Spring data querying with complex object marked by @Param

Question

I have an entity with aggregation information that I am going to receive from database:

class BookStats {
    String author
    String title
    Integer count
}

My question is could I use some complex object in Repository to filter statistic information. Something like that:

 @Query(value = "SELECT new com.test.book.BookStats(b.author, b.title, count(b)) from Book b where b.title = :filter.title and b.author= :filter.author")
    List<BookStats> calculateBookStats (@Param("filter") Filter filter)

Answer 1

Spring Data JPA allows to use SpEL :

@Query(value = "SELECT new com.test.book.BookStats(b.author, b.title, count(b)) from Book b where b.title = :#{#filter.title} and b.author= :#{#filter.author}")
List<BookStats> calculateBookStats (@Param("filter") Filter filter)

More info here.