Hello Jason and everyone else,
here is my webrev that my colleague published
http://cr.openjdk.java.net/~clanger/webrevs/6421373.0/
<http://cr.openjdk.java.net/%7Eclanger/webrevs/6421373.0/>
Can you please review it and let me know if I should change anything?
Currently I am OOO, but I will do the changes in March.
Kind regards,
Vlad
Get Outlook for iOS <https://aka.ms/o0ukef>
------------------------------------------------------------------------
*From:* Jason Mehrens <jason_mehr...@hotmail.com>
*Sent:* Tuesday, February 11, 2020 9:13:41 PM
*To:* Volodin, Vladislav <vladislav.volo...@sap.com>
*Cc:* swing-dev@openjdk.java.net <swing-dev@openjdk.java.net>
*Subject:* Re: <Swing Dev> Remove System.out.println from
ImageIcon.loadImage
Vlad,
Yea that looks good.
Jason
________________________________________
From: Volodin, Vladislav <vladislav.volo...@sap.com>
Sent: Wednesday, February 5, 2020 9:59 AM
To: Jason Mehrens
Cc: swing-dev@openjdk.java.net
Subject: RE: <Swing Dev> Remove System.out.println from
ImageIcon.loadImage
Hi Jason,
thank you for your advice. I have changed my code, now it simulates
the behavior of the interrupted thread. Can you please check my patch?
I don't have the "bug" ticket, so in my test case "@bug JDK-123456"
should be adjusted.
I will appreciate if you and somebody else can review my patch and
submit it to JDK.
Thanks,
Vlad
-----Original Message-----
From: Jason Mehrens <jason_mehr...@hotmail.com>
Sent: Mittwoch, 29. Januar 2020 17:55
To: Volodin, Vladislav <vladislav.volo...@sap.com>
Cc: swing-dev@openjdk.java.net
Subject: Re: <Swing Dev> Remove System.out.println from
ImageIcon.loadImage
1. Agreed.
2. I was just pulling from the jdk8 source (because I'm lazy) to
express the idea. Feel free to adjust.
3. Reasserting in the finally ensure we are not forcefully setting the
interrupted status on the current thread and calling 'statusID' and
'removeImage'. It also ensures that the interrupt is set even if an
unexpected exception is thrown. Reasserting at the end of 'e1' and
never in 'e2' should work too.
The main issue that I'm trying to convey to you is that your test is
incomplete in that it does check that the interrupt was swallowed.
Swallowing interrupts is bad practice. Reasserting in e2 only means
that we swallow interrupts from e1.
Change your test to this and retest:
===
public static void main(String[] args) throws Exception {
Toolkit ignoreToolkit = Toolkit.getDefaultToolkit();
Thread.currentThread().interrupt();
ImageIcon iconInterrupt = new ImageIcon(EMPTY_GIF);
if (iconInterrupt.getImageLoadStatus() != MediaTracker.COMPLETE) {
throw new RuntimeException("Couldn't load GIF from bytes
after interruption");
}
if (!Thread.currentThread().isInterrupted()) {
throw new RuntimeException("Interrupt was swallowed");
}
}
}
===
________________________________________
From: Volodin, Vladislav <vladislav.volo...@sap.com>
Sent: Wednesday, January 29, 2020 9:52 AM
To: Jason Mehrens
Cc: swing-dev@openjdk.java.net
Subject: RE: <Swing Dev> Remove System.out.println from
ImageIcon.loadImage
Hi Jason,
I have few questions:
1. The second assignment is probably redundant:
} catch (InterruptedException e1) {
wasInterrupted = true; // line #2, see comment below
try {
mTracker.waitForID(id, 0);
} catch (InterruptedException e2) {
loadStatus = MediaTracker.ABORTED;
wasInterrupted = true; // <-- this is redundant,
because of the line #2
}
} finally {
2. I think the first call of "addImage" is not necessary:
boolean wasInterrupted = false;
mTracker.addImage(image, id); // maybe I should remove this, because
of another comment down below.
try {
loadStatus = 0;
mTracker.addImage(image, id); // because of that
May I also ask you a question?
What is the purpose of interrupting the current thread in the finally
block, instead of doing it in the second catch block (where e2 is
created)? I assume that since we were able to handle the exception
properly, and plus the entire block is in the synchronization area, in
theory we have only one importer at the time.
