Java – how to filter by entity class attribute in Hibernate

I use hibernate in Java to map classes to database tables I have a personnel list. Each item has many pets and each pet has many toys

I hope to filter these contents in my Dao according to the attributes of toys; For example, find all pets with red toys as list < person > How do I filter?

Personnel type:

@Entity
public class Person {

    ...
    @OneToMany(mappedBy = "person")
    private List<Pet> pets;

    ...
}

Pets:

@Entity
public class Pet {

    ...
    @OneToMany(mappedBy = "pet")
    private List<Toy> toys;

    ...
}

Toys:

@Entity
public class Toy {

    ...
    private String colour;

    ...
}

Solution

In this case, I'm not sure you mean 'filter', but you can always use HQL

select p from Person p 
              inner join p.pets as pets
              inner join pets.toys as toys
              where p.pets.size() > 0 
              and toys.color = 'red'

Maybe the condition 'p.pets Size() > 0 'is redundant here due to internal connection