<Swing Dev> [11] Review Request: JDK-5076761 : JList.setSelectedValue(null, ...) doesn't do anything

[Sergey Bylokhov]

I doubt that support of null values in the data model is intentional 
because JList is "A component that displays a list of *objects* and 
allows the user to select one or more items."

The null behavior was not specified and work in most cases because some 
of the getXXX methods in ListModel sub-classes and JList have a special 
meaning of null:

JList.getSelectedValue(): Returns {@code null} if there is no selection.
ListModel.getElementAt(int index): In most cases implemented to return 
null if index is incorrect.

Similar method TableModel.getValueAt(int,int) is also usually 
implemented to return null if value is not found or some error occured.

JComboBox.setSelectedItem(): use <code>null</code> to clear the selection
ComboBoxModel.setSelectedItem(): <code>null</code> to clear the selection
ComboBoxModel.getSelectedItem(): <code>null</code> if there is no selection

So I suggest to follow initial intention here, because it is too late to 
add validation of the values.
  - The null value in get() will mean no-selection.
  - The null value passed to set() will clear selection.

On 05/01/2018 02:15, Pankaj Bansal wrote:
> Hi Semyon/Sergey,
> 
> Yes, JList can contain null elements as it can be added to data model. I think this changes a lot in this bug. I think the selection needs to be cleared when the object passed is not present in the list, irrespective of it being null or not. I have made code changes. Please have a look.
> 
> Webrev: http://cr.openjdk.java.net/~pbansal/5076761/webrev.02/
> 
> Regards,
> Pankaj Bansal
> 
> -----Original Message-----
> From: Semyon Sadetsky
> Sent: Friday, January 5, 2018 6:59 AM
> To: Pankaj Bansal; swing-dev at openjdk.java.net
> Subject: Re: <Swing Dev> [11] Review Request: JDK-5076761 : JList.setSelectedValue(null, ...) doesn't do anything
> 
> Hi Pankaj,
> 
> Can JList contain null value?
> 
> --Semyon
> 
> 
> On 01/02/2018 11:26 PM, Pankaj Bansal wrote:
>> Hi Sergey,
>>
>> Thanks for the review.
>>
>> I have made the suggested changes. Please have a look.
>> webrev: http://cr.openjdk.java.net/~pbansal/5076761/webrev.01/
>>
>> Regards,
>> Pankaj Bansal
>>
>>
>> -----Original Message-----
>> From: Sergey Bylokhov
>> Sent: Wednesday, January 3, 2018 3:31 AM
>> To: Pankaj Bansal; swing-dev at openjdk.java.net; Prasanta Sadhukhan
>> Subject: Re: [11] Review Request: JDK-5076761 :
>> JList.setSelectedValue(null, ...) doesn't do anything
>>
>> Hi, Pankaj.
>> The fix looks fine, but I suggest to update the spec as well and describe the behavior if "null" value is passed.
>>
>> On 02/01/2018 02:07, Pankaj Bansal wrote:
>>> Hi All,
>>>
>>> Please review the fix for JDK 11.
>>>
>>> Bug:
>>>
>>> https://bugs.openjdk.java.net/browse/JDK-5076761
>>>
>>> Webrev:
>>>
>>> http://cr.openjdk.java.net/~pbansal/5076761/webrev.00/
>>>
>>> Issue:
>>>
>>> When setSelectedValue is called on JList with null object, it should
>>> clear all selection. But it is not doing anything.
>>>
>>> Fix:
>>>
>>> In setSelectedValue if the object is null, the setSelectedIndex is
>>> called with -1. but this does not clear the selection. We should be
>>> calling clearSelection instead of SetSelectedIndex.
>>>
>>> Regards,
>>>
>>> Pankaj Bansal
>>>
>>
>> --
>> Best regards, Sergey.
> 


-- 
Best regards, Sergey.