On Wed, 25 Nov 2020 00:15:11 GMT, Sergey Bylokhov <s...@openjdk.org> wrote:
> Here is a fix for one of the annoying bug, which causes random test failures
> in the CI.
>
> We have a method Robot.waitForIdle(), which supposed to wait until the java
> and the native queue stabilized. The common use case is to click on the
> button or show the window, and call waitForIdle() which will wait until the
> native event will be dispatched by the X11/Windows/macOS as well as followed
> Java event(paint/focus/etc event) will be dispatched to the EDT.
>
> Currently, it is implemented in this way:
> 1. Flush the EventQueue, so all old events will be posted to EDT.
> 2. Flush the native event queue, by posting the native event.
> 3. Flush the EDT, by posting a java event.
> 4. If some events(unrelated to waitForIdle machinery) were dispatched on
> steps 2. or 3. then repeat since step 1.
>
> It is implemented that they because the native events caused by the OS
> usually generate the java events, and the java events may generate native
> events. So we have to wait for both queues (java/native).
>
> But it has the next disadvantages:
> - It is implemented as a busy loop, which does not give a chance for the
> application to proceed further since it blocks 3 threads EDT/native toolkit
> thread like appkit/main thread.
> - It throws the InfiniteLoop exception if the number of attempts is bigger
> than 20. And this limitation is too small because some tests generate much
> more events during startup.
> - Note that the timeout value for the realSync method is 10 seconds, and it
> was assumed that this method will not be executed longer, but it uses this
> timeout for all events flushing which can lead up to 600 seconds (20 iters *
> 3 calls * 10 seconds).
>
>
> The fix:
> - Add a small delay to the method, so the app can do something useful when
> waitForIdle() is called
> - The timeout=10 second is taken care of, we calculate the "end" time and
> exits if it is exceeded
> - The maximum number of attempts is increased to 100 and InfiniteLoop is
> removed.
>
> Note that I have made one additional change to the new realSync
> implementation. At the beginning of the method I call:
> EventQueue.invokeAndWait(() -> {/*dummy implementation*/});
> It is needed to be sure that we flush the first event on EDT even if we spend
> more time than 10 seconds.
This pull request has now been integrated.
Changeset: 973255c4
Author: Sergey Bylokhov <s...@openjdk.org>
URL: https://git.openjdk.java.net/jdk/commit/973255c4
Stats: 242 lines in 9 files changed: 192 ins; 20 del; 30 mod
8196100: javax/swing/text/JTextComponent/5074573/bug5074573.java fails
Reviewed-by: kizune
-------------
PR: https://git.openjdk.java.net/jdk/pull/1424
