Re: EntityManager EclipseLink problem?

It sounds like Caching https://wiki.eclipse.org/EclipseLink/Examples/JPA/Caching <https://wiki.eclipse.org/EclipseLink/Examples/JPA/Caching>

Wade


===================

Wade Chandler
e: [email protected]



> On Dec 7, 2016, at 16:11, Mark Wade <[email protected]> wrote:
> 
> Hello,
> 
> I'm somewhat hesitant to post this as I'm not sure this forum is the proper place or that I can provide enough information in an appropriate manner such as to be of any help but I'm going to give it a shot anyway.
> 
> 
> I used the new entity classes from database wizard to create, among others, the classes Item and Category. An item has a category and a category can have many items and NetBeans has generated a itemsCollection in Category.  One of the views on the data is a BeanTreeView whose root node contains CategoryBeanNodes whose instanceContent contains a category and whose leaf nodes are ItemBeanNodes whose instanceContent contains an item.
> 
> 
> As I edit the items and save the edits I need to update the view accordingly. Now, especially when moving an item from one category to another, the first edit/save cycle was fine so I thought all was good but then somewhere I moved the item to another category, saved, and then back again and saved and then maybe a third edit/save cycle and my view was no longer displaying the data properly, either showing the item in  two categories or not moving the item at all.
> 
> 
> Now, I refresh the view after the transaction is committed and the entityManager is closed and at that point the database is in the proper state and to refresh the view I create a named query to get all the categories but the resultList is not what is in the database. Either the category's itemCollection doesn't contain the item it should or it contains an item that should no longer be there.  I've come up with a workaround and ,while it works, it seems pretty ugly to me and I don't know why I should need to do it. Basically I'm iterating through the resultList and checking if the categories' itemCollections are in the state expected and if not correcting them.
> 
> 
> But why should this be so?  Maybe this is of use:
> 
> public class Item implements Serializable {
> 
> ...
> 
> @JoinColumn(name = "category_id", referencedColumnName = "id")
> @ManyToOne
> private Category categoryId;
> 
> ...
> }
> 
> public class Category implements Serializable {
> 
> ...
> 
> @OneToMany(mappedBy = "categoryId")
> private Collection<Item> itemCollection;
> 
> ...
> 
> }
> 
> 
> Thanks for taking the time to look,
> 
> -- Mark
> 
> 
>