Code Conventions Skill

Java / Backend Conventions

User Identity Type

User identity is always String throughout the codebase. This covers:

• Authentication and authorization
• API parameters and responses
• Permission checks
• Audit logs
• Resource owner, creator, reviewer, actor, submittedBy fields

Never introduce int, long, or bigint as user identifiers. The platform needs to support external SSO/OIDC/SCIM identity sources whose UIDs are typically stable strings.

Exception Handling

• Use LocalizedDomainException for user-facing error messages (supports i18n)
• Use DomainBadRequestException for invalid client input
• Use DomainNotFoundException for missing resources
• Use DomainForbiddenException for authorization failures
• Exception classes live in skillhub-domain/shared/exception/

Domain Services

• Return domain objects, not DTOs
• Contain business rules and state transitions
• Use domain events for cross-cutting side effects (publishing, notifications)
• Located in domain/{submodule}/service/

Controllers

• Transport only: extract auth context, bind request params, wrap responses
• No business logic in controllers
• Located in com.iflytek.skillhub.controller/

Query Repositories

• Handle read-model joins and presentation projection
• Return DTOs or presentation models
• Located in com.iflytek.skillhub.repository/
• Named like *QueryRepository (e.g., GovernanceQueryRepository, MySkillQueryRepository)

App Services

• Workflow orchestration: coordinate domain services and query repositories
• Should express "what this endpoint does", not "how it assembles DTOs"
• Located in com.iflytek.skillhub.service/

Logging

• Use SLF4J with structured logging
• Use MDC for request tracing
• Log at appropriate levels: INFO for business events, DEBUG for troubleshooting, ERROR for failures

TypeScript / Frontend Conventions

Type Safety

• Strict TypeScript mode. No any types.
• Use generated OpenAPI types from web/src/api/generated/schema.d.ts for all API interactions.
• Additional types in web/src/types/

Data Fetching

• Always use TanStack Query (@tanstack/react-query) for server state
• Never use useEffect for data fetching
• Use openapi-fetch client for type-safe API calls

Component Composition

• Radix UI primitives: @radix-ui/react-dropdown-menu, @radix-ui/react-select
• class-variance-authority (cva) for component variants
• clsx + tailwind-merge for class merging
• cn() utility: web/src/shared/lib/utils.ts
• shadcn/ui is NOT used as a library

State Management

• TanStack Query for server state (API data, caching, invalidation)
• Zustand for local/UI state (theme, sidebar, modals, form state)

Feature-Sliced Design

Place code at the lowest appropriate layer. Do not put page-level logic in shared.

Styling

• Tailwind CSS for all styling
• Follow existing component patterns
• Use cn() for conditional class merging

Internationalization

• Use i18next + react-i18next
• All user-facing text must be translatable
• Translation keys in web/src/i18n/

Testing Philosophy

Backend

• JUnit 5 + Mockito + AssertJ
• Use Spring Boot test slices where possible (@WebMvcTest, @DataJpaTest)
• Test behaviors, not implementations
• Use make test-backend-app (includes -am for dependent modules)
• Never run ./mvnw -pl skillhub-app clean test directly — stale Maven cache causes misleading errors

Frontend

• Vitest for unit tests
• Playwright for E2E tests
• Test component behavior and user interactions

Common Pitfalls

• Maven multi-module: Always use -am flag or Makefile targets to include dependent modules
• OpenAPI types: Must regenerate and commit after API contract changes
• String identity: Never use numeric types for user identifiers
• Controller business logic: Move to domain service or app service
• Complex read-models in app service: Extract to query repository