How to query the M: n relationship with JPA2?

I have an object (blogpost), which contains a collection of M: n elements (tags)

How to query an object (blogpost), in which the label of at least one object matches the element in a group of labels (defined by the user) and JPA2 (hibernate)

findBlogPostWithAtLeastOneMatchingTag(Collection<Tag> tags){ ???? }

My main problem is that I actually need to compare two tag sets: – the tag set of blogpost. – My search collection

I try to select P from post P, where p.tags is in (: Tags), but it doesn't work because my post entity has only one tag

What should I do?

My blogpost entity looks like this It has several labels

@Entity
public class BlogPost{

    /** The tags. */
    @ManyToMany()
    @NotNull
    private Set<Tag> tags;

    @NotBlank
    private String content;

    ...
}

The solution cannot be jpql or JPA criteria (not hibernate criteria)

Solution

If you like JPA criteria, this is your solution:

List<Integer> mytagsIds = new ArrayList<Integer> ();
mytagsIds.add(1);
mytagsIds.add(2);

CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery<BlogPost> cq = cb.createQuery(BlogPost.class);
Root<BlogPost> blogPost = cq.from(BlogPost.class);
SetJoin<BlogPost,Tag> tags = blogPost.join(BlogPost_.tags);
Predicate predicate = tags.get(Tag_.id).in(mytagsIds);
cq.distinct(true);
cq.where(predicate);
TypedQuery<BlogPost> tq = em.createQuery(cq);
return tq.getResultList();

This solution uses the canonical metamodel class blogpost that should be generated by the JPA implementation_ And tag_