<AWT Dev> <Swing Dev> Public RequestFocusController/AWTAccessor API

[Semyon Sadetsky]

Okay... You said the you need to intercept the focus request in the 
place where the target is set.
 From my point of view opening 
Component#requestFocusInWindow(CausedFocusEvent.Cause cause) resolves that.
But it looks like you need extra. What is the final purpose? Maybe you 
want to reject focus transfer depending on the target?

--Semyon

On 4/14/2016 3:19 PM, Reto Merz wrote:
> Thanks for your investigation Semyon.
>
> Make Component#requestFocusInWindow(CausedFocusEvent.Cause cause) public/protected will not help us.
> I can explain it more detailed if you want.
>
> What would help is to introduce a "protected boolean Component#isRequestFocusAccepted()"
> which is invoked by Component#isRequestFocusAccepted(boolean,boolean,CausedFocusEvent.Cause)
> after the "Component.requestFocusController.acceptRequestFocus" statement (and only if acceptRequestFocus has returned true).
>
> This way you also don't have to make CausedFocusEvent.Cause public.
>
> Best Regards
> Reto Merz
>
> On 14/04/16 13:09, Semyon Sadetsky wrote:
>
> The FocusTraversalPolicy can be obtained using public API. It may give you the target. But I believe this is not what you would like to do...
>
> It seem sensible to make Component#requestFocusInWindow(CausedFocusEvent.Cause cause) public. Will it be enough for you?
>
> I could start to implement this right after the 8080395 push.
>
> --Semyon
>
> On 4/14/2016 12:30 PM, Reto Merz wrote:
> Hello Semyon,
>
> We need to know the target component: "which component will be focused".
> Target component means the component which should be "really" focused,
> so this can only be known after all the FocusCycle / FocusTraversalPolicy logic has processed.
>
> DefaultKeyboardFocusManager focusNextComponent/focusPreviousComponent
> provides only the source component. Not the target.
>
> The second argument of RequestFocusController#acceptRequestFocus is the "real" target component.
> We use only this argument in our custom RequestFocusController implementation.
>
> Thanks
> Reto Merz
>
> On 14/04/16 08:31, Semyon Sadetsky wrote:
> Hi Reto,
>
> It is unlikely that AWTAccessor API may be opened. It gives access to internal undocumented methods not to even mention that those methods have private and package accesses.
> As I understand you need the way to intercept focus transfer initiated by a traversal key. Why to subclass the DefaultKeyboardFocusManager to override its focusNextComponent/ focusPreviousComponent methods?
>
> --Semyon
>
> On 4/12/2016 2:37 PM, Reto Merz wrote:
> Hello Alexandr,
>
> Basically we need to detect and intercept focus changes.
>
> java.awt.Component allows to override this methods:
> requestFocus()
> requestFocus(boolean)
> requestFocusInWindow()
> requestFocusInWindow(boolean)
>
> requestFocus() is only invoked when the component is focused by a mouse click.
> But no requestFocus* method is invoked when a FocusTraversalPolicy is involed
> (f. e. the user press TAB to focus next component).
>
> sun.awt.RequestFocusController#acceptRequestFocus is invoked in both cases.
>
> Attached a demo to reproduce it:
> - if TextField is focused by a mouse click "requestFocus" and "acceptRequestFocus" is logged
> - if TextField is focused by TAB only "acceptRequestFocus" is logged
>
> Some more notes about the test program:
> ComponentAccessorDelegator delegates all calls to the original ComponentAccessor implementation.
> Only ComponentAccessor#setRequestFocusController is changed to keep our RequestFocusController implementation.
>
> I have just filled a RFE on http://bugreport.java.com/bugreport
>
> Thanks
> Reto Merz
>
>
> On 11/04/16 21:02, Alexander Scherbatiy wrote:
>   Hello Reto,
>
>   Could you provide use cases which illustrate tasks the requested API is intended to solve in your application?
>
>   Please, also create a request in the bug system http://bugreport.java.com/bugreport
>
>   Thanks,
> Alexandr.
>
> On 11/04/16 12:26, Alexander Scherbatiy wrote:
>
>   Resending the request to awt-dev alias.
>
>   Thanks,
>   Alexandr.
>
> On 4/4/2016 4:54 PM, Reto Merz wrote:
> Hello,
>
> Jigsaw will disallow access to internal packages.
> We have written a complex validation and focus management
> implementation for our closed-source RIA and maintain it since JRE
> 1.4.
>
> For this we use some internal API. We have a custom implementation of
> these interfaces:
>
> sun.awt.RequestFocusController
> sun.awt.AWTAccessor.ComponentAccessor
>
> And use this getter and setter:
>
> sun.awt.AWTAccessor#setComponentAccessor(AWTAccessor.ComponentAccesso
> r)
> sun.awt.AWTAccessor#getComponentAccessor()
> sun.awt.AWTAccessor.ComponentAccessor#setRequestFocusController(Reque
> stFocusController)
>
>
> Please make this API public.
>
> Furthermore we need to call
> java.awt.Component#revalidateSynchronously().
> We do this with reflection. It would be nice to have a public API for
> this.
> Maybe a new static method on AWTAccessor:
> AWTAccessor.revalidateSynchronously(Component)
>
> Best Regards
> Reto Merz
>
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