Kind regards,
Vlad
-----Original Message-----
From: Jason Mehrens <jason_mehr...@hotmail.com>
Sent: Mittwoch, 29. Januar 2020 16:35
To: Volodin, Vladislav <vladislav.volo...@sap.com>
Cc: swing-dev@openjdk.java.net
Subject: Re: <Swing Dev> Remove System.out.println from
ImageIcon.loadImage
Bug in that last version:
Thread.currentThread().isInterrupted(); ->
Thread.currentThread().interrupt();
===
protected void loadImage(Image image) {
MediaTracker mTracker = getTracker();
synchronized (mTracker) {
int id = getNextID();
boolean wasInterrupted = false;
mTracker.addImage(image, id);
try {
loadStatus = 0;
mTracker.addImage(image, id);
mTracker.waitForID(id, 0);
} catch (InterruptedException e1) {
wasInterrupted = true;
try {
mTracker.waitForID(id, 0);
} catch (InterruptedException e2) {
loadStatus = MediaTracker.ABORTED;
wasInterrupted = true;
}
} finally {
if (loadStatus == 0) {
loadStatus =
mTracker.statusID(id, false);
}
mTracker.removeImage(image, id);
if (wasInterrupted) {
Thread.currentThread().interrupt();
}
}
}
}
===
________________________________________
From: swing-dev <swing-dev-boun...@openjdk.java.net> on behalf of
Jason Mehrens <jason_mehr...@hotmail.com>
Sent: Wednesday, January 29, 2020 9:33 AM
To: Volodin, Vladislav
Cc: swing-dev@openjdk.java.net
Subject: Re: <Swing Dev> Remove System.out.println from
ImageIcon.loadImage
A shorter version is just to reassert at the end of catch e1. It is
safer to just reassert as the last statement in the finally.
===
protected void loadImage(Image image) {
MediaTracker mTracker = getTracker();
synchronized (mTracker) {
int id = getNextID();
boolean wasInterrupted = false;
mTracker.addImage(image, id);
try {
loadStatus = 0;
mTracker.addImage(image, id);
mTracker.waitForID(id, 0);
} catch (InterruptedException e1) {
wasInterrupted = true;
try {
mTracker.waitForID(id, 0);
} catch (InterruptedException e2) {
loadStatus = MediaTracker.ABORTED;
}
} finally {
if (loadStatus == 0) {
loadStatus =
mTracker.statusID(id, false);
}
mTracker.removeImage(image, id);
if (wasInterrupted) {
Thread.currentThread().isInterrupted();
}
}
}
}
===
Jason
________________________________________
From: Volodin, Vladislav <vladislav.volo...@sap.com>
Sent: Tuesday, January 28, 2020 4:02 PM
To: Jason Mehrens
Cc: swing-dev@openjdk.java.net
Subject: Re: <Swing Dev> Remove System.out.println from
ImageIcon.loadImage
This is a valid point, because I wasn’t sure that when the thread is
interrupted, I handled the first exception, and my thought was that
all other ‘wait’ calls (maybe in other threads) should get the same
exception as well.
And since I handled this exceptional case, I am restoring the
interrupted status in case if I don’t know how to handle this
exception the second time.
} catch (InterruptedException e1) {
try {
mTracker.waitForID(id, 0);
} catch (InterruptedException e2) {
loadStatus = MediaTracker.ABORTED;
Thread.currentThread().interrupt();
}
If I restore the interrupted status BEFORE waitForID call, then this
thread will immoderately fail. Should I restore it AFTER, e.g.
} catch (InterruptedException e1) {
try {
mTracker.waitForID(id, 0);
Thread.currentThread().interrupt(); // <— Here?
} catch (InterruptedException e2) {
loadStatus = MediaTracker.ABORTED;
Thread.currentThread().interrupt();
}
Thanks,
Vlad
Sent from myPad
> On 28. Jan 2020, at 22:27, Jason Mehrens <jason_mehr...@hotmail.com>
wrote:
>
> I see. Well I would have to do some more digging and testing to
make myself more knowledgeable on MediaTracker.
>
> Then the only bug in your current code is that you are not
reasserting interrupted status of the current thread in the case e1 is
raised and e2 is not. It is usually best to reassert the interrupted
state at the end of the method.
