Replacing deprecated QuerydslJpaRepository with QuerydslJpaPredicateExecutor fails

Question

I needed some custom QueryDSL enabled query methods and followed this SO answer.

That worked great, but after upgrading to Spring Boot 2.1 (which upgrades Spring Dat

Answer 1

With Spring Boot 2.1.1 the following solution may help you. The key is to extend JpaRepositoryFactory and override the method getRepositoryFragments(RepositoryMetadata metadata). In this method you can provide base (or more specific fragment) implementations for any custom repository which should be taken for every extending repository.

Let me show you an example:

QueryableReadRepository:

@NoRepositoryBean
public interface QueryableReadRepository<T> extends Repository<T, String> {

  List<T> findAll(Predicate predicate);

  List<T> findAll(Sort sort);

  List<T> findAll(Predicate predicate, Sort sort);

  List<T> findAll(OrderSpecifier<?>... orders);

  List<T> findAll(Predicate predicate, OrderSpecifier<?>... orders);

  Page<T> findAll(Pageable page);

  Page<T> findAll(Predicate predicate, Pageable page);

  Optional<T> findOne(Predicate predicate);

  boolean exists(Predicate predicate);
}

The following interface combines different repositories.

DataRepository:

@NoRepositoryBean
public interface DataRepository<T>
    extends CrudRepository<T, String>, QueryableReadRepository<T> {
}

Now your specific domain repos can extend from DataRepository:

@Repository
public interface UserRepository extends DataRepository<UserEntity> {

}

QueryableReadRepositoryImpl:

@Transactional
public class QueryableReadRepositoryImpl<T> extends QuerydslJpaPredicateExecutor<T>
    implements QueryableReadRepository<T> {

  private static final EntityPathResolver resolver = SimpleEntityPathResolver.INSTANCE;

  private final EntityPath<T> path;
  private final PathBuilder<T> builder;
  private final Querydsl querydsl;

  public QueryableReadRepositoryImpl(JpaEntityInformation<T, ?> entityInformation,
      EntityManager entityManager) {
    super(entityInformation, entityManager, resolver, null);
    this.path = resolver.createPath(entityInformation.getJavaType());
    this.builder = new PathBuilder<T>(path.getType(), path.getMetadata());
    this.querydsl = new Querydsl(entityManager, builder);
  }

  @Override
  public Optional<T> findOne(Predicate predicate) {
    return super.findOne(predicate);
  }

  @Override
  public List<T> findAll(OrderSpecifier<?>... orders) {
    return super.findAll(orders);
  }

  @Override
  public List<T> findAll(Predicate predicate, Sort sort) {
    return executeSorted(createQuery(predicate).select(path), sort);
  }

  @Override
  public Page<T> findAll(Predicate predicate, Pageable pageable) {
    return super.findAll(predicate, pageable);
  }

  @Override
  public List<T> findAll(Predicate predicate) {
    return super.findAll(predicate);
  }

  public List<T> findAll(Sort sort) {
    return executeSorted(createQuery().select(path), sort);
  }

  @Override
  public Page<T> findAll(Pageable pageable) {
    final JPQLQuery<?> countQuery = createCountQuery();
    JPQLQuery<T> query = querydsl.applyPagination(pageable, createQuery().select(path));

    return PageableExecutionUtils.getPage(
        query.distinct().fetch(), 
        pageable,
        countQuery::fetchCount);
  }

  private List<T> executeSorted(JPQLQuery<T> query, Sort sort) {
    return querydsl.applySorting(sort, query).distinct().fetch();
  }
}

CustomRepositoryFactoryBean:

public class CustomRepositoryFactoryBean<T extends Repository<S, I>, S, I>
    extends JpaRepositoryFactoryBean<T, S, I> {

  public CustomRepositoryFactoryBean(Class<? extends T> repositoryInterface) {
    super(repositoryInterface);
  }

  protected RepositoryFactorySupport createRepositoryFactory(EntityManager entityManager) {
    return new CustomRepositoryFactory(entityManager);
  }

