MongoDB/Morphia大小查詢操作失敗？

Question

我使用MondoDB和Morphia 0.105圖層。

我User類是：

@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>(); 

和我的測試類是：

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); 
    } 

} 

我得到這個意外的結果：

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' 

如果我取消線//u.getRights().add(Rights.ADMIN);，增加了用戶權限，查詢ds.find(User.class).filter("rights size", 1).get()返回更正等結果（即使顯示警告，但這是一個誤報，因爲在我看來，將大小運算符的結果與整數進行比較是正確的）！

我該如何查詢空rights list/set字段的用戶？

感謝

Answer 1

試試這個：

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