RFR: 6510914: JScrollBar.getMinimumSize() breaks the contract of JComponent.setMinimumSize() [v6]

[Alexey Ivanov]

On Mon, 20 Nov 2023 12:54:25 GMT, Alexey Ivanov <aivanov at openjdk.org> wrote:

> > > But I do have another suggestion that actually might have been the best thing to do all those years ago. Keep the over-ride as the default behaviour, and document it better. But if the app calls setMaximumSize or setMinimumSize() then honour it like you are supposed to. I suspect very few apps actually call these since they are complete no-ops today. If we do that, then yes, you'll still see differences if you do call those APIs and forgot about it because it didn't make a difference.
> > 
> > 
> > Do you mean this way https://openjdk.github.io/cr/?repo=jdk&pr=15325&range=01#sdiff-0-src/java.desktop/share/classes/javax/swing/JScrollBar.java what I had done in the initial iteration? I guess that change will still show the above problem during frame resize, where scrollbars are not rigid
> 
> This is how I understand Phil's comment.

As I understand Phil's comment, he suggests using the implementation that you used in the first iteration of this fix:

https://github.com/openjdk/jdk/blob/31bbdee8ea71f43eb4863af50b398170a7b81ed2/src/java.desktop/share/classes/javax/swing/JScrollBar.java#L762-L772

That is we preserve the current behaviour of `getMinimumSize()` and `getMaximumSize()` methods in `JScrollBar`, yet if `setMinimumSize()` or `setMaximumSize()` is called, the corresponding `get-` methods return the set value and thus they follow the contract specified in `JComponent`.

@prrace, could you confirm, please?

> > I guess that change will still show the above problem during frame resize, where scrollbars are not rigid
> 
> Yes, it will, this is why update to the javadoc of `getMinimumSize` and `getMaximumSize` is required—to document their default behaviour and the fallback to returning the set sizes as per `JComponent` specification of `setMinimumSize` and `setMaximumSize`.

Maybe, overriding `setMinimumSize` and `setMaximumSize` isn't needed if we respect the `JComponent` contract. However, the specification of `getMinimumSize` and `getMaximumSize` needs updating to clarify what is returned.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/15325#issuecomment-1864824123