<Swing Dev> [11] Review Request: JDK-6481195 ListSelectionListener indicates events on model.addElement after model.clear()

[Sergey Bylokhov]

On 02/02/2018 23:05, Pankaj Bansal wrote:
> Hi Sergey,
> 
>>> Can somebody clarify why -1/-1 is incorrect? lead/anchor values are not min/max selected element, it can be any elements: selected/unselected and is not necessary >>first/last selected element.
> 
> According to API description of getAnchor/LeadSelectionIndex, anchor/lead return the first/second index of most recent call to setSelectionInterval(), addSelectionInterval() or removeSelectionInterval().

This means that if an application will call any of these methods then 
the anchor/lead will be taken from the latest call. For example if the 
application will select a few intervals then the anchor/lead will be 
based on the latest interval. But if selection model will be 
modified(for example via 
insertIndexInterval/setAnchorSelectionIndex/setLeadSelectionIndex/removeIndexInterval/etc)after 
that it does not mean that anchor/lead will be preserved.

> 
> Now in following example, most recent call to one of the three API was with 0/0 as first/second index as addSelectionInterval is called from setSelectedIndices. So the anchor/lead should be 0/0 according to the API description. So -1/-1 value is wrong.
> list.setSelectedIndices(new int[] {1, 0}); // selection is [0 ,1] lead/anchor = 0/0
> model.removeElementAt(0); // selection is [0] lead/anchor = 0/0 (before fix), -1/-1(after fix)
> 
> But as I pointed out with next example, removeIndexInterval  sets wrong anchor/lead value for all indices even before the fix.  removeIndexInterval handles the 0 index specially and maintains correct value of anchor/lead. I have just removed the code for special handling of 0 index.
> list.setSelectedIndices(new int[] {2, 1}); // selection is [1 ,2] lead/anchor = 1/1
> model.removeElementAt(1); // selection is [1] lead/anchor = 0/0  (before the fix. I have verified it. It should be 1/1 according to API description)
> 
> I also feel that, if we go by API description, only setSelectionInterval(), addSelectionInterval() or removeSelectionInterval() should change the achor/lead values. But there are other APIs lile insertIndexInterval, removeIndexInterval which change anchor/lead. Also there are set functions for anchor/lead, which should not be there.
> 
> Regards,
> Pankaj Bansal
> 
> -----Original Message-----
> From: Sergey Bylokhov
> Sent: Saturday, February 3, 2018 3:25 AM
> To: Pankaj Bansal; Semyon Sadetsky; swing-dev at openjdk.java.net
> Subject: Re: <Swing Dev> [11] Review Request: JDK-6481195 ListSelectionListener indicates events on model.addElement after model.clear()
> 
> On 01/02/2018 23:25, Pankaj Bansal wrote:
>> Ok, I got your point. In the example you gave, as addSelectionInterval
>> was called from setSelectedIndices with 0 at last, the lead/anchor
>> should be 0/0 not -1/-1.
> 
> Can somebody clarify why -1/-1 is incorrect? lead/anchor values are not min/max selected element, it can be any elements: selected/unselected and is not necessary first/last selected element.
> 
> 
> --
> Best regards, Sergey.
> 


-- 
Best regards, Sergey.