architecture

name	architecture
description	Hexagonal architecture structure and rules for this project. Use this when creating new files or features to place them in the correct layer.

## Dependency Direction

adapter/in → port/in → service → port/out → adapter/out

- `adapter/in` depends on `port/in`
- `service` implements `port/in`, depends on `port/out`
- `adapter/out` implements `port/out`
- `domain` has no dependencies on any layer

## Layer Rules

### domain/
- Pure Kotlin class. No JPA annotations, no Spring annotations.
- Must not know about JPA, Redis, or any infrastructure.

### application/port/in/
- UseCase interface. Defines what the application can do.
- Called by `adapter/in`.

### application/port/out/
- Persistence port interface. Defines what the application needs from outside.
- Called by `service`. Implemented by `adapter/out`.

### application/service/
- Implements UseCase. Contains business logic.
- Only knows `port/out` interface — never knows JPA directly.
- `@Transactional` goes here.

### adapter/in/
- GraphQL controller (`@MutationMapping`, `@QueryMapping`).
- Calls UseCase only. No business logic here.

### adapter/out/persistence/
- Implements persistence port.
- Knows JPA. Handles `{Domain}JpaEntity` ↔ `{Domain}` conversion via extension functions.
```kotlin
fun {Domain}JpaEntity.toDomain() = {Domain}(...)
fun {Domain}.toEntity() = {Domain}JpaEntity(...)

global/

• Cross-cutting concerns: config, security, common exceptions.

Naming Rules

Layer	Naming
UseCase	Fetch{Domain}UseCase, Append{Domain}UseCase
PersistencePort	{Domain}PersistencePort
Service	Fetch{Domain}Service, Modify{Domain}Service
WebAdapter	{Domain}WebAdapter
PersistenceAdapter	{Domain}PersistenceAdapter
JpaEntity	{Domain}JpaEntity
JpaRepository	{Domain}JpaRepository