<AWT Dev> [9] Review request for 8132706 [macosx] Toolkit.getImage() throws NPE for null URL

[Alexander Scherbatiy]

On 4/15/2016 10:55 PM, Sergey Bylokhov wrote:
> On 15.04.16 21:49, Phil Race wrote:
>> I think that even if no exception is thrown we ought to document what
>> happens.
>> Which of course means that we need to be sure that it does happen :-)
>> And the difference depending on SM may be hard to defend.
>> And I am referring to both methods, not just the URL one.
>
> The spec of checkImage/prepareImage both return incorrect status in 
> case of null, seems both should throw NPE also. otherwise they report 
> null as a valid fully loaded image.

    Could you give more details why do you think that 
checkImage/prepareImage methods return incorrect status in case of null 
file path/URL?
    The checkImage just returns a status of an image construction 
"Information on the flags returned by this method can be found with the 
discussion of the ImageObserver interface." and the prepareImage() 
redirects all results to the ImageObserver.

   For example the call of Toolkit.getImage(file) method with path which 
does not point to a file does not lead to the FileNotFoundException. The 
ToolkitImage is created and just wait for the time when it is loaded. 
Only during loading the ImageObserver is called with ABORT info flag.

    The case with null path or URL should follow the same ToolkitImage 
errors handling rule.

   Thanks,
   Alexandr.


>
>>
>> -phil.
>>
>> On 04/15/2016 11:47 AM, Alexander Scherbatiy wrote:
>>> On 15/04/16 22:11, Phil Race wrote:
>>>> And it prints the stack trace ??
>>>>
>>>> This gets even messier.
>>>>
>>>> Is there anything we can do to have sensible specification of
>>>> what happens with null that isn't likely to cause (much) harm ?
>>>
>>>  I see only two options. Do not throw the NPE as it was before and
>>> throw the NPE.
>>>  The second one can break some old applications which do not expect
>>> that the exception can be thrown in this case.
>>>
>>>  If the second option is acceptable probably the Toolkit.getImage()
>>> javadoc can be updated.
>>>
>>>  Thanks,
>>>  Alexandr.
>>>
>>>>
>>>> -phil.
>>>>
>>>>
>>>> On 04/15/2016 11:10 AM, Alexander Scherbatiy wrote:
>>>>> On 15/04/16 20:30, Sergey Bylokhov wrote:
>>>>>> How the object of URLImageSource(null) will be useful? I guess we
>>>>>> will get some unspecified NPE exceptions if will try to call its
>>>>>> methods?
>>>>>   I know nothing about the URLImageSource(null) usefulness but
>>>>> ImageFetcher swallows the NPE during the image loading in the
>>>>> fetchloop() method:
>>>>> -------
>>>>>             try {
>>>>>                 src.doFetch();
>>>>>             } catch (Exception e) {
>>>>>                 System.err.println("Uncaught error fetching image:");
>>>>>                 e.printStackTrace();
>>>>>             }
>>>>> -------
>>>>>
>>>>>   Thanks,
>>>>>   Alexandr.
>>>>>>
>>>>>> On 15.04.16 18:02, Alexander Scherbatiy wrote:
>>>>>>>
>>>>>>> Hello,
>>>>>>>
>>>>>>> Could you review the fix:
>>>>>>>    bug: https://bugs.openjdk.java.net/browse/JDK-8132706
>>>>>>>    webrev: http://cr.openjdk.java.net/~alexsch/8132706/webrev.00
>>>>>>>
>>>>>>>    The fix makes the Toolkit.getDefaultToolkit().getImage(URL)
>>>>>>> return a
>>>>>>> ToolkitImage based on URLImageSource with null url as it was
>>>>>>> before the
>>>>>>> fix JDK-8011059.
>>>>>>>
>>>>>>>    Thanks,
>>>>>>>    Alexandr.
>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
>