>
> Jason
>
> ________________________________________
> From: Volodin, Vladislav <vladislav.volo...@sap.com>
> Sent: Tuesday, January 28, 2020 2:54 PM
> To: Jason Mehrens
> Cc: swing-dev@openjdk.java.net
> Subject: Re: <Swing Dev> Remove System.out.println from
ImageIcon.loadImage
>
> Hi Jason,
>
> I am not sure about the loop, because I don’t know if we can trust
results from mTracker.statusID at the moment when an exceptional case
occurs. For example, I was experimenting with the code and found out
that the MediaTracker can spawn a thread to load the image, or might
use the current thread, and the ABORTED state is never returned (I
don’t even know how to raise this state). That is why I don’t even
know if your loop will ever stop.
>
> In my solution, I give the second chance only, and in case if the
execution was interrupted the second time, I explicitly assign the
ABORTED state to loadStatus. If the user wants to load this image once
again, he can create ImageIcon again (or even do this in a loop), or
reinitialize it with a single method (I don’t remember its name).
>
> What do you think?
>
> Kind regards,
> Vlad
>
> Sent from myPad
>
>> On 28. Jan 2020, at 21:34, Jason Mehrens <jason_mehr...@hotmail.com>
wrote:
>>
>> Vlad,
>>
>> I assume you would want to wait in a loop and reassert the interrupt
at the end.
>>
>> ===
>> protected void loadImage(Image image) {
>> MediaTracker mTracker = getTracker();
>> synchronized(mTracker) {
>> int id = getNextID();
>>
>> mTracker.addImage(image, id);
>> boolean wasInterrupted = false;
>> try {
>> do {
>> try {
>> mTracker.waitForID(id, 0);
>> } catch (InterruptedException e) {
>> wasInterrupted = true;
>> }
>> loadStatus = mTracker.statusID(id, false);
>> } while (loadStatus == MediaTracker.LOADING);
>> mTracker.removeImage(image, id);
>>
>> width = image.getWidth(imageObserver);
>> height = image.getHeight(imageObserver);
>> } finally {
>> if (wasInterrupted) {
>> Thread.currentThread().interrupt();
>> }
>> }
>> }
>> }
>> ===
>>
>> Jason
>> ________________________________________
>> From: swing-dev <swing-dev-boun...@openjdk.java.net> on behalf of
Volodin, Vladislav <vladislav.volo...@sap.com>
>> Sent: Monday, January 27, 2020 11:11 AM
>> To: Sergey Bylokhov
>> Cc: swing-dev@openjdk.java.net
>> Subject: Re: <Swing Dev> Remove System.out.println from
ImageIcon.loadImage
>>
>> Hello Sergey, and others,
>>
>> here is the patch (made with "git diff") in the attachment. I have
read that sometimes the attachments are lost. So here is my version
with few comments regarding my code. I decided to use your approach
with a small improvement. There is an excerpt of my patch.
>>
>> The idea is pretty simple:
>> 1. I create an empty gif 1x1;
>> 2. Initialize DefaultToolkit (I plan to interrupt the main thread,
and if I do not initialize the toolkit in advance, my test will fail
at the beginning
>> 3. Interrupt the main thread
>> 4. Try to load the icon:
>>
>> import javax.swing.*;
>> import java.awt.*;
>>
>> public class imageIconInterrupted {
>> static byte[] EMPTY_GIF = new byte[]{
>> (byte) 0x47, (byte) 0x49, (byte) 0x46, (byte) 0x38, (byte)
0x39, (byte) 0x61, (byte) 0x01, (byte) 0x00,
>> (byte) 0x01, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte)
0x00, (byte) 0x21, (byte) 0xF9, (byte) 0x04,
>> (byte) 0x01, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte)
0x00, (byte) 0x2C, (byte) 0x00, (byte) 0x00,
>> (byte) 0x00, (byte) 0x00, (byte) 0x01, (byte) 0x00, (byte)
0x01, (byte) 0x00, (byte) 0x00, (byte) 0x02
>> };
>>
>> public static void main(String[] args) throws Exception {
>> Toolkit ignoreToolkit = Toolkit.getDefaultToolkit();
>>
>> Thread.currentThread().interrupt();
>> ImageIcon iconInterrupt = new ImageIcon(EMPTY_GIF);
>> if (iconInterrupt.getImageLoadStatus() != MediaTracker.COMPLETE) {
>> throw new RuntimeException("Couldn't load GIF from bytes
after interruption");
>> }
>> }
>> }
>>
>> The code of loadImage I have changed as follows:
>> 1. I clear loadStatus for "finally" part;
>> 2. Check the interruption according to your comments;
>> 3. Change the status to ABORTED, if the interruption happened again
(this part I cannot test, because I cannot properly interrupt the
thread whenever I want. Multithreading is quite fragile there :( )
>> 4. update the status "interrupted" again;
>> 5. and then - finally block.
