Concerns about TreeTableViews ability to display UNlimited number of rows of data

[Martin Klähn]

https://javafx-jira.kenai.com/browse/RT-32390

- Martin


On Fri, Aug 16, 2013 at 10:02 AM, Martin Klähn <grazertwo at gmail.com> wrote:

> Okay, will do.
> Thx
>
> - Martin
> Am 16.08.2013 10:00 schrieb "Jonathan Giles" <jonathan.giles at oracle.com>:
>
>  No, I've not had a chance to think more about it. The best thing to do
>> is file a Jira tweak request.
>>
>> -- Jonathan
>> Sent from a touch device. Please excuse my brevity.
>>
>> "Martin Klähn" <grazertwo at gmail.com> wrote:
>>>
>>> Hi,
>>>
>>> Sorry to be pestering you with it but have you had a chance to think
>>> some more about this. It it will help I could put into code what I'm trying
>>> to do and I perceive to be the limitation.
>>> I could put that back on the list to get back from these backwater
>>> personal discussions ;-)
>>>
>>> - Martin
>>> Am 15.08.2013 12:16 schrieb "Martin Klähn" <grazertwo at gmail.com>:
>>>
>>>> I can. However it wouldn't do much good. The entire collection would
>>>> still be copied from my source to parent children collection.
>>>>
>>>> Going with the example in the javadoc, if you had a folder with tens of
>>>> thousands of files/folders in it then as soon as you expand the TreeItem
>>>> for that folder a TreeItem would be created for every single files in that
>>>> folder and not only for the files that can be displayed on the screen.
>>>>
>>>> So if instead of the described method buildChildren(TreeItem<File>
>>>> TreeItem) you had
>>>>
>>>> private static class FilesOL extends ObservableListBase<TreeItem<File>>
>>>> {
>>>>
>>>>     private final File[] files;
>>>>
>>>>     public FilesOL(File[] files) {
>>>>         this.files = files;
>>>>     }
>>>>
>>>>     @Override
>>>>     public TreeItem<File> get(int index) {
>>>>         // lazy create
>>>>         // posibly add caching
>>>>         return createNode(files[i]);
>>>>     }
>>>>
>>>>     @Override
>>>>     public int size() {
>>>>         return files.length;
>>>>     }
>>>> }
>>>>
>>>> private ObservableList<TreeItem<File>> buildChildren(TreeItem<File>
>>>> TreeItem) {
>>>>     File f = TreeItem.getValue();
>>>>     if (f != null && f.isDirectory()) {
>>>>         File[] files = f.listFiles();
>>>>         if (files != null) {
>>>>             return new FilesOL(files);
>>>>         }
>>>>     }
>>>>
>>>>     return FXCollections.emptyObservableList();
>>>> }
>>>>
>>>> FilesOL.get(int) would be triggered for each and every entry it has in
>>>> all three previously stated ways to set the children.
>>>>
>>>>
>>>>
>>>>
>>>> On Thu, Aug 15, 2013 at 11:44 AM, Jonathan Giles <
>>>> jonathan.giles at oracle.com> wrote:
>>>>
>>>>> As in the example I linked to, can't you override the getChildren() to
>>>>> do this?
>>>>>
>>>>> -- Jonathan
>>>>> Sent from a touch device. Please excuse my brevity.
>>>>>
>>>>> "Martin Klähn" <grazertwo at gmail.com> wrote:
>>>>>>
>>>>>> Thanks for the quick response.
>>>>>>
>>>>>> Yes, lazy determination children list is possible and I've been there.
>>>>>>
>>>>>> Say I have an implementation of ObservableList<TreeItem<T>>
>>>>>> lazyChildren that is capable of lazy creation of TreeItems. That
>>>>>> list will get triggered for all entries by
>>>>>> a) Bindings.bindContent(super.getChildren(), lazyChildren)
>>>>>> b) super.getChildren().addAll(lazyChildren)
>>>>>> c) super.getChildren().setAll(lazychildren)
>>>>>>
>>>>>> What I'm missing is a constructor in TreeItem where I can give it the
>>>>>> ObservableList to use as children. Similiar to
>>>>>> http://docs.oracle.com/javafx/2/api/javafx/scene/control/TableView.html#TableView%28javafx.collections.ObservableList%29
>>>>>> .
>>>>>>
>>>>>> - Martin
>>>>>>
>>>>>>
>>>>>> On Thu, Aug 15, 2013 at 10:57 AM, Jonathan Giles <
>>>>>> jonathan.giles at oracle.com> wrote:
>>>>>>
>>>>>>> In on my phone, so I'll keep this really brief. I have one suggested
>>>>>>> approach in the TreeItem javadoc here:
>>>>>>>
>>>>>>>
>>>>>>> http://docs.oracle.com/javafx/2/api/javafx/scene/control/TreeItem.html
>>>>>>>
>>>>>>> Perhaps this will help. I can look into it deep power tomorrow if
>>>>>>> necessary.
>>>>>>>
>>>>>>> -- Jonathan
>>>>>>> Sent from a touch device. Please excuse my brevity.
>>>>>>>
>>>>>>>
>>>>>>> "Martin Klähn" <grazertwo at gmail.com> wrote:
>>>>>>>>
>>>>>>>> Hi guys,
>>>>>>>>
>>>>>>>> I've now worked with TreeView and TreeTableView to some extent.
>>>>>>>>
>>>>>>>> TableView as well as TreeTabelView are designed to visualize an unlimited
>>>>>>>> number of rows of data, broken out into columns".
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> For TableView I can understand that concept as i can pass the TableView the
>>>>>>>> ObservableList containing the data. The Implementation of that
>>>>>>>> ObservableList can do lazy loading of the available data although it has to
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> know how many dataset there are. So far so good.
>>>>>>>>
>>>>>>>> However for TreeTableView and by extension TreeView (no comment about
>>>>>>>> unlimited number of rows of data there) I do not agree with that statement
>>>>>>>> with my current understanding of the API.
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> The only way I can set the children of an TreeItem is by
>>>>>>>> a) adding the child items to the ObservableList retrieved from
>>>>>>>> TreeItem.getChildren() where have to create all children elements and add
>>>>>>>> them (not LAZY) or
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> b) bind a ObservableList to TreeItem.getChildren() but that essentially
>>>>>>>> first copies all items from the bound list to that of
>>>>>>>> TreeItem.getChildren() (not LAZY).
>>>>>>>>
>>>>>>>> So in order to visualize an unlimited number of rows of data with
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> TreeTableView and I'm not missing something I have to fully initialize an
>>>>>>>> unlimited amount of data.
>>>>>>>>
>>>>>>>> Please tell me I've missed something!
>>>>>>>>
>>>>>>>>
>>>>>>>> - Martin
>>>>>>>>
>>>>>>>>
>>>>>>
>>>>