[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-2599) Inconsistent behaviour with Cascade Refresh and lazy loaded collections

[Paul Benedict (JIRA)]

    [ http://opensource.atlassian.com/projects/hibernate/browse/HHH-2599?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=32732#action_32732 ] 

Paul Benedict commented on HHH-2599:
------------------------------------

I wonder if the spec is incomplete? The spec says "the state of the given instance will be re-read from the database" but a collection is not an entity. That's probably the rub. In my situation, I thought refreshing the parent would grab any new children. It turns out only to refresh the already loaded children. Doh!

> Inconsistent behaviour with Cascade Refresh and lazy loaded collections
> -----------------------------------------------------------------------
>
>                 Key: HHH-2599
>                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2599
>             Project: Hibernate Core
>          Issue Type: Bug
>          Components: core
>    Affects Versions: 3.2.3
>         Environment: 3.2.3, hsqldb/mysql
>            Reporter: Guy Chua
>         Attachments: cascadeTest.zip
>
>
> According to the specs for session.refresh(),  the state of the given instance will be re-read from the database. I have a model 'Company' that has 2 lazy collections, departments and employees.
> Snippet of class Company
> --------------------------------------------------------------------
>     @OneToMany (mappedBy="company", cascade={ CascadeType.ALL }) // POINT 1
>     private Set<Department> departments;                                                           // POINT 1
>     
>     @OneToMany (mappedBy="company", cascade={ CascadeType.ALL }) // POINT 2
>     private Set<Employee> employees;                                                                 // POINT 2
> Snippet of class CascadeTestRunner
> --------------------------------------------------------------------
>     public void doRefreshTest() {
>     	
>         session = sessionFactory.openSession();
>         session.getTransaction().begin();
>         
>         Company loadedCompany = (Company)session.get(Company.class, companyId);
>         logger.debug(loadedCompany);
>         
> //        session.refresh(loadedCompany); // POINT A
>         
>         session.close();
>         
>         Set<Department> loadedDepartments = loadedCompany.getDepartments();
>         logger.debug("TEST for LAZY DEPARTMENTS [START]");
>         
>         for (Department tmpDepartment : loadedDepartments) {
>         	logger.debug(tmpDepartment); // POINT B
>         }
>         logger.debug("TEST for LAZY DEPARTMENTS [END]");
>         
>         Set<Employee> loadedEmployees = loadedCompany.getEmployees();
>         logger.debug("TEST for LAZY EMPLOYEES [START]");
>         for (Employee tmpEmployee : loadedEmployees) {
>         	logger.debug(tmpEmployee); // POINT C
>         }
>         logger.debug("TEST for LAZY EMPLOYEES [END]");
>     }
> If I run the above code, Point B will give me LazyInitializationException which is the expected behavior. But if i uncomment POINT A, the LazyInitializationException happens at POINT C instead of POINT B. Why should POINT B pass and POINT C fail?
> Furthermore, with POINT A still uncommented and when I swap the position of POINT 1 with POINT 2, the LazyInitializationException happens at POINT B now. I am wondering why the position of the fields produce the exception at a different location.
> What happens when a lazy collection annotated with CascadeType.Refresh is refreshed? I am getting varied results, sometimes the collection is initialized, sometimes it is not. Is it supposed to cascade the refresh to lazy elements in the first place?
> Hope someone can shed some light on this.
> Test Results
> ------------------
> 1. LazyInitializationException at POINT B
>     @OneToMany (mappedBy="company", cascade={ CascadeType.ALL }) // POINT 1
>     private Set<Department> departments;                                                           // POINT 1
>     
>     @OneToMany (mappedBy="company", cascade={ CascadeType.ALL }) // POINT 2
>     private Set<Employee> employees;                                                                 // POINT 2
> //    session.refresh(loadedCompany); // POINT A
>     logger.debug(tmpDepartment); // POINT B
>     logger.debug(tmpEmployee); // POINT C
> 2. LazyInitializationException at POINT C
>     @OneToMany (mappedBy="company", cascade={ CascadeType.ALL }) // POINT 1
>     private Set<Department> departments;                                                           // POINT 1
>     
>     @OneToMany (mappedBy="company", cascade={ CascadeType.ALL }) // POINT 2
>     private Set<Employee> employees;                                                                 // POINT 2
>     session.refresh(loadedCompany); // POINT A
>     logger.debug(tmpDepartment); // POINT B
>     logger.debug(tmpEmployee); // POINT C
> 2. LazyInitializationException at POINT B when positions of POINT 1 and POINT 2 are swapped
>     @OneToMany (mappedBy="company", cascade={ CascadeType.ALL }) // POINT 2
>     private Set<Employee> employees;                                                                 // POINT 2
>     @OneToMany (mappedBy="company", cascade={ CascadeType.ALL }) // POINT 1
>     private Set<Department> departments;                                                           // POINT 1
>     
>     session.refresh(loadedCompany); // POINT A
>     logger.debug(tmpDepartment); // POINT B
>     logger.debug(tmpEmployee); // POINT C

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