Hi Patrick
I will be able to get the exact information retruned later when I am back home.
I am trying to display a list of the items returned from the query in a JList (javax.swing.JList).
A JList takes either an array, a ListModel or a Vector; I was trying to use a Vectory as I
can just add elements to it and not worry about memory allocation or the size of the Vector
being too large.
My point is that when I tried to cast the resulting data from the query I got an exception.
Cannot Cast Delegate org.apache.openjpa
I will get the exact data this evening when i get home
Thanks
David
----- Original Message ----
From: Patrick Linskey <plinskey@gmail.com>
To: users@openjpa.apache.org; david.m.beer@btinternet.com
Sent: Monday, 21 January, 2008 11:52:15 PM
Subject: Re: Understanding getResultList()
Hi,
> and in return I am seeing a list containing a delegate and a
> persistence object.
Can you include a printout of the data you see, or some more detailed
explanation, such as class names of the instances returned?
> display. This is fine with a small amount of records but what about a
> large amount of records.
Are you concerned about the overhead involved in iterating through a
result list fully just to copy it over to the Vector? If the framework
that you are using does not provide any interface-based support, then
you might not have many options. One idea might be to try to create a
subclass of Vector that overrides most methods to just return values
from the actual backing list.
-Patrick
On Jan 21, 2008 3:34 PM, David Beer <david.m.beer@btinternet.com>
wrote:
> Hi All
>
> I have a n issue with using Query getResultList(), I am executing a
> nativeQuery("SELECT * FROM ENTRY", Entry.class). And performing the
> query like so List<Entry> results =
(List<Entry>)query.getResultList();
> and in return I am seeing a list containing a delegate and a
> persistence object.
>
> My main problem is that I am trying to display the resulting data
that
> comes back in a JList, in order to set the list data on a JList you
have
> to have the data in a Vector. So when I tried to cast the List to a
> Vector I got an exception.
>
> When I perform the same query using TopLink I get back a list of
Objects
> of the type and no extra information. At the moment I am going
through
> the results and getting each Object element and adding to Vector to
> display. This is fine with a small amount of records but what about a
> large amount of records.
>
> What is the best way of getting back just a list of Objects no
> additional data?
>
> Thanks
>
> David
>
--
Patrick Linskey
202 669 5907
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