Implement Sztab Domain Queries using JpaSpecificationExecutor

Goal:
Expose flexible REST API search capabilities for core domain entities using Spring Data JPA Specifications.

Estimated Time: 6–8 hours

Task Breakdown

1. Enable Specification Support

•  Ensure all repositories extend JpaSpecificationExecutor<T>
•  Add custom specification builders for:
  • User
  • Project
  • Issue

2. Define Filter Criteria

•  For Issue: support filtering by
  • status
  • priority
  • severity
  • assignee
  • project
•  For Project: support filtering by
  • startDate, endDate
  • owner
•  For User: support filtering by
  • username, email, roles

3. Create REST Query Endpoints

•  Add query parameters to existing GET /issues, GET /projects, GET /users
•  Map query params to specifications dynamically
•  Add pagination and sorting support

4. Add Integration Tests

•  Use @SpringBootTest or @DataJpaTest to test query behavior
•  Cover positive + negative + edge case filters
•  Target at least 80% test coverage on query logic

5. Document Query API

•  Update OpenAPI (Springdoc) or README with sample query formats
  • e.g. /issues?status=OPEN&priority=HIGH

Output Artifacts

• Dynamic REST API query support for User, Project, and Issue
• Well-tested JpaSpecification implementations
• Updated API documentation

Notes:
Code should remain consistent with service-layer abstraction (i.e., use service methods rather than wiring specs into controllers directly).