MongoDB/Morphia size query operator malfunction?

Question

i'm using MondoDB with Morphia 0.105 layer.

My User class is:

@Entity
public class User {

@Id
private ObjectId id = null;

private String userId = null;
private String fullName = null;
@Embedded
private UserType userType = null;
@Embedded
private Set<Rights> rights = new HashSet<Rights>();

and my test class is:

public class Test {

    public static void main(String[] args) throws UnknownHostException {
        Morphia m = new Morphia();
        Datastore ds = m.createDatastore(new MongoClient("localhost"), "test");
        m.map(User.class);


        User u = new User();
        u.setFullName("User Name");
        u.setUserId("USERID");
        //u.getRights().add(Rights.ADMIN); //NO rights added VS ONE right added

        ds.save(u);
        u = ds.find(User.class).filter("rights size", 0).get();
        System.out.println(u);
        System.out.println(u != null);
    }

}

I got this unexpected result:

The type(s) for the query/update may be inconsistent; using an instance of type 'java.lang.Integer' for the field 'org.vts.sis2.entities.User.rights' which is declared as 'java.util.Set'

If i uncomment line //u.getRights().add(Rights.ADMIN); that adds to user a right, the query ds.find(User.class).filter("rights size", 1).get() returns the correct result (even if the warning is displayed, but it's a false positive since in my opinion it's correct to compare a result of size operator to an integer)!

What should i do to query users with empty rights list/set field?

Thanks

Answer 1

Try this:

ds.find(User.class).field("rights").sizeEq(0).get()