<Swing Dev> [12] RFR JDK-8192888: AllSwingComponentsBaselineTest fails with NullPointerException for NimbusLookAndFeel

[Prasanta Sadhukhan]

Hi Sergey,

I saw that in *ButtonUI class for all lookandfeels, we are caching the 
ui object and returning
AquaButtonUI - createUI() caches buttonUI via 
RecyclableSingletonFromDefaultConstructor<AquaButtonUI>(AquaButtonUI.class) 
which is returned everytime.
MotifButtonUI - createUI() caches in the same way as this fix
BasicButtonUI - createUI() caches in the same way as this fix
MetalButtonUI - createUI() caches in the same way as this fix
WindowsButtonUI - createUI() caches in the same way as this fix

so I guess we should do the same for SynthButtonUI too as has been done 
in webrev.2 below.

Regards
Prasanta
On 15-Sep-18 5:39 AM, Sergey Bylokhov wrote:
> Hi, Prasanta.
> I have checked some other UI delegates(in Synth and others L&F), and 
> found that sometimes result of createUI is cached, but sometimes not. 
> Can you please describe some logic when to use or not to use cache?
>
> On 13/09/2018 00:20, Prasanta Sadhukhan wrote:
>> Yes. So, it seems getBaseline() gets null style because of this reason:
>>
>> When JButton is created, it calls JButton.updateUI() which calls 
>> UIManager.updateUI() which calls UIDefaults.getUI and it calls 
>> SynthButtonUI.createUI() which created a new SynthButtonUI everytime. 
>> SynthButtonUI.installDefaults() updates the style for this 
>> SynthButtonUI object.
>>
>> But in testcase, we again call UIManager.getUI(JButton) which again 
>> triggers the same flow culminating in SynthButtonUI.createUI which 
>> creates a new SynthButtonUI object with null style.
>>
>> Like in other look and feel ButtonUI for ex, MetalButtonUI, 
>> WindowsButtonUI, createUI should be updated not to create a new 
>> object everytime but to cache the object in appcontext and retrieves 
>> that instead of recreating everytime.
>> Modified webrev: 
>> http://cr.openjdk.java.net/~psadhukhan/8192888/webrev.2/
>>
>> Regards
>> Prasanta
>> On 13-Sep-18 1:18 AM, Sergey Bylokhov wrote:
>>> On 11/09/2018 22:03, Prasanta Sadhukhan wrote:
>>>>> Why SynthLookAndFeel.updateStyle() which is called in 
>>>>> SynthButtonUI.updateStyle(AbstractButton b) did not update the 
>>>>> context which is passed to it? Is it possible that 
>>>>> SynthButtonUI.installDefaults() was not called before getBaseline()?
>>>>>
>>>> SynthButtonUI.updateStyle() called from 
>>>> SynthButtonUI.installDefaults() creates a new context whereas in 
>>>> getBaseline() we again calls getContext() in l207 which creates a 
>>>> new SynthContext, so the style was not updated to the context 
>>>> currently being queried in getBaseline()
>>>
>>> SynthButtonUI.updateStyle() creates a new context and at the same 
>>> time updates the "SynthStyle.style", so the new SynthContext created 
>>> in getBaseline() should use non-null "SynthStyle.style", no?
>>>
>>>
>>
>
>