name: app-usecase-generator description: "Generates app-layer use cases (Command/Handler/Assembler/DTO) following package-info and transaction rules (spring-tx only)."

App Use Case Generator

Follow .codex/skills/GENERATOR_SKILL_STRUCTURE.md.

Templates: See references/templates.md.

Use For

• app/{{bcName}}/command/** and app/{{bcName}}/query/**

Inputs Required

• Business use-case name (verb + object)
• Command/Query DTO fields
• Required domain ports (repositories/gateways)
• Transaction boundary requirement (yes/no)

Outputs

• Command side (typical):
  • .../app/{{bcName}}/command/dto/<XxxCommand>.java
  • .../app/{{bcName}}/command/handler/<XxxCommandHandler>.java
  • .../app/{{bcName}}/command/assembler/<XxxAssembler>.java (optional)
• Query side (typical):
  • .../app/{{bcName}}/query/dto/<XxxQuery>.java
  • .../app/{{bcName}}/query/service/<XxxQueryService>.java
• Tests:
  • .../app/.../<Xxx>Test.java (mock ports)

Naming & Packaging

• Follow existing package-info.java packages:
  • {{basePackage}}.app.{{bcName}}.command.*
  • {{basePackage}}.app.{{bcName}}.query.*
• Keep adapter DTOs out of app packages.

Implementation Rules

• App layer can use org.springframework.transaction.annotation.Transactional when needed.
• Do not introduce other Spring stereotypes (@Service/@Component) unless project conventions explicitly allow.
• Separate command DTOs, assemblers, and handlers as per existing structure.

Reference Implementations

• {{appModuleDir}}/src/main/java/{{basePackagePath}}/app/{{bcName}}/command/package-info.java
• {{appModuleDir}}/src/main/java/{{basePackagePath}}/app/common/workflow/service/WorkflowStartService.java

Tests

• Unit tests validate:
  • orchestration order
  • port calls
  • error mapping (retryable vs non-retryable where applicable)

Pitfalls

• Putting persistence types (PO/Mapper) into app DTOs.
• Using Spring components in app beyond spring-tx.

Output checklist

• Correct package per package-info.java
• Transaction boundary explicit when required
• Unit tests for orchestration logic (mock ports)