Re: [jdk20] RFR: 8301989: new javax.swing.text.DefaultCaret().setBlinkRate(N) results in NPE [v2]

[Phil Race]

On Wed, 8 Feb 2023 18:12:40 GMT, Alexander Zuev <kiz...@openjdk.org> wrote:

>> So if I go back and look at the code before your previous fix, there was no 
>> check,
>> so the timer is created and then I'd expect applies when the caret is 
>> installed on a component.
>> Here that behaviour is changed, so that if we create a caret, then call 
>> setBlinkRate(), and then install()
>> then the blink rate appears to be ignored whereas before 4512626 it was 
>> applied.
>
>> if we create a caret, then call setBlinkRate(), and then install()
>> then the blink rate appears to be ignored whereas before 4512626 it was 
>> applied.
> 
> Ok, if the text component is already visible and editable and focused and we 
> install the new caret then the blink rate will not have an effect until the 
> focus is lost and regained or until it became non-editable - and i think that 
> was close to what we had before and there is a bug to investigate and 
> optimize such corner case. In all other cases the code works fine. The value 
> set is being preserved and will be reactivated when any of the methods such 
> as focusGained or when the component installUI is called - if the cursor is 
> set before component becomes visible - will cause to re-evaluate the blink 
> rate and the stored value set by user will take place.

Suppose I have this code

Caret c = new DefaultCaret()
c.setBlinkRate(50);
c.install(editableJComponent);

BEFORE 4512626 the JDK code looked like this

     if (rate != 0) {
            if (flasher == null) {
                flasher = new Timer(rate, handler);
            }
            flasher.setDelay(rate);
        }


With your fix it looks like this

     if (rate != 0) {
            if (component != null && component.isEditable()) {
               if (flasher == null) {
                   flasher = new Timer(rate, handler);
               }
             }
        }


So with my sample application code there's a change that my blink rate is 
completely lost.

-------------

PR: https://git.openjdk.org/jdk20/pull/122