atom feed13 messages in net.java.openjdk.awt-devRe: <AWT Dev> Proposal for consolidat...
FromSent OnAttachments
Roman KennkeNov 14, 2011 1:34 pm 
Oleg SukhodolskyNov 14, 2011 10:16 pm 
Roman KennkeNov 14, 2011 11:51 pm 
Anton TarasovNov 15, 2011 12:10 am 
Oleg SukhodolskyNov 15, 2011 12:12 am 
Roman KennkeNov 15, 2011 1:43 am.patch
Oleg SukhodolskyNov 15, 2011 1:54 am 
Anton V. TarasovNov 15, 2011 3:10 am 
Roman KennkeNov 15, 2011 3:22 am 
Oleg SukhodolskyNov 15, 2011 3:32 am 
Anton V. TarasovNov 15, 2011 4:00 am 
Oleg SukhodolskyNov 16, 2011 3:51 am 
Oleg SukhodolskyNov 18, 2011 8:47 pm 
Subject:Re: <AWT Dev> Proposal for consolidation of KeyboardFocusManagerPeer
From:Oleg Sukhodolsky (son.@gmail.com)
Date:Nov 18, 2011 8:47:12 pm
List:net.java.openjdk.awt-dev

I've refreshed my memory (re-read the code :) and it looks like NullComponentPeer is not a problem since Component.requestFocus() always calls ComponentPeer.requestFocus() on heavyweight. But you still need to "reject focus requests" for peers which do not support it (such as WFileDialogPeer). Perhaps it is better to move even more code in Component so peerRequestFocus() would look like:

<some calls to KFM> requestAccepted = hw.peer.requestFocus(...); if (!requestAccepted) { KFM.removeLastFocusRequest(); } return requestAccepted; <rest of the code>

(and make sure that WFileDialog.requestFocus() and other such methods return false ;)

Oleg.

P.S. and, perhaps, peerRequestFocus() should be part of KFM (but it is up to you)

On Wed, Nov 16, 2011 at 3:51 PM, Oleg Sukhodolsky <son.@gmail.com> wrote:

On Tue, Nov 15, 2011 at 4:00 PM, Anton V. Tarasov <anto@oracle.com> wrote:

On 15.11.2011 15:32, Oleg Sukhodolsky wrote:

On Tue, Nov 15, 2011 at 3:23 PM, Roman Kennke<rom@kennke.org>  wrote:

Hi Anton,

On Tue, Nov 15, 2011 at 1:44 PM, Roman Kennke<rom@kennke.org>  wrote:

Find attached a patch that illustrates the idea (couldn't find a recent version of webrev tool online, at least not in http://openjdk.java.net/guide/codeReview.html/webrevHelp.html).

It basically moves identical/equivalent code from the peers to java.awt package. Notice that this is not yet complete, with this change, the methods shouldNativelyFocusHeavyweight() and processSynchronousLightweightTransfer() can be removed from the KeyboardFocusManagerAccessor and KeyboardFocusManagerPeerImpl classes.

Maybe I am missing something important, i.e. why this code has to be in the peers and needs to jump through hoops to satisfy the KFM. ?

I think this is due to the fact that [WX]ComponentPeer are not the only implementation of ComponentPeer interface, we also have NullComponentPeer (or something like that) for lightweight components. and the code you are moving should be called for heavyweight components only.

Oleg.

Oleg,

The requestFocus method is called on the peer of a hw container of the component (which is either the component itself, or the nearest hw parent, as you know). So, I actually have no reason why Roman can't change it like the way he did... Roman split the peer method quite correctly, leaving the peer part to the peer. Don't you agree?

It is probably a little more subtle: The current code doesn't call back to the KFM at all for LW components, because the NullComponentPeer implements requestFocus() as no-op. With my change, we would still call the HW peer, which causes callback into the KFM. However, I am not sure this matters as the KFM seems to reject such requests. If this is an issue this could be solved by checking isLightweight() before calling into the peer.

The getNativeContainer method (called in the code) does return you a heavyweight component. So, you don't need to double check it (it can't have a NullComponentPeer which implements LightweightPeer).

yep, most likely you can workaround this by this check, but I think it will be more safe to perform the refactoring in peer code (at least as the first step).  Unfortunately focus code always was (and now is) rather fragile, so less changes, less regressions.  If you will move the code to java.awt you will have to spend much more time with testing.

I won't argue with the above concern (because the focus code is fragile indeed...). Though your fix looks correct.

Unfortunately I can neither support Anton nor show problems with the fix right now.  I've no seen this code for several years, and I need refresh my memory. Hope I will have time this weekend to re-read the code :)

Regards, Oleg.

So, if you decide to move the code to KFMPeerImpl you may also consider moving KFM.shouldNativelyFocusHeavyweight & KFM.processSynchronousLightweithTransfer methods to the same class (we no longer call them from the native code, so we can avoid using Accessor for them). It should look consistent.

Thanks, Anton.

Another concern is that the requestFocus() is overridden in 1 or 2 other places like WFileDialogPeer to implement no-op. I am not sure what is the issue here or the impact of my change. Any ideas?

file dialog on Windows is implemented using native dialog and we do not support focus requests for it.

Oleg.

Regards, Roman

Roman,

Nevertheless, this was my comment (which I mentioned in the previous post), I think the fix is fine =) (if only Oleg doesn't provide another concern).

Thanks, Anton.

Regards, Roman

Am Montag, den 14.11.2011, 22:35 +0100 schrieb Roman Kennke:

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