Extend findAll with custom filters

Question

I am trying to extend findAll from my JPA repository to make custom filters.

I did some research and found some ideas of use with Predicates and the like but did not identify something that worked in a practical way.

I wonder if someone has ever been through something like this or have some idea of how to do it without I need to create various forms of research within my Repository.

Answer 1

One of the ways to modify the default behavior of a Spring Data JPA method is to create another repository base implementation. In the documentation is shown as adds custom behavior to the repository.

The steps to be followed are more or less these:

1. create a custom interface for your repositories, and can extend the JpaRepository even, something like that:

@NoRepositoryBean
public interface CustomGenericRepository<E extends CustomAbstractEntity, PK extends Serializable> extends
        JpaRepository<E, PK>, JpaSpecificationExecutor<E> { }

We will extend as well JpaSpecificationExecutor, why our custom repository will use Specifications and she supports this.

2. the second step is to implement this interface that we have just defined. Below is an example that changes the behavior of findAll, using a Specification which will consider in the query only the records not deleted logically, something like this:

public class CustomGenericRepositoryImpl<E extends CustomAbstractEntity, PK extends Serializable> extends
        SimpleJpaRepository<E, PK> implements CustomGenericRepository<E, PK> {

    private final EntityManager entityManager;

    public CustomGenericRepositoryImpl(final Class<T> domainClass, final EntityManager entityManager) {
        super(domainClass, entityManager);
        this.entityManager = entityManager;
    }

    @Override
    public List<E> findAll() {
        return super.findAll(this.isRemoved());
    }

    private Specification<E> isRemoved() {
        return new Specification<E>() {

            @Override
            public Predicate toPredicate(final Root<E> root, final CriteriaQuery<?> query, final CriteriaBuilder cb) {
                return cb.isFalse(root.<Boolean> get("deleted"));
            }

        };

    }

}

3. as we have a different implementation that we will use in our repositories, we need to create a way to instruct container spring as it will create the instances for the repositories. Then, we will create a Factory bean also customized and that also extends from one that is JPA, the JpaRepositoryFactoryBean:

public class CustomGenericRepositoryFactoryBean<T extends JpaRepository<S, ID>, S, ID extends Serializable> extends
        JpaRepositoryFactoryBean<T, S, ID> {

    @Override
    protected RepositoryFactorySupport createRepositoryFactory(final EntityManager entityManager) {
        return new RepositoryFactory(entityManager);
    }

    private static class RepositoryFactory<T, I extends Serializable> extends JpaRepositoryFactory {

        public RepositoryFactory(final EntityManager entityManager) {
            super(entityManager);
        }

        protected Object getTargetRepository(final RepositoryMetadata metadata) {
            return new CustomGenericRepositoryImpl<T, I>((Class<T>) metadata.getDomainClass(), em);
        }

        @Override
        protected Class<?> getRepositoryBaseClass(final RepositoryMetadata metadata) {
            return CustomGenericRepositoryImpl.class;
        }

    }

}

4. Finally, we need to talk to the spring date what is the factory-class to create our repositories. Using XML you can use it like this:

<jpa:repositories base-package="com.brunocesar.custom.repository,com.brunocesar.custom.repository.support"
    factory-class="com.brunocesar.custom.repository.support.factory.CustomGenericRepositoryFactoryBean"
    transaction-manager-ref="transactionManagerCustom" entity-manager-factory-ref="entityManagerFactoryCustom" />

Using Java, considering a class only for configuration of repositories, just configure the attribute factoryClass of @EnableJpaRepositories, something like that:

@EnableJpaRepositories(factoryClass = "com.brunocesar.custom.repository.support.factory.CustomGenericRepositoryFactoryBean")
public class JPARepositoryConfig {

    // o resto da configuração continua a mesma =)

}

To use, simply extend your repository’s custom interface, CustomGenericRepository, something like that:

@Repository
public interface PessoaRepository extends CustomGenericRepository<Pessoa, Long> {

}

Answer 2

Implements Jparepository that Voce can customize your queries according to the attributes of your example object below :

public interface Empregado extends JpaRepository<Empregado , Integer> {
   //Atributo Endereco dentro de Empregado ele já implementa pra vc tudo!
   List<Empregado> findByEndereco(Endereco endereco );
}