[OpenJDK 2D-Dev] [13] RFR: JDK-8221412: lookupPrintServices() does not always update the list of Windows remote printers

[Alexey Ivanov]

Hi,

Please review the fix for jdk 13:

bug: https://bugs.openjdk.java.net/browse/JDK-8221412
webrev: http://cr.openjdk.java.net/~aivanov/8221412/webrev.0/

Description:
The list of printers is not updated in the situation where there are no 
remote printers on the system and later the user adds a remote printer.

Root cause:
JDK-8153732 [1] added a new thread which polls remote printers on the 
system and updates the list if it detects a change. In this case it does 
not update the print services because of this condition:
449 if (prevRemotePrinters != null && prevRemotePrinters.length > 0)
prevRemotePrinters is not null but its length is zero because no remote 
printers were initially present on the system.

Fix:
I removed this if. We have to update the list printers if doCompare() 
returns true. Either prevRemotePrinters or currentRemotePrinters, or 
both can be null; doCompare() handles this situation gracefully after 
JDK-8212202 [2].

The listener called getRemotePrintersNames() twice: in constructor and 
in run() before entering the first sleep. Now it's done only once.

I consolidated the implementation of getAllPrinterNames() and 
getRemotePrintersNames(). They were very similar. The old implementation 
of getRemotePrintersNames() got the list of both local and remote 
printers and then filtered out local ones. The new implementation gets 
the list of remote printers only. So the difference between the two is 
limited to the flags passed to EnumPrinters.

If there are no remote printers, the new version 
getRemotePrintersNames() returns null instead of empty array. As 
mentioned earlier, doCompare() handles this situation.

I'll add the bugid (8221412) to the regression test when fixing 
JDK-8221263 [3]. I'm currently working on it.


Thank you in advance.

Regards,
Alexey

[1] https://bugs.openjdk.java.net/browse/JDK-8153732
[2] https://bugs.openjdk.java.net/browse/JDK-8212202
[3] https://bugs.openjdk.java.net/browse/JDK-8221263