CustomRepositoryFactory:

public class CustomRepositoryFactory extends JpaRepositoryFactory {

  private final EntityManager entityManager;

  public CustomRepositoryFactory(EntityManager entityManager) {
    super(entityManager);
    this.entityManager = entityManager;
  }

  @Override
  protected RepositoryFragments getRepositoryFragments(RepositoryMetadata metadata) {
    RepositoryFragments fragments = super.getRepositoryFragments(metadata);

    if (QueryableReadRepository.class.isAssignableFrom(
        metadata.getRepositoryInterface())) {

      JpaEntityInformation<?, Serializable> entityInformation = 
          getEntityInformation(metadata.getDomainType());

      Object queryableFragment = getTargetRepositoryViaReflection(
          QueryableReadRepositoryImpl.class, entityInformation, entityManager);

      fragments = fragments.append(RepositoryFragment.implemented(queryableFragment));
    }

    return fragments;
  }

Main class:

@EnableJpaRepositories(repositoryFactoryBeanClass = CustomRepositoryFactoryBean.class)
public class App {
}

This has the advantage that you provide only one (fragment) implementation for a custom repo. The base repository implementation is still Spring's default implementation. The example provided a new repo but you can probably also just override the default implementation of QuerydslPredicateExecutor in CustomRepositoryFactory

Answer 2

This test case has a cleaner version of running queries using querydsl

https://github.com/spring-projects/spring-data-jpa/blob/master/src/test/java/org/springframework/data/jpa/repository/support/QuerydslJpaPredicateExecutorUnitTests.java

        JpaEntityInformation<User, Integer> information = new JpaMetamodelEntityInformation<>(User.class,
                em.getMetamodel());

        SimpleJpaRepository<User, Integer> repository = new SimpleJpaRepository<>(information, em);
        dave = repository.save(new User("Dave", "Matthews", "dave@matthews.com"));
        carter = repository.save(new User("Carter", "Beauford", "carter@beauford.com"));
        oliver = repository.save(new User("Oliver", "matthews", "oliver@matthews.com"));
        adminRole = em.merge(new Role("admin"));

        this.predicateExecutor = new QuerydslJpaPredicateExecutor<>(information, em, SimpleEntityPathResolver.INSTANCE, null);
        BooleanExpression isCalledDave = user.firstname.eq("Dave");
        BooleanExpression isBeauford = user.lastname.eq("Beauford");

        List<User> result = predicateExecutor.findAll(isCalledDave.or(isBeauford));
        assertThat(result).containsExactlyInAnyOrder(carter, dave);

Answer 3

In Spring Data JPA 2.1.6 the constructor of QuerydslJpaPredicateExecutor has changed. I present here an alternative approach using a wrapper to https://stackoverflow.com/a/53960209/3351474. This makes the solution independent from the internals of Spring Data JPA. Three classes have to be implemented.

As an example I take here a customized Querydsl implementation using always the creationDate of an entity as sort criteria if nothing is passed. I assume in this example that this column exists in some @MappedSuperClass for all entities. Use generated static metadata in real life instead the hard coded string "creationDate".

As first the wrapped delegating all CustomQuerydslJpaRepositoryIml delegating all methods to the QuerydslJpaPredicateExecutor:

/**
 * Customized Querydsl JPA repository to apply custom filtering and sorting logic.
 *
 */
public class CustomQuerydslJpaRepositoryIml<T> implements QuerydslPredicateExecutor<T> {

    private final QuerydslJpaPredicateExecutor querydslPredicateExecutor;

    public CustomQuerydslJpaRepositoryIml(QuerydslJpaPredicateExecutor querydslPredicateExecutor) {
        this.querydslPredicateExecutor = querydslPredicateExecutor;
    }

    private Sort applyDefaultOrder(Sort sort) {
        if (sort.isUnsorted()) {
            return Sort.by("creationDate").ascending();
        }
        return sort;
    }

    private Pageable applyDefaultOrder(Pageable pageable) {
        if (pageable.getSort().isUnsorted()) {
            Sort defaultSort = Sort.by(AuditableEntity_.CREATION_DATE).ascending();
            pageable = PageRequest.of(pageable.getPageNumber(), pageable.getPageSize(), defaultSort);
        }
        return pageable;
    }

