Hi,
Is there a reason to use a java.util.List interface in the first place?
Which is quite big to implement for many people, why not define an
Interface alike javax.swing.ListModel? For example
Public interface IListViewModel
{
public Object getObjectAt(int index);
public int getSize()
//more needed?
}
I think many people have to put there own list objects in a
(Lazy)ArrayList again...which they do already hold in (lazy loading)
models.
Regards Jan
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf
> Of Eelco Hillenius
> Sent: Tuesday, March 08, 2005 8:11 PM
> To: [email protected]
> Subject: Re: [Wicket-develop] should we make AbstractResource
> serializeable or not?
>
>
> We're in the process of reconsidering the ListView
> implementation alltogether I think.
>
> If you really want this, you could provide a custom list that
> does this. That list could lazily load it's size: when not
> set yet, you load the actual list (e.g. from a database), but
> when set, return it. And then the actual loading should occur
> when one of it's accessor methods (like get(int) is called.
>
> E.g (haven't tested it, but the idea should work):
>
>
> public class LazyList extends ArrayList
> {
> private int size = -1;
>
> private boolean loaded = false;
>
> public LazyList(List list)
> {
> addAll(list);
> }
>
> public int size()
> {
> if(size == -1)
> {
> load();
> this.size = super.size();
> }
> }
>
> public get(int index)
> {
> load();
> return super.get(index);
> }
>
> public void unload()
> {
> this.loaded = false;
> }
>
> private void load()
> {
> if(!loaded)
> {
> this.loaded = true;
> // do loading here and call super.addAll(..)
> }
> }
>
> .... etc ....
>
>
> }
>
> and your model is like:
>
> public class MyModel extends AbstractDetachableModel
>
> private LazyList myList; // keep reference to list allways;
> it'll usually be empty
>
> protected void onAttach()
> {
> if(myList == null)
> {
> myList = new LazyList(getSomeList());
> }
> }
>
> protected void onDetach()
> {
> myList.unload();
> }
>
> protected Object onGetObject(Component component)
> {
> return myList;
> }
>
> .... etc ....
>
>
>
> Btw, this might be a usefull pattern to either put on the
> Wiki or in contrib. It's far more efficient for those cases
> where you have a list that doesn't change over requests, are
> that you want to 'push' the changes in, together with a
> ListView that doesn't remove it's items on each request.
>
>
> Eelco
>
> >
> >
> >It just happens that in my case - using a ListView - the
> list view calls
> >getModelObject within the onRender method (via getViewSize)
> this is causing
> >my detached model to re-attach for every request - even repeated
> >IredirectListener requests.
> >
> >Could this component possibly be changed to remember the
> size of the list ?
> >
> >Cameron
> >
> >
> >
>
>
>
> -------------------------------------------------------
> SF email is sponsored by - The IT Product Guide
> Read honest & candid reviews on hundreds of IT Products from
> real users.
> Discover which products truly live up to the hype. Start reading now.
> http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click
> _______________________________________________
> Wicket-develop mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/wicket-develop
>
-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now.
http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click
_______________________________________________
Wicket-develop mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/wicket-develop
