RFR: 8279640: ListView with null SelectionModel/FocusModel throws NPE

[Andy Goryachev]

On Sat, 8 Jan 2022 00:17:36 GMT, Marius Hanl <mhanl at openjdk.org> wrote:

> This PR fixes a bunch of NPEs when a null `SelectionModel` or `FocusModel` is set on a `ListView`.
> 
> The following NPEs are fixed (all are also covered by exactly one test case):
> NPEs with null selection model:
> - Mouse click on a `ListCell`
> - SPACE key press
> - KP_UP (arrow up) key press
> - HOME key press
> - END key press
> - BACK_SLASH + CTRL key press
> 
> NPEs with null focus model:
> - SPACE key press
> - Select an items: getSelectionModel().select(1)
> - Clear-Select an item and add one after: listView.getSelectionModel().clearAndSelect(1); listView.getItems().add("3");

you are right!  unless, of course, someone writes code to invoke these methods directly.  For example, simpleSelect() is protected, so any Behavior that extends CellBehaviorBase might encounter an NPE.

but again, these are being addressed in another PR.

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PR: https://git.openjdk.org/jfx/pull/711