    @Override
    public Optional<T> findOne(Predicate predicate) {
        return querydslPredicateExecutor.findOne(predicate);
    }

    @Override
    public List<T> findAll(Predicate predicate) {
        return querydslPredicateExecutor.findAll(predicate);
    }

    @Override
    public List<T> findAll(Predicate predicate, Sort sort) {
        return querydslPredicateExecutor.findAll(predicate, applyDefaultOrder(sort));
    }

    @Override
    public List<T> findAll(Predicate predicate, OrderSpecifier<?>... orders) {
        return querydslPredicateExecutor.findAll(predicate, orders);
    }

    @Override
    public List<T> findAll(OrderSpecifier<?>... orders) {
        return querydslPredicateExecutor.findAll(orders);
    }

    @Override
    public Page<T> findAll(Predicate predicate, Pageable pageable) {
        return querydslPredicateExecutor.findAll(predicate, applyDefaultOrder(pageable));
    }

    @Override
    public long count(Predicate predicate) {
        return querydslPredicateExecutor.count(predicate);
    }

    @Override
    public boolean exists(Predicate predicate) {
        return querydslPredicateExecutor.exists(predicate);
    }
}

Next the CustomJpaRepositoryFactory doing the magic and providing the Querydsl wrapper class instead of the default one. The default one is passed as parameter and wrapped.

/**
 * Custom JpaRepositoryFactory allowing to support a custom QuerydslJpaRepository.
 *
 */
public class CustomJpaRepositoryFactory extends JpaRepositoryFactory {

    /**
     * Creates a new {@link JpaRepositoryFactory}.
     *
     * @param entityManager must not be {@literal null}
     */
    public CustomJpaRepositoryFactory(EntityManager entityManager) {
        super(entityManager);
    }

    @Override
    protected RepositoryComposition.RepositoryFragments getRepositoryFragments(RepositoryMetadata metadata) {
        final RepositoryComposition.RepositoryFragments[] modifiedFragments = {RepositoryComposition.RepositoryFragments.empty()};
        RepositoryComposition.RepositoryFragments fragments = super.getRepositoryFragments(metadata);
        // because QuerydslJpaPredicateExecutor is using som internal classes only a wrapper can be used.
        fragments.stream().forEach(
                f -> {
                    if (f.getImplementation().isPresent() &&
                            QuerydslJpaPredicateExecutor.class.isAssignableFrom(f.getImplementation().get().getClass())) {
                        modifiedFragments[0] = modifiedFragments[0].append(RepositoryFragment.implemented(
                                new CustomQuerydslJpaRepositoryIml((QuerydslJpaPredicateExecutor) f.getImplementation().get())));
                    } else {
                        modifiedFragments[0].append(f);
                    }
                }
        );
        return modifiedFragments[0];
    }
}

Finally the CustomJpaRepositoryFactoryBean. This must be registered with the Spring Boot application, to make Spring aware where to get the repository implementations from, e.g. with:

@SpringBootApplication
@EnableJpaRepositories(basePackages = "your.package",
        repositoryFactoryBeanClass = CustomJpaRepositoryFactoryBean.class)
...

Here now the class:

public class CustomJpaRepositoryFactoryBean<T extends Repository<S, I>, S, I> extends JpaRepositoryFactoryBean<T, S, I> {

    /**
     * Creates a new {@link JpaRepositoryFactoryBean} for the given repository interface.
     *
     * @param repositoryInterface must not be {@literal null}.
     */
    public CustomJpaRepositoryFactoryBean(Class<? extends T> repositoryInterface) {
        super(repositoryInterface);
    }

    protected RepositoryFactorySupport createRepositoryFactory(EntityManager entityManager) {
        return new CustomJpaRepositoryFactory(entityManager);
    }
}