<AWT Dev> Proposal for consolidation of KeyboardFocusManagerPeer

[Oleg Sukhodolsky]

KFMPeerImpl looks more reasonable for me too :)

Oleg.

On Tue, Nov 15, 2011 at 12:10 PM, Anton Tarasov
<anton.tarasov at oracle.com> wrote:
> Hi Roman,
>
> The peer methods you mentioned contain the following comment:
>
> // TODO: consider moving it to KeyboardFocusManagerPeerImpl
>
> So, it would be fine to do it.
>
> Thanks,
> Anton.
>
> On 11/15/2011 1:35 AM, Roman Kennke wrote:
>>
>> Hi there,
>>
>> One thing that's bugging me for a while is how the ComponentPeer's
>> requestFocus() method is supposed to work. As far as I could figure out,
>> it's basically always like this (I use KFMHelper to call the
>> corresponding KeyboardFocusManager's private methods by reflection):
>>
>>     public boolean requestFocus(Component lightweightChild, boolean
>> temporary,
>>             boolean focusedWindowChangeAllowed, long time, Cause cause)
>> {
>>         if (KFMHelper.processSynchronousLightweightTransfer(window,
>>                 lightweightChild, temporary, focusedWindowChangeAllowed,
>> time)) {
>>             return true;
>>         }
>>
>>         int result = KFMHelper.shouldNativelyFocusHeavyweight(window,
>>                 lightweightChild, temporary, focusedWindowChangeAllowed,
>> time,
>>                 cause);
>>
>>         switch (result) {
>>         case KFMHelper.SNFH_FAILURE:
>>             return false;
>>         case KFMHelper.SNFH_SUCCESS_PROCEED:
>>                     requestFocusImpl(window, lightweightChild,
>> temporary,
>>                                  focusedWindowChangeAllowed, time,
>> cause);
>>         case KFMHelper.SNFH_SUCCESS_HANDLED:
>>             // Either lightweight or excessive request - all events are
>>             // generated.
>>             return true;
>>         default:
>>             return false;
>>         }
>>     }
>>
>> The only thing that really differs between implementations would be the
>> requestFocusImpl() method call in the SNFH_SUCCESS_PROCEED case. The
>> rest seems to be the same in all implementations, except that in one
>> case (Windows I believe) it is done in JNI while in others (X11) it's
>> done by reflection.
>>
>> I think this can be consolidated by doing the above directly in the
>> KeyboardFocusManager, before calling the peer requestFocus(), and have
>> the peer's requestFocus() only do the requestFocusImpl() handling. This
>> way we could avoid duplicate code and avoid reflection/JNI altogether.
>>
>> Maybe I am missing something?
>>
>> If not, I would work on a patch to move the above KeyboardFocusManager
>> calls into the KFM and have the peer only bothers with the part that is
>> requestFocusImpl() in the above example. Does that sound reasonable? It
>> would certainly make some things simpler in OpenJDK as well as Cacio and
>> the JavaFX SwingView that I am working on.
>>
>> Best regards, Roman
>>
>>
>
>