Filter on List - null elements - very interesting

[CatchSandeepVaid]

Say i have one-to-many relationship between Product and ProductNames. So Product has a List of ProductNames.


Actually we are using List for productNames.an d for list, in order to maintain the sequence, it stores the sequence in
extra seperate column in DB.
Now say, after applying the filer conditions, 0th, 2nd and 5th element (out of 10 )of the list gets selected..
Returned list size will of size 6 with 1st,3rd and 4th element as null and 0th,2nd and 5th element properly populated.
I guess this is done in hibernate for maitaining ordering of List.
What should i do if i don't want these null elements in the returned List?

[r035198x]

Please do not start multiple threads for the same problem.
Use the removeAll method to remove the nulls.

[CatchSandeepVaid]

Actually the problem is not just simple,
if we consider the entire tree graph(including associations and collections), removing null manulaly from all collections will be a tedious task

[r035198x]

You said you are getting a List with nulls and you want to remove the nulls. removeAll will remove all the nulls in the list. What is the problem now?

[CatchSandeepVaid]

Actually i have written a generic method which accepts the association names and collection names and creates a inner join fetch between them at runtime (using filters also). and i just execute the dynamically generated HQL which returns me root domain object with it's few associations and collections collections populated (which i have asked for)...Now i don;t know which relationship name represented association and which represented collection.. so i can't resume null in a generic way..

[dmjpro]

I am having the code like this ....

        List li = new Vector();
        li.add(12);
        li.add(null);
        li.add(null);
        li.add(13);
        li.add(15);
        li.add(null);
        List an_li = new Vector();
        an_li.add(null);
        li.removeAll(an_li);
        System.out.println(li.size());

It's also very interesting ;)

[r035198x]

Actually i have written a generic method which accepts the association names and collection names and creates a inner join fetch between them at runtime (using filters also). and i just execute the dynamically generated HQL which returns me root domain object with it's few associations and collections collections populated (which i have asked for)...Now i don;t know which relationship name represented association and which represented collection.. so i can't resume null in a generic way..

I'm sorry to say but this all sounds a bit confused. Better let it return data that you can understand.

[JosAH]

It's also very interesting ;)

What's so interesting about it? Its behaviour is exactly as described: it takes the difference of two (multi) sets. Nothing spectacular and nothing surprising.

kind regards,

Jos

[dmjpro]

What's so interesting about it? Its behaviour is exactly as described: it takes the difference of two (multi) sets. Nothing spectacular and nothing surprising.

kind regards,

Jos

No no, i didn't mean what you thought ;)
Actually it's according to the title .....