JPA One To Many Relationship Persistence Bug
- by Brian
Hey folks,
I've got a really weird problem with a bi-directional relationship in jpa (hibernate implementation). A User is based in one Region, and a Region can contain many Users.
So...relationship is as follows:
Region object:
@OneToMany(mappedBy = "region", fetch = FetchType.LAZY, cascade = CascadeType.ALL)
public Set<User> getUsers() {
return users;
}
public void setUsers(Set<User> users) {
this.users = users;
}
User object:
@ManyToOne(cascade = {CascadeType.PERSIST, CascadeType.MERGE}, fetch = FetchType.EAGER)
@JoinColumn(name = "region_fk")
public Region getRegion() {
return region;
}
public void setRegion(Region region) {
this.region = region;
}
So, the relationship as you can see above is Lazy on the region side, ie, I don't want the region to eager load all the users. Therefore, I have the following code within my DAO layer to add a user to an existing user to an existing region object...
public User setRegionForUser(String username, Long regionId){
Region r = (Region) this.get(Region.class, regionId);
User u = (User) this.get(User.class, username);
u.setRegion(r);
Set<User> users = r.getUsers();
users.add(u);
System.out.println("The number of users in the set is: "+users.size());
r.setUsers(users);
this.update(r);
return (User)this.update(u);
}
The problem is, when I run a little unit test to add 5 users to my region object, I see that the region.getUsers() set always stays stuck at 1 object...somehow the set isn't getting added to.
My unit test code is as follows:
public void setUp(){
System.out.println("calling setup method");
Region r = (Region)ManagerFactory.getCountryAndRegionManager().get(Region.class, Long.valueOf("2"));
for(int i = 0; i<loop; i++){
User u = new User();
u.setUsername("username_"+i);
ManagerFactory.getUserManager().update(u);
ManagerFactory.getUserManager().setRegionForUser("username_"+i, Long.valueOf("2"));
}
}
public void tearDown(){
System.out.println("calling teardown method");
for(int i = 0; i<loop; i++){
ManagerFactory.getUserManager().deleteUser("username_"+i);
}
}
public void testGetUsersForRegion(){
Set<User> totalUsers = ManagerFactory.getCountryAndRegionManager().getUsersInRegion(Long.valueOf("2"));
System.out.println("Expecting 5, got: "+totalUsers.size());
this.assertEquals(5, totalUsers.size());
}
So the test keeps failing saying there is only 1 user instead of the expected 5. Any ideas what I'm doing wrong?
thanks very much,
Brian
