Hi, I am using Spring 2.0.8, Hibernate 3.2.2GA and PostgresSQL 8, and I am having problems with duplicating collections.

I have two classes ClassA and ClassB with property Set<Attachment> attachments.

When I want to copy attachment list from classA to classB using java's:

classB.getAttachment().addAll(classA.getAttachments());

the original list in classA will get deleted from the database when I store the classB object:

session.saveOrUpdate(classB);

What is the "right" way to duplicate collections. I want to store both sets separately but classB's list having objects from classA's set.

I have mapped the Set<Attachment> like this using xdoclet:

* @hibernate.key column="class_a_id"
* @hibernate.many-to-many class="my.example.Attachment" column="attachment_id"
* @hibernate.set
* table = "class_a_attachments"
* sort = "natural"

Thank you for reading.

Ciao,

First of all I use Nhibernate so you need to try this with Hibernate to see how it works. But I will give you a general suggestion ...

I think the first thing you should do is after retreiving the list from classA is to create a method that makes a clone of the list but be careful to change the ID(key) to reflect the class they belong to. Try saving after that and see if anything changes.

Good luck!

Hi Yen,

Can you give more details on the structure of your ClassA, ClassB and Attachment are you using bi-directional mapping or uni-directional.



may be it will add the references to classB might not be new Attachment objects.