Hi,
Can you please create a new CR using http://bugs.java.com
<http://bugs.java.com/> ?
It is too late to fix it in jdk9, but I think it will be possible to fix it in
10 and then backport to some update of jdk9.
>
> Good day,
>
> I believe I've hit my first bug in occasional testingof the JDK-9 drops.
> I hope this is an appropriate way to send feedback?
>
> We use a customised "tri-state" checkbox, which triggers a crash when the
> keyboard focus moves to it by pressing the TAB key. The issue seems related
> to some focus logic changes with button-groups introduced in JDK-9.
> (For example: 8074883?)
>
> The top of the stack trace is:
>
> java.lang.ClassCastException: com.example.TristateCheckBox$TristateDecorator
> cannot be cast to java.desktop/javax.swing.JToggleButton$ToggleButtonModel
> at
> java.desktop/javax.swing.LayoutFocusTraversalPolicy.accept(LayoutFocusTraversalPolicy.java:243)
> at
> java.desktop/javax.swing.SortingFocusTraversalPolicy.getComponentBefore(SortingFocusTraversalPolicy.java:435)
> at
> java.desktop/javax.swing.LayoutFocusTraversalPolicy.getComponentBefore(LayoutFocusTraversalPolicy.java:143)
> at
> java.desktop/java.awt.Component.transferFocusBackward(Component.java:8201)
> at
> java.desktop/java.awt.Component.transferFocusBackward(Component.java:8186)
> at
> java.desktop/java.awt.DefaultKeyboardFocusManager.focusPreviousComponent(DefaultKeyboardFocusManager.java:1388)
> at
> java.desktop/java.awt.DefaultKeyboardFocusManager.processKeyEvent(DefaultKeyboardFocusManager.java:1183)
> at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:4877)
> at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2317)
> at java.desktop/java.awt.Component.dispatchEvent(Component.java:4793)
> ...
>
> The relevant code in LayoutFocusTraversalPolicy.accept is:
>
> } else if (aComponent instanceof JComponent) {
> if (SunToolkit.isInstanceOf(aComponent,
> "javax.swing.JToggleButton")) {
> JToggleButton.ToggleButtonModel model =
> (JToggleButton.ToggleButtonModel) ((JToggleButton)
> aComponent).getModel(); // <- Line 243
> if (model != null) {
> ButtonGroup group = model.getGroup(); // <- Only use of 'model'
>
> For whatever reason (probably to do with the 3 states) the button model
> is not a ToggleButtonModel, but derived from a DefaultButtonModel.
>
> I think a simple solution is to (check? and) cast less specifically, to a
> DefaultButtonModel instead. That looks to be sufficient here, and is also
> what we find similar code in JToggleButton doing. For example in
> JToggeleButton.getGroupSelection we see:
>
> if (model instanceof DefaultButtonModel) {
> ButtonGroup group = ((DefaultButtonModel) model).getGroup();
> //...
>
> I note while JToggleButton creates a ToggleButtonModel by default, it
> does not enforce it via setModel().
>
>
> More background: I think we found this code (over a decade ago) from here
>
> http://www.javaspecialists.eu/archive/Issue082.html
>
> (There are better solutions implementing this GUI control these days, but
> I thought you might like to hear about it.)
>
> Kind regards,
> Luke Usherwood
>
>