>>
>> protected void loadImage(Image image) {
>> ...
>> try {
>> loadStatus = 0;
>> mTracker.addImage(image, id);
>> mTracker.waitForID(id, 0);
>> } catch (InterruptedException e1) {
>> try {
>> mTracker.waitForID(id, 0);
>> } catch (InterruptedException e2) {
>> loadStatus = MediaTracker.ABORTED;
>> Thread.currentThread().interrupt();
>> }
>> } finally {
>> if (loadStatus == 0) {
>> loadStatus = mTracker.statusID(id, false);
>> }
>> mTracker.removeImage(image, id);
>> }
>>
>> P.S. if you think that my patch sounds fine, I will find a sponsor
for the bug report and the patch preparation, so you can review it later.
>> After the second attempt, my EMPTY_GIF was loaded successfully. The
ABORTED part it seems that I don't know if it has ever worked. My
patch (in the attachment) checks also the state ERROR for the URL that
doesn't exist. Something like:
>>
>> ImageIcon iconNotExist = new ImageIcon(new
URL("http://doesnt.exist.anywhere/1.gif";)); // I am not sure if I
spelled this URL grammatically correct
>> if (iconNotExist.getImageLoadStatus() != MediaTracker.ERRORED) {
>> throw new RuntimeException("Got unexpected status from
non-existing GIF");
>> }
>>
>> Thanks to everyone.
>>
>> Kind regards,
>> Vlad
>>
>> -----Original Message-----
>> From: Sergey Bylokhov <sergey.bylok...@oracle.com>
>> Sent: Dienstag, 21. Januar 2020 22:26
>> To: Volodin, Vladislav <vladislav.volo...@sap.com>
>> Cc: Jason Mehrens <jason_mehr...@hotmail.com>;
swing-dev@openjdk.java.net
>> Subject: Re: <Swing Dev> Remove System.out.println from
ImageIcon.loadImage
>>
>>>> On 1/21/20 1:14 pm, Volodin, Vladislav wrote:
>>> Hi all,
>>>
>>> If I am not mistaken, this method is called from the constructor
and other methods. How long should we try loading the icon using the
unmanaged (by any thread pool, but I am not sure about this statement)
thread?
>>>
>>> We don’t even have the flag “interrupted”. So technically this icon
has to be loaded.
>>
>> I think it is necessary to save the "interrupted" state in the catch
>> block and try to call waitForID() again. It will be necessary to set
>> "interrupted" flag for the Thread after that(when the waitForID will
>> return without exception).
>>
>>
>>> Sent from myFone
>>>
>>>>> On 21. Jan 2020, at 21:55, Sergey Bylokhov
<sergey.bylok...@oracle.com> wrote:
>>>>
>>>> On 1/21/20 12:26 pm, Jason Mehrens wrote:
>>>>> +1 for Sergey suggestion.
>>>>
>>>> Or probably we need to try to load the image again because of the
spec of the method state this:
>>>> "Loads the image, returning only when the image is loaded."
>>>>
>>>>> ________________________________________
>>>>> From: Sergey Bylokhov <sergey.bylok...@oracle.com>
>>>>> Sent: Sunday, January 19, 2020 9:31 PM
>>>>> To: Volodin, Vladislav; Jason Mehrens
>>>>> Cc: swing-dev@openjdk.java.net
>>>>> Subject: Re: <Swing Dev> Remove System.out.println from
ImageIcon.loadImage
>>>>> I guess there are no objections, probably the best way to fix
>>>>> it is to drop the System.out.println and set interrupted flag.
>>>>> On 1/16/20 7:05 am, Volodin, Vladislav wrote:
>>>>>> If people in this distribution list agree, I can start working
on a simple fix and either remove the logging (System.out.println), or
replace it with PlatformLogger. I guess the second solution sounds
better, but I don't know what is the better way to write a test-case
for it.
>>>>> --
>>>>> Best regards, Sergey.
>>>>
>>>>
>>>> --
>>>> Best regards, Sergey.
>>
>>
>> --
>> Best regards, Sergey.
![http://doesnt.exist.anywhere/1.gif"](http://doesnt.exist.anywhere/1.gif"){kind=link}