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

[Jayathirth D V]

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
>>
>>
>>
>