Ensuring order of child properties with JPA/EJB3?
When I have a one to many relationship, a simple parent child relationship, I specify the relationship like this:
@OneToMany(cascade = CascadeType.ALL, mappedBy ="reportType")
private List<ReportTypeValue> values;
But when the List is populated, the actual order of the elements is arbitrary, and varies depending on the whim of the database.
Is there a way to specify what order the children should be populated within the resulting collection?
# 2
how about if i want to order without using any of child's field?
I'd like to set who is going to be 1st, who's 2nd, etc.
something like:
child objects
c1[id=1, name=A]c2[id=2, name=B]c3[id=3, name=C]
and child order could be:
{c1, c2, c3} or {c2,c3,c1} or {c3,c1,c2} or etc.
# 4
I have to persist the order of those child objects, just sorting in the getter method won't work.
I came up with:
Create another persistent object that wraps the child object and has a position field. Then the relationship from parent is to the wrapper object. This way I have the original parent-child relationship plus "persistent-custom-ordering" of child objects.
might no be the smart solution, but it works...
Message was edited by:
Ronpon
