I have an Entity look like this.
#Entity
class Property extends BaseEntity {
#Basic
private String name;
#Basic
private String value;
}
The basic intention is using this Entity as other Entities properties.
#Entity
class MyEntity extends BaseEntity {
#OneToMany
private List<Property> properties;
}
#Entity
class YourEntity extends BaseEntity {
#OneToMany
private List<Property> properties;
}
How can I do this? Do I have to define each owner's field in Property?
#Entity
class Property extends BaseEntity {
#Basic
private String name;
#Basic
private String value;
#ManyToOne(optional = true)
private MyEntity myEntity;
#ManyToOne(optional = true)
private YourEntity yourEntity;
#ManyToOne(optional = true)
private OtherEntity otherEntity;
}
Basically it is a good solution You represented here. There is the option to create a join table which will help you to keep the entity "cleaner" (and also could be used as a ManyToMany. In most of the cases I prefer to use the option You provided [simplicity is a gooooood thing :) ], but other colleagues got different view on this problem.
TL.DR: Your provided code is working and I personally prefer it. There are other ways but those are a bit slower etc.
Related
This is my entity with composite key:
#Entity
#Table(name = "course_ratings")
public class CourseRating {
#EmbeddedId
private CourseRatingKey id;
}
Where CourseRatingKey looks like this:
#Embeddable
public class CourseRatingKey implements Serializable {
#Column(name = "user_id")
private int userId;
#Column(name = "course_id")
private int courseId;
public CourseRatingKey() {
}
// getters, setters, equals(), hashCode()
}
And my JPA repository
#Repository
public interface CourseRatingRepository extends JpaRepository<CourseRating, CourseRatingKey> {
}
I am trying to build method that will return list of all CourseRating with given courseId property of CourseRatingKey. Below method doesn't work because JPA doesn't recognize it:
repository.findAllByIdCourseId(int id);
How can I build my method name to achieve my goal?
I have solved my problem by declaring this method in repository. I'm a bit confused as the other methods work without declaring.
#Repository
public interface CourseRatingRepository extends JpaRepository<CourseRating, CourseRatingKey> {
List<CourseRating> findAllByIdCourseId(Integer id);
}
I have a Spring Boot 1.3.5-RELEASE application which is using JPAto Relate my USERS to the ROLES with a Bi-directional ManyToMany relationship.
User
#Table(name = "Users")
#Entity
public class User extends BaseEntity {
#NotEmpty
#Column(unique = true)
private String username;
#NotEmpty
private String password;
#JoinColumn(name = "user_iid")
#OneToMany
private Set<UserRole> userRoles;
//getters and setters
UserRole (intermediary table)
#Table(uniqueConstraints = #UniqueConstraint(columnNames = { "user_iid", "role_iid" }))
#Entity
public class UserRole extends BaseEntity {
#RestResource(exported = false)
#ManyToOne
#NotNull
private User user;
#ManyToOne
private Role role;
//getters and setters
Role
#Entity
public class Role extends BaseEntity {
#NotEmpty
#Column(unique = true)
private String name;
#JoinColumn(name = "role_iid")
#OneToMany
private Set<UserRole> userRoles;
//getters and setters
BaseEntity is a class with Ids and Version generator.
Repository
#Repository
public interface Repository extends JpaRepository<Role, String> {
Role findByIid(#Param("iid") final String iid);
When I cURL a localhost:8080/roles/search/findByIid?iid=1 I get a StackOverflow. If the object does not exist, the application respond fine.
I already tried #JsonIgnore but does not work.
Thanks
I got the answer.
I updated the Spring Boot to 1.4.2-RELEASE (which is the last) and everything worked like a charm. I think with the update it updates JPA and Hibernate and make them handle better those ManyToMany relantionships.
I am trying to migrate a Seam 2 app to CDI and use PicketLink for security. After all the reading and researching, it seems like all the examples are having one to one mapping between PicketLink model and the backend entity. e.g. Account to AccountEntity, Partition to PartitionEntity. Since I already have entities in place representing identity model, I am stuck on trying to map them to PicketLink. Here is what I have:
#MappedSuperClass
public class ModelEntityBase implement Serializable {
#Id #Generated
Long id;
Date creationDate;
}
#Entity
public Account extends ModelEntityBase {
String username;
String passwordHash;
#OneToOne(mappedBy = "account")
Person person;
}
#Entity
public Person extends ModelEntityBase {
String name;
String email;
#OneToOne
#JoinColumn(name = "account_id")
Account account;
}
Two entities (plus a super class) representing a single identity model in PicketLink, e.g. stereo type User.
Based on this why IdentityType id is String not Long, I tried to add a new Entity in:
#Entity
#IdentityManaged(BaseIdentityType.class);
public class IdentityTypeEntity implement Serializble {
#Id #Identifier
private String id;
#OneToOne(optional = false, mappedBy = "identityType")
#OwnerReference
private Account account;
#IdentityClass
private String typeName;
#ManyToOne #OwnerReference
private PartitionEntity partition;
}
I've tried a few different ways with the annotation and model classes. But when using IdentityManager.add(myUserModel), I just can't get it to populate all the entities. Is this even possible?
Got help from Pedro (PicketLink Dev). Post the answer here to help others.
This is the model class I ended up using.
