how to update many-to-many collection (lazy-loading) in hibernate/spring? - spring

Question

I have three tables and two classes.there are many-to-many relationship between the two tables/classes.
OYS_USER -->Many-to-Many with 'oys_lesson'
OYS_LESSON-->Many-to-Many with 'oys_user'
OYS_LESSON_STUDENT-->relationship
in User.class
#ManyToMany(cascade= CascadeType.ALL,fetch=FetchType.LAZY)
#JoinTable(name="oys_lesson_student",
joinColumns = { #JoinColumn(name="student_id",referencedColumnName="id")},
inverseJoinColumns = {#JoinColumn(name="lesson_id",referencedColumnName="id") })
#Fetch(FetchMode.SUBSELECT)
private Set<Lesson> studentLessons;
in Lesson.class
#ManyToMany(cascade=CascadeType.ALL,fetch=FetchType.LAZY)
#JoinTable(name = "oys_lesson_student", joinColumns = { #JoinColumn(name = "lesson_id", referencedColumnName = "id") }, inverseJoinColumns = { #JoinColumn(name = "student_id", referencedColumnName = "id") })
#Fetch(FetchMode.SUBSELECT)
private Set<User> lessonStudents;
I updated collection with below codes:
#Override
public void addLessonToStudent(Lesson lesson) {
// TODO Auto-generated method stub
String username = SecurityContextHolder.getContext()
.getAuthentication().getName();
Criteria criteria = openSession().createCriteria(User.class)
.add(Restrictions.eq("username", username));
User user=(User) criteria.uniqueResult();
log.info("'"+lesson.getLessonName()+"' lesson added to '"+user.getUsername()+"'");
/*user.getStudentLessons().add(lesson);
updateUser(user);
*/
lesson.getLessonStudents().add(user);
updateLesson(lesson);
} catch (HibernateException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
#Override
public void updateLesson(Lesson lesson) {
log.info(lesson.getLessonName()+" updated.");
openSession().update(lesson);
}
When I added current user to lesson's collection (or lesson to current user's collection).
update/insert query does not appear in hibernate statistics(console-log).
So a record can not be added to any collection.
Basically,I want to add new object to many to many collection.What am I doing wrong?
I use hibernate 4.3.5.Final (to get rid of lazy loading exception)
I use org.springframework.orm.hibernate4.support.OpenSessionInViewFilter for rid of lazy loading exception).
I tried CascadeType.EAGER with FetchType.JOIN.But did not change the results.update/insert query does not appear in hibernate statistics(console-log).
I use below properties for hibernate in application-context.xml(spring-hibernate-configuration):
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
<prop key="hibernate.show_sql">true</prop>
<prop key="hibernate.generate_statistics">true</prop>
<prop key="hibernate.cache.use_second_level_cache">true</prop>
<prop key="hibernate.cache.use_query_cache">true</prop>
<prop key="hibernate.cache.region.factory_class">org.hibernate.cache.ehcache.EhCacheRegionFactory
</prop>
<prop key="hibernate.enable_lazy_load_no_trans">true</prop>
<prop key="use_sql_comments">true</prop>
<prop key="hibernate.bytecode.use_reflection_optimizer">true</prop>
<prop key="hibernate.connection.autocommit">true</prop>
<prop key="net.sf.ehcache.configurationResourceName">/myehcache.xml</prop>
</props>
</property>
and spring txManager:
<!-- Enable the configuration of transactional behavior based on annotations -->
<tx:annotation-driven transaction-manager="txManager" />
<!-- Transaction Manager is defined -->
<bean id="txManager"
class="org.springframework.orm.hibernate4.HibernateTransactionManager">
<property name="sessionFactory" ref="SessionFactory" />
</bean>
I use spring/security,hibernate 4.3.5.Final,jpa2.1,jsf2.2. Thanks in advance.

Answer 1

You are almost there.
Firstly, you need to decide which site of your reletionship is 'in control'. Is the user or is it the lesson. And yo define the join table only on one of them so for example:
- you leave the user as it is
- on lesson you changed
#ManyToMany(mappedBy="studentLessons" ...)
Then, you need to add the reletionship manually to both sites of the relationship (in reality adding to the one in charge of mapping is typically enought).
so
user.getUserLesseson().add(lesson);
lesson.getLessonStudents().add(user);
if both are issued inside transaction it will result in the insert