }
}

orders.confirmed Payload

{
  "event": "order.confirmed",
  "order": {
    "id": "550e8400-e29b-41d4-a716-446655440000",
    "userId": "user-123",
    "status": "CONFIRMED",
    "totalAmount": 687000.00,
    "items": [...],
    "createdAt": "2024-01-15T10:30:00",
    "updatedAt": "2024-01-15T10:35:00"
  }
}

Subscribed Topics

Topic Name	Description
payments.completed	Receives payment completion events to confirm orders

Environment Variables

Variable	Description	Default
SPRING_DATASOURCE_URL	Aurora PostgreSQL connection URL	-
SPRING_DATASOURCE_USERNAME	DB username	-
SPRING_DATASOURCE_PASSWORD	DB password	-
SPRING_KAFKA_BOOTSTRAP_SERVERS	Kafka broker address	-
SERVER_PORT	Service port	8080

Service Dependencies

SAGA Pattern

The Order Service uses the SAGA orchestrator pattern for distributed transactions:

1. Order Creation: Create order with PENDING status
2. Inventory Check: Request inventory reservation from Inventory Service
3. Payment Processing: Request payment from Payment Service
4. Order Confirmation: Change to CONFIRMED status when all steps succeed
5. Compensating Transaction: Rollback previous steps on failure

Error Handling

HTTP Status Code	Error	Description
404	OrderNotFoundException	Order not found
400	IllegalStateException	Invalid state transition (e.g., cancelling already cancelled order)
500	SagaException	SAGA transaction failure