Hi Jay,
We are currently discussing the best strategy for equals/hashcode on
trees of related objects via the CCC. Let us get that settled first
before we go any further...
...jim
On 05/05/2016 12:11 AM, Jayathirth D V wrote:
Hi Jim,
For ComponentColorModel will it be fine if we verify equals() and hashCode()
based on following properties set in Constructor : transferType, signed,
needScaleInit, noUnnorm, nonStdScale?
And for PixelInterleavedSampleModel and BandedSampleModel there are no unique
properties set in constructor and they are calling super() directly and also I
think hashCode() in these subclasses are not needed.
To differentiate discussion between ColorModel and SampleModel, I have started separate
thread for questions related to PixelInterleavedSampleModel and BandedSampleModel with
subject "equals() and hashCode() verification in java.awt.image.ComponentSampleModel
and its subclassses".
Please provide your inputs.
Thanks,
Jay
-----Original Message-----
From: Jim Graham
Sent: Wednesday, May 04, 2016 2:44 AM
To: Phil Race
Cc: 2d-dev@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
Yes, the equals/hashcode chapter in Effective Java includes rules about
ignoring fields that can be calculated from other fields (which applies to most
internal fields). Basically, only things in the constructors tend to be good
candidates for equals/hashcode...
...jim
On 5/3/2016 2:00 PM, Phil Race wrote:
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@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
