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