#IdentityStereotype(USER)
public class User extends AbstractAttributedType implements Account {
#AttributeProperty
private Account accountEntity;
#AttributeProperty
#StereotypeProperty(IDENTITY_USER_NAME)
#Unique
private String username;
#AttributeProperty
private boolean enabled;
#AttributeProperty
private Date createdDate;
#AttributeProperty
private Date expiryDate;
#AttributeProperty
private Partition partition;
// getter and setter omitted
}
And created a new entity to map to this model:
public class IdentityTypeEntity implements Serializable {
#Id
#Identifier
private String id;
#OneToOne(optional = false, mappedBy = "identityType",
cascade = CascadeType.ALL, fetch = FetchType.EAGER)
#AttributeValue
// #NotNull
private HAccount accountEntity;
#IdentityClass
private String typeName;
#ManyToOne
#OwnerReference
private PartitionEntity partition;
#AttributeValue
private String username;
#AttributeValue
// #Transient
private boolean enabled;
#AttributeValue
private Date createdDate;
#AttributeValue
private Date expiryDate;
}
PL can map property with #AttributeProperty to entity property with #AttributeValue. But it can only map to one entity. Therefore there is no way to map, say User and its properties over to Account and Person. But you can have the entity (in my case accountEntity) in the model. I also have to duplicate a few fields in the new IdentityTypeEntity and my existing Account entity (username, eanbled, createdDate) because PL requires these. Use a #PrePersist and similar to sync them.
Got GlassFish v3. I have an one-to-many entity. The problem is, that EclipseLink seems to ignore the fetch EAGER mode.
Here is my entities.
#Entity
public class Person implements Serializable
{
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String name;
#OneToMany(mappedBy = "person", fetch = FetchType.EAGER)
private List<Hobby> hobbies;
// getter and setter
}
A 1:n relationship
#Entity
public class Hobby
{
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String name;
#ManyToOne
#JoinColumn
private Person person;
// getter and setter
}
And the bean
#javax.ejb.Remote
public interface Testing
{
public void addTestData();
public List<Person> getTestData();
}
#javax.ejb.Stateless
public class TestingBean implements Testing
{
#javax.persistence.PersistenceContext
private EntityManager entityManager;
public void addTestData()
{
Person p = new Person();
p.setName("JOE");
entityManager.persist(p);
Hobby h1 = new Hobby();
h1.setName("h1");
h1.setPerson(p);
entityManager.persist(h1);
}
public List<Person> getTestData()
{
TypedQuery<Person> gridQuery = entityManager.createQuery("SELECT e FROM Person e", Person.class);
return gridQuery.getResultList();
}
}
EDIT Client:
InitialContext context = new InitialContext();
Testing test = (Testing)context.lookup("java:global/dst2_1/TestingBean");
test.addTestData();
for(Person p: test.getTestData()) {
System.out.println(p.getName());
for(Hobby b : p.getHobbys()) {
System.out.println(b.getName());
}
}
context.close();
Using MySQL - Storing the data works. But if I fetch the data only the person is returned - not hobbies. Coudld you tell me what is wrong in my code?
EDIT sorry have tried so many things ... The code shown as above produces:
Exception Description: An attempt was made to traverse a
relationship using indirection that had a null Session. This often
occurs when a n entity with an uninstantiated LAZY relationship is
serialized and that lazy relationship is traversed after
serialization. To avoid this issue, ins tantiate the LAZY
relationship prior to serialization.
But the Person is returned correctly. Why does it specify LAZY while I am using EAGER?
You code looks correct. I can't see any way that the EAGER could be ignored.
Are you sure you get the error with this attribute, not another one?
Also ensure you recompile and deployed your code correctly. You most like have an old version deployed.
Make the eager object Serializable
I have two or more tables resembles each other.
PARENT
ID | PK
NAME | VARCHAR
CHILD
ID |PK
NAME | VARCHAR
AGE | INT
It's not #Inheritance situation because they are independent entities and related to each other by #OneToMany or #ManyToOne.
I create entity class for each other.
#Entity
public class Parent {
#Id
private Long id;
private String name;
#ManyToOne(mappedBy = "parent")
private Collection<Child> children;
}
#Entity
public class Child {
#Id
private Long id;
private String name;
private int age;
#OneToMany
private Parent parent;
}
Is there any nice way to share common fields mappings?
// #MappedSuperclass // is this what it is exactly for?
public abstract class Base {
// #Id protected Long id; // ##?
#Column(name = "name", nullable = false)
private String name;
}
#Entity
public class Parent extends Base {
#Id
#TableGenerator(...)
#GeneratedValue(...)
protected Long id;
#ManyToOne(mappedBy = "parent")
private Collection<Child> children;
}
#Entity
public class Child extends Base {
#Id
#TableGenerator(...)
#GeneratedValue(...)
protected Long id;
private int age;
#OneToMany
private Parent parent;
}
Is this OK?
Is it even possible declaring #Id protected Long id; on the Base leaving #TableGenerator and #GeneratedVAlue on extended classes?
Is there any nice way to share common fields mappings?
MappedSuperclass is exactly right tool for that.
Is it even possible declaring #Id protected Long id; on the Base
leaving #TableGenerator and #GeneratedVAlue on extended classes?
No, it is not possible.