[OpenJDK 2D-Dev] RFR: 8263311: Watch registry changes for remote printers update instead of polling

Prasanta Sadhukhan psadhukhan at openjdk.java.net
Fri Mar 12 12:42:07 UTC 2021


On Fri, 12 Mar 2021 12:30:13 GMT, Alexey Ivanov <aivanov at openjdk.org> wrote:

>> I can understand that as a user, you cannot /shouldn't change the name of a remote network printer but a network admin can change the name, so shouldn't we get notification on that name change when this method gets called after the name change? or would it be notified as a new printer in that case? Then what will happen to the old stale printer in the registry?
>
> You can't. Try it yourself. The printer connection is per-user, after all it's stored under HKCU.
> 
> Windows displays the name of remote printers as “Generic / Text Only on 192.168.1.18”: _the name of the printer_ and _the remote host_.
> 
> If you open the *Printer Properties* dialog of a remote printer and edit its name, you change the name of the printer on the remote host which shares it. It changes *absolutely nothing* on the local system.
> 
>> shouldn't we get notification on that name change when this method gets called after the name change?
> 
> Yes, we should. But we cannot.
> 
> For Windows, nothing has changed on the local system, it's the remote system that has been changed.
> 
>> or would it be notified as a new printer in that case?
> 
> No, it wouldn't _because nothing has changed on the local system_.
> 
>> Then what will happen to the old stale printer in the registry?
> 
> Nothing, again. It just stays there but Windows reports an error if you try to open its Printer Properties, Windows reports an error if you try to print to it. I tried printing with Java and Notepad: the behaviour is the same. The difference is that Notepad displays the error message whereas Java throws an exception (it depends on the Java app, I guess).
> 
> The behaviour aligns to the one seen when the printer is unreachable because of, let's say, network issues.

OK.

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PR: https://git.openjdk.java.net/jdk/pull/2915


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