| name | paw-persistence-contracts-layer |
| description | Use when creating, changing, auditing, or reviewing PAW Forkd DAO interfaces and persistence-facing contracts in the persistence-contracts Maven module, including TP1 JDBC contracts and TP2 JPA-backed contract preservation. |
Paw Persistence Contracts Layer
Overview
Use this for persistence-contracts/, the module that lets services depend on DAO abstractions instead of JDBC implementations.
Read references/layer-rules.md before changing DAO contracts.
Workflow
- Inspect existing DAO interfaces in
persistence-contracts/src/main/java/ar/edu/itba/paw/persistence.
- Resolve stage: TP1 contracts must be implementable with JDBC SQL; TP2 contracts may be implemented by JPA but still must not leak ORM details.
- Define the contract from the service use case, not from a planned SQL/JPA implementation.
- Keep signatures free of
java.sql, JdbcTemplate, row mappers, EntityManager, JPQL strings, servlet/web types, and implementation classes.
- Prefer
PageRequest, sort/filter domain objects, and domain return types over loose offset/limit or raw maps.
- Add batch contracts when a web/service flow would otherwise call a DAO once per row.
- Update persistence implementation and tests in the same feature slice unless the user explicitly asks for contracts only.
Contract Rules
- One table should have one owning DAO for writes.
- DAO contracts can expose query intent but not SQL plumbing.
- Return empty lists/pages instead of
null.
- Use
Optional only if the existing DAO style supports it for that absence case.
- Keep names behavior-oriented:
findByRestaurantId, countFeedReviews, findReassignableForReservations.
Verification
- Contract-only compile:
mvn -pl persistence-contracts -am test.
- Contract plus JDBC implementation:
mvn -pl persistence -am test.
- Contract used by services/webapp:
mvn -pl webapp -am test or broader.
