ebron-sasack/buynow-user-service

Purpose and Runtime

BuyNow User Service is a Java 21 Spring Boot microservice for customer profiles and multiple user addresses. Its executable entry point is src/main/java/com/buynow/user_service/UserServiceApplication.java; runtime settings, including relational-database connectivity, belong in src/main/resources/application.properties. Maven build/dependency management is defined by pom.xml.

HTTP/API Boundary

Spring MVC controllers expose the user and address REST boundary:

• src/main/java/com/buynow/user_service/controller/UserController.java

• src/main/java/com/buynow/user_service/controller/AddressController.java

The documented flow covers retrieval and updates for /api/v1/users/{id}, plus creation and listing of /api/v1/users/{id}/addresses. src/main/java/com/buynow/user_service/configuration/WebConfig.java is the web-layer configuration boundary.

Request and Response Contracts

Controllers accept purpose-specific mutation DTOs rather than persistence entities:

• src/main/java/com/buynow/user_service/dto/request/CreateUserRequest.java

• src/main/java/com/buynow/user_service/dto/request/UpdateUserRequest.java

• src/main/java/com/buynow/user_service/dto/request/CreateAddressRequest.java

Responses are projected through src/main/java/com/buynow/user_service/dto/response/UserResponse.java and src/main/java/com/buynow/user_service/dto/response/AddressResponse.java, separating public API representation from JPA storage models.

Domain Model

The core persistent aggregate is user profile data in src/main/java/com/buynow/user_service/entity/User.java, with associated addresses in src/main/java/com/buynow/user_service/entity/Address.java. Address classification is represented by src/main/java/com/buynow/user_service/enums/AddressType.java. The tree also contains src/main/java/com/buynow/user_service/entity/SellerApplication.java and its lifecycle enum src/main/java/com/buynow/user_service/enums/ApplicationStatus.java, indicating a seller-application domain model, though no corresponding controller/service/repository is present.

Application-Service Layer

Business orchestration is defined through service interfaces and implementations:

• src/main/java/com/buynow/user_service/service/UserService.java

• src/main/java/com/buynow/user_service/service/implementation/UserServiceImpl.java

• src/main/java/com/buynow/user_service/service/implementation/AddressServiceImpl.java

Primary control flow is controller → service → repository → relational database. Services own user existence checks, profile/address updates, relationship handling, and conversion between request/entity/response shapes.

Persistence Boundary

Spring Data JPA repositories isolate database access:

• src/main/java/com/buynow/user_service/repository/UserRepository.java

• src/main/java/com/buynow/user_service/repository/AddressRepository.java

The service is designed for MySQL or PostgreSQL, selected/configured externally through application properties. Entity classes are the JPA mapping boundary; clients do not directly receive them.

Error and API Envelope Handling

Domain and validation failures are represented by typed exceptions such as src/main/java/com/buynow/user_service/exception/ResourceNotFoundException.java and src/main/java/com/buynow/user_service/exception/AlreadyExistsException.java. src/main/java/com/buynow/user_service/exception/GlobalExceptionHandler.java centralizes their HTTP translation. Shared success/error payload types reside in src/main/java/com/buynow/user_service/payload/ApiResponse.java and src/main/java/com/buynow/user_service/payload/ErrorResponse.java.