<Swing Dev> <AWT Dev> Please review fix for 7177111 : Jcomponent.AccessibleJComponent.AddPropertyListeners adds exponential listeners

[Anthony Petrov]

Looks fine.

--
best regards,
Anthony

On 11/09/12 01:51, Pete Brunet wrote:
> Hi Everyone, Please review the following fix planned for 7u12. It will
> also go into 8 under 7179482.
>
> Problem:
> When an AT (Assistive Technology) accesses a Java application with
> several nested frames, too many property change listeners are added
> resulting in a severe performance impact for an AT user.
>
> The issue is due to the fact that there is an accessibleContainerHandler
> field in both javax.swing.JComponent.AccessibleJComponent and its
> superclass, java.awt.Container.AccessibleAWTContainer. When an AT calls
> JComponent.AccessibleJComponent.addPropertyChangeListener a handler is
> new'd and assigned to its accessibleContainerHandler field and then the
> same method in the superclass is called and it also new's and assigns a
> handler to its accessibleContainerHandler field. Since there are two
> handlers, when a child component is later added there are two callbacks
> and for each one the AT will call addPropertyChangeListener, each of
> which will add two handlers. For deeply nested trees the explosion of
> events has a negative impact on performance, i.e. there are 2 handlers
> added for the first level, 4 for the second level, 8 for the third
> level, etc.
>
> Solution:
> Remove protected field
> javax.swing.JComponent.AccessibleJComponent.accessibleContainerHandler.
> Instead, the protected field of the same name in
> java.awt.Container.AWTAccessibleContainer will be used.
>
> Webrev: http://cr.openjdk.java.net/~ptbrunet/7177111/webrev.03/
> Bug:
> http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7177111
> http://monaco.us.oracle.com/detail.jsf?cr=7177111
> CCC: http://ccc.us.oracle.com/7177111