RFR: 8252936: Optimize removal of listeners from ExpressionHelper.Generic

[yosbits]

On Thu, 10 Sep 2020 13:41:00 GMT, Kevin Rushforth <kcr at openjdk.org> wrote:

>> I have found that fixing this rudimentary problematic code alleviates your problem.
>> 
>> **This fix will reduce CPU usage by about 1/3 without your changes.**
>> **This fix improves performance in many widespread use cases.**
>> 
>> However, I'm wondering how to report the problem. Should it be handled in this issue? Should I deal with a new issue
>> for a rudimentary issue?
>> @kevinrushforth What should i do?
>> 
>> https://github.com/openjdk/jfx/blob/22d4343fe8563c2931910b98e8f18c6fd4a48f05/modules/javafx.base/src/main/java/com/sun/javafx/collections/ObservableListWrapper.java#L170-L206
>> 
>> Rewritten so that BitSet is not used.
>>  Java
>>     @Override
>>     public boolean removeAll(Collection<?> c) {
>>     	if(this.isEmpty() || c.isEmpty()){
>>     		return false;
>>     	}
>>         beginChange();
>>         boolean removed = false;
>>         for (int i = size()-1; i>=0; i--) {
>>             if (c.contains(get(i))) {
>>                 remove(i);
>>                 removed = true;
>>             }
>>         }
>>         endChange();
>>         return removed;
>>     }
>> 
>>     @Override
>>     public boolean retainAll(Collection<?> c) {
>>     	if(this.isEmpty() || c.isEmpty()){
>>     		return false;
>>     	}
>>         beginChange();
>>         boolean retained = false;
>>         for (int i = size()-1; i>=0; i--) {
>>             if (!c.contains(get(i))) {
>>                 remove(i);
>>                 retained = true;
>>             }
>>         }
>>         endChange();
>>         return retained;
>>     }
>
> @yososs Please file a new JBS issue for this. You will need to prove that your proposed change is functionally
> equivalent (or that any perceived changes are incidental and still conform to the spec). You should also think about
> whether your proposed change needs additional tests.

Because it is such a small correction
Problem from me I feel that it is not easy to register, but I will try to register.

It has passed two existing tests for compatibility:

* gradle base:test
* gradle controls:test

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PR: https://git.openjdk.java.net/jfx/pull/108