dt-jerald/microservice

Purpose and topology

This is a Maven multi-service e-commerce backend. Each top-level service is independently bootstrapped as a Spring application and exposes an HTTP controller/service/repository stack. No API gateway or frontend is present. Service discovery is a separate runtime.

• discovery-server/src/main/java/com/discovery_server/DiscoveryServerApplication.java

• cart-service/src/main/java/com/example/cart_service/CartServiceApplication.java

• order-service/src/main/java/com/example/order_service/OrderServiceApplication.java

Service discovery and inter-service boundary

discovery-server is the registration/discovery infrastructure. Cross-service dependencies are represented by named client interfaces and Feign configuration, rather than direct repository access. Each service has its own application.yaml, which is the central runtime configuration boundary.

• discovery-server/src/main/resources/application.yaml

• cart-service/src/main/java/com/example/cart_service/client/ProductServiceClient.java

• order-service/src/main/java/com/example/order_service/config/AppConfig.java

Catalog and inventory domains

Category and product services own catalog records; inventory owns stock records and stock-status semantics. Product, payment, and notification services each declare clients for category and inventory, meaning their workflows depend on remote catalog/stock lookups rather than shared models.

• category-service/src/main/java/com/example/category_service/service/CategoryService.java

• product-service/src/main/java/com/example/product_service/service/ProductService.java

• inventory-service/src/main/java/com/example/inventory_service/service/InventoryService.java

Cart workflow

Cart service persists carts and cart items locally, while validating/enriching cart operations through product and inventory clients. Its controller is the cart HTTP entry point; the service coordinates local state and remote dependencies.

• cart-service/src/main/java/com/example/cart_service/controller/CartController.java

• cart-service/src/main/java/com/example/cart_service/service/CartService.java

• cart-service/src/main/java/com/example/cart_service/model/CartItem.java

Order orchestration

Order service is the primary transaction-like coordinator. It owns orders/order items and has outbound dependencies on cart, inventory, and notification services. The expected control path is request → order validation/creation → cart and stock interactions → notification invocation, with remote failures surfaced as service-communication or stock exceptions.

• order-service/src/main/java/com/example/order_service/service/OrderService.java

• order-service/src/main/java/com/example/order_service/client/CartServiceClient.java

• order-service/src/main/java/com/example/order_service/client/NotificationServiceClient.java

Payment and notifications

Payment owns payment and payment-detail persistence, with payment method/status/currency domain enums. Notification owns notification persistence and remotely references category and inventory. Neither directory shows a direct client connection to order service; they are independently callable services, with order explicitly calling notification.

• payment-service/src/main/java/com/example/payment_service/service/PaymentService.java

• payment-service/src/main/java/com/example/payment_service/model/PaymentDetails.java

• notification-service/src/main/java/com/example/notification_service/service/NotificationService.java

Identity, persistence, and error contracts

User service independently owns user lifecycle and address-related request/response contracts. Across services, controllers accept dedicated DTOs, services map to local JPA-style entities/repositories, and global handlers translate domain and remote-call failures into shared API-response shapes. Data is service-owned: there are no shared repository modules.

• user-service/src/main/java/com/example/user_service/controller/UserController.java

• user-service/src/main/java/com/example/user_service/service/UserService.java

• product-service/src/main/java/com/example/product_service/exception/GlobalExceptionHandler.java