Q Class Usage (Specification Support)

Overview

ElastiCORE automatically generates Q classes based on entity definitions. Q classes are type-safe builders that allow you to define JPA Specification conditions based on fields.

Basic Usage

Specification<Entity> spec = Q.Entity.name(Op.LIKE, "test")
    .and(Q.Entity.createdAt(Op.GTE, startDate, true));

Supported Operators (Op)

Operator	Description	Example
Op.EQUAL	Exact match	Q.User.status(Op.EQUAL, "ACTIVE")
Op.LIKE	Partial match	Q.User.name(Op.LIKE, "John")
Op.IN	Multiple values	Q.User.role(Op.IN, roleList)
Op.GT	Greater than	Q.User.age(Op.GT, 20)
Op.GTE	Greater than or equal	Q.User.age(Op.GTE, 18)
Op.LT	Less than	Q.User.age(Op.LT, 65)
Op.LTE	Less than or equal	Q.User.age(Op.LTE, 60)

Condition Combination

AND Combination

Specification<User> spec = Q.User.name(Op.LIKE, "John Doe")
    .and(Q.User.status(Op.EQUAL, "ACTIVE"))
    .and(Q.User.age(Op.GTE, 20));

OR Combination

Specification<User> spec = Q.User.name(Op.LIKE, "John")
    .or(Q.User.email(Op.LIKE, "john"));

Practical Usage Example

@Service
public class UserService {

    @Autowired
    private UserRepository userRepository;

    public Page<User> searchUsers(UserSearchDTO searchDTO) {
        Specification<User> spec = Specification.where(null);
        
        if (searchDTO.getName() != null) {
            spec = spec.and(Q.User.name(Op.LIKE, searchDTO.getName()));
        }
        if (searchDTO.getStatus() != null) {
            spec = spec.and(Q.User.status(Op.EQUAL, searchDTO.getStatus()));
        }
        
        return userRepository.findAll(spec, searchDTO.getPageable());
    }
}

Q Class Generation Location

Q classes are generated according to the namespace settings in env.yml:

q: io.domain.q

Generation command:

./gradlew elcore