ManyToMany association within conversation scope bean

[avpavlov]

Hi all.

I have 2 entities linked via many-to-many association

@Entity
@Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
public class User implements Serializable {
 @Id
 @GeneratedValue
 private long id;

 @NotEmpty
 @Column(unique = true)
 private String username;

 @ManyToMany(cascade = CascadeType.ALL)
 @JoinTable(
 name="UserToProvider",
 joinColumns = { @JoinColumn( name="user_id") },
 inverseJoinColumns = @JoinColumn( name="provider_id")
 )
 private Collection<Provider> providers = new ArrayList<Provider>();
}

@Entity
@Table(name="Provider" )
@Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
public class Provider implements Serializable {
 @Id
 @GeneratedValue
 private int id;
 @NotNull
 private String UPI; //Unique Provider identifier

 @ManyToMany(mappedBy="providers", cascade = CascadeType.ALL, fetch = FetchType.EAGER)
 private Collection<User> users;
}

Users list displayed on Provider form

....
 <h:panelGrid title="Users">
 <ui:repeat var="user" value="#{providerFormAction.provider.users}">
 <h:commandLink value="#{user.firstName} #{user.lastName}" action="#{userFormAction.view(user)}"/>
 <br/>
 </ui:repeat>
 <h:commandButton action="#{userFormAction.addNew}" value="Add new"/>

...

userFormAction.addNew() and .view() methods are marked as starting nested conversation. Save() method finihes current converastion and restore parent.

public class UserFormAction implements java.io.Serializable {
 @In
 EntityManager entityManager = null;

 @In
 Conversation conversation;

 private User user = null;

 @Begin(nested=true)
 public String addNew() {
 user = new User();
 return "/jspx/userForm.jspx";
 }

 @Begin(nested=true)
 public String view(User u) {
 user = u;
 return "/jspx/userForm.jspx";
 }

 public void save() {
 entityManager.persist(user);

 // tried flush - it did not help!!!
 // entityManager.flush();

 // to return to previous conversation
 conversation.endAndRedirect();
 }

 ....

After returning to Provider form it is still displaying OLD links (i.e. if I created new user linked to this provider - it is not displayed, if I removed link - it is still displayed as linked), although username is refreshed!

If I clear conversationId in browser address bar then links become correct.

Looks like marked as "mappedBy" end of many-to-many association is not refreshed properly in Seam - I tested other fields type - simple properties, ManyToOne, active end of ManyToMany - all refreshed properly OR I'M WRONG?.

[pmuir]

Seam is not caching part of your entity - perhaps hibernate is though in the persistence context?

[avpavlov]

... hibernate is though in the persistence context?

I'm not sure I understand that :) Could you please clarify? Do you mean hibernate fetched collection to Provider bean and did not refresh when User form saved (== links changed)? If yes, why usernames were refreshed - these referenced from collection and refreshed properly.

I agree that probaly I'm wrong when blame Seam but there are a lot of annotations and I assumed that some combination (or simply missed) annotations lead to this side effect.

At the moment I "brute-forced" it :) - set event listener to post-ins/upd/del event, register provider form method as event observer and check for collections inconsistencies

 if (r instanceof User) {
 User u = (User)r;
 if (getProvider().getUsers().contains(u) != u.getProviders().contains(getProvider())) {
 entityManager.refresh(getProvider());
 }
 }

It works but I'm sure there is better solution (at least not so "in-place").