[OpenJDK 2D-Dev] Review Request for JDK-8153943 : In java.awt.image package some of the classes are missing hashCode() or equals() method

[Phil Race]

On 04/26/2016 04:10 PM, Jim Graham wrote:
> The ComponentColorModel implementation is a meaningless wrapper around 
> super.equals/hashCode().  Why does it not test CCM-specific fields?

It should although this looks like it is more than just running through
all the fields and testing them for equality.
eg it looks like "initScale()" should be called if necessary before
determining equality and the field "needScaleInit" is not one that
has to be directly included in the equality comparison.

-phil.



>
> The ComponentSampleModel.hashCode() method should be upgraded based on 
> the recommendations in Effective Java like the other methods here.
>
> PixelInterleavedSampleModel and BandedSampleModel also have a 
> meaningless override of super.equals/hashCode().
>
> And all of these classes suffer from casting to the specific type 
> before verifying its class as I mentioned in the ICM.equals() review...
>
>             ...jim
>
> On 4/25/16 2:31 AM, Jayathirth D V wrote:
>> Hi Jim,
>>
>> I have made changes to include check for class equality in base class 
>> and use super.equals() from subclasses.
>> Please find updated webrev for review :
>> http://cr.openjdk.java.net/~jdv/8153943/webrev.02/
>>
>> Change related to ColorModel is present in JDK-7107905 review.
>>
>> Thanks,
>> Jay
>>
>> -----Original Message-----
>> From: Jim Graham
>> Sent: Saturday, April 23, 2016 7:30 AM
>> To: Phil Race; Jayathirth D V
>> Cc: 2d-dev at openjdk.java.net
>> Subject: Re: [OpenJDK 2D-Dev] Review Request for JDK-8153943 : In 
>> java.awt.image package some of the classes are missing hashCode() or 
>> equals() method
>>
>> This is actually a pretty nasty issue that Joe Darcy also brought up 
>> in the CCC review.
>>
>> In order to have symmetric testing of .equals(), we pretty much have 
>> to enforce this test at all levels, including in the original
>> ColorModels.equals() method.  If we don't enforce this in 
>> CM.equals(), then we could run ccm.equals(othercm) and it would 
>> return false because the class is wrong, but turning it around and 
>> testing
>> othercm.equals(ccm) would succeed because it doesn't enforce the 
>> class equality.
>>
>> So, I'd recommend that CM.equals() tests getClass() == getClass() at 
>> the base level and then all others will use super.equals() and get 
>> the same protection.  It means you can't have a subclass of CCM be 
>> "equals" to a different subclass of CCM, but that's an unfortunate 
>> issue with equals needing to honor symmetry...  :(
>>
>>             ...jim
>>
>> On 4/20/2016 10:17 AM, Phil Race wrote:
>>> Hi, You removed the following test in CCM.java : 2941 if
>>> (obj.getClass() != getClass()) {
>>> 2942 return false;
>>>
>>> 2943         }
>>>
>>> What this means is that before your change an instance of a subclass
>>> of CCM would never be equals() to any direct instantiatation of CCM
>>> but after your change it can be. I suspect the condition was there 
>>> on purpose.
>>>
>>> -phil.
>>>
>>> On 04/20/2016 05:45 AM, Jayathirth D V wrote:
>>>>
>>>> Hi,
>>>>
>>>>
>>>>
>>>> _Please review the following fix in JDK9:_
>>>>
>>>>
>>>>
>>>> Bug : https://bugs.openjdk.java.net/browse/JDK-8153943
>>>>
>>>>
>>>>
>>>> This is subtask of https://bugs.openjdk.java.net/browse/JDK-6588409
>>>>
>>>>
>>>>
>>>> Webrev : http://cr.openjdk.java.net/~jdv/8153943/webrev.00/
>>>> <http://cr.openjdk.java.net/%7Ejdv/8153943/webrev.00/>
>>>>
>>>>
>>>>
>>>> Issue : Some of the java.awt.image classes are missing either
>>>> equals() or hashCode() method.
>>>>
>>>>
>>>>
>>>> Solution : Add missing equals() or hashCode() methods.
>>>>
>>>>
>>>>
>>>> Thanks,
>>>>
>>>> Jay
>>>>
>>>>
>>>>
>>>