Re: Review request for JDK-8075084 JOptionPane.showMessageDialog causes JScrollBar to move

[Alexander Scherbatiy]

On 12/3/2015 11:08 AM, Rajeev Chamyal wrote:

Hello Alexandr,

Thanks for the review.

When we open a JOption dialog from AdjustmentListener the scroll bar 
arrow button is not receiving the mouse release event.

As a result the JScrollBar: scrollTimer is not getting stopped and its 
becoming a recursive call.


   I tried to run the BuggyDialog sample form the issue description 
with the suggested fix.
   I noticed a strange behavior when I press scroll down and click not 
on the JOptionPane OK button but on the close button.
   The scroll bar continues scrolling in this case.

   When a modal dialog is open it blocks others windows. Is it possible 
to check this event and stop the scroll timer in this case?

  Thanks,
  Alexandr.

Regards,

Rajeev Chamyal

*From:*Alexandr Scherbatiy
*Sent:* 02 December 2015 13:56
*To:* Rajeev Chamyal; Sergey Bylokhov; Prasanta Sadhukhan; 
swing-dev@openjdk.java.net
*Subject:* Re: Review request for JDK-8075084 
JOptionPane.showMessageDialog causes JScrollBar to move

On 11/11/2015 7:47 AM, Rajeev Chamyal wrote:

    Hello All,

    Please review the following fix for Jdk9:

      

    Bug:https://bugs.openjdk.java.net/browse/JDK-8075084

    Webrev:http://cr.openjdk.java.net/~rchamyal/8075084/webrev.00/
    <http://cr.openjdk.java.net/%7Erchamyal/8075084/webrev.00/>

    Issue: On running the sample program attached in bug JDK-8075084
    user is expected to see a scrollbar and on clicking the scrollbar
    tracker or scrollbar up/down arrow buttons a JOption dialog should
    come once. The program works fine if scrollbar tracker is clicked
    i.e. JOption dialog comes only once. But on clicking up/down arrow
    buttons of scrollbar the JOption dialog keeps on coming repeatedly.

    Cause: The mouse pressed event of scrollbar arrow buttons calls 
BasicScrollBarUI::scrollByUnit method which creates a property change event and 
calls scroll bar action listener which again calls 
BasicScrollBarUI::scrollByUnit. This is becoming a recursive call and causing 
the scrollbar slider to move repeatedly till it reaches the other end of 
scrollbar.

   If I change the AdjustmentListener to not show the JOptionPane it 
is called only one time.
   What is the reason that showing JOptionPane causes that the 
AdjustmentListener is called one more time?

   Thanks,
   Alexandr.


      

    Fix: Added checks in the BasicScrollBarUI action listener to stop the 
recursion.

      

    Regards,

    Rajeev Chamyal