RFR: 8283214: [macos] Screen magnifier does not show the magnified text for JcomboBox [v2]

[Alexey Ivanov]

On Wed, 21 Jun 2023 08:56:37 GMT, Abhishek Kumar <abhiscxk at openjdk.org> wrote:

>> I mean `getAccessibleChild(..., 1)` can still return null (when both `if`s of `case 1` resolve to false). Let's consider the following code:
>> 
>> public void doSmthWith(JComponent component, BasicComboBoxUI ui) {
>>     if (ui.getAccessibleChildrenCount(component) > 1) {
>>         // well, we have at least 2 components, so we can expect to get a valid object below
>>         final var ac = ui.getAccessibleChild(component, 1)
>>                                   .getAccessibleContext(); // <= possible NPE
>>         // ...
>>     }
>> }
>> 
>> 
>> I think we have to return 1 from `getAccessibleChildrenCount(...)` for the cases when `getAccessibleChild(..., 1)` returns `null`
>
> I think it is not needed to return 1 from `getAccessibleChildrenCount(...)`.  `getAccessibleChildrenCount(...)` is used to get the exact number of accessible child for a component and afterwards `getAccessibleChild(..., index)` method can be invoked to get the child.
> 
> It should be ok to return null if the switch case condition fails or index doesn't match with case statement. Although chances of returning null is very unlikely for index 0 and 1.

I tend to agree… there are now two children; if the condition in `getAccessibleChild` fails, it returns `null`. Nothing has changed, there's a possibility that it would return `null`. Yet it shouldn't because both editor and button implement `Accessible`.

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PR Review Comment: https://git.openjdk.org/jdk/pull/14497#discussion_r1246631766