RFR: 8288137: The set of available printers is not updated without application restart

[Kevin Rushforth]

On Thu, 7 Jul 2022 22:23:55 GMT, Phil Race <prr at openjdk.org> wrote:

> This fixes the issue that the default printer or set of available printers is fixed from the first call to it in the lifetime of the application.
> Now subsequent calls will check to see if there are changes.
> A manual test is provided for verifying this - it requires you to add/remove printers at the system level to verify anything related to this fix.

I tested it on Windows by adding and removing a printer, and it does what I would expect. I left a couple questions on the implementation, along with a minor formatting issue. You'll also need to fix the whitespace error that `jcheck` reported.

modules/javafx.graphics/src/main/java/com/sun/prism/j2d/PrismPrintPipeline.java line 100:

> 98:     // The map is useful when updating
> 99:     private static HashMap<PrintService, Printer> pMap = new HashMap<>();
> 100:     //private static TreeSet<Printer> printers = null;

Since this is unused, I recommend to remove it.

modules/javafx.graphics/src/main/java/com/sun/prism/j2d/PrismPrintPipeline.java line 138:

> 136:             }
> 137:         }
> 138:         lastTime = System.currentTimeMillis();

Is `lastTime` intended to be the last time you updated the printers or the last time the `getAllPrinters` method was called? If the former, then you would want to set `lastTime` right after `updatePrinters`. If the latter, then it's fine where it is.

modules/javafx.graphics/src/main/java/com/sun/prism/j2d/PrismPrintPipeline.java line 192:

> 190:         if (oldDefaultService != null && newDefaultService != null) {
> 191:             if (!oldDefaultService.equals(newDefaultService)) {
> 192:                 defaultPrinter = findDefaultPrinter(printerSet, newDefaultService);

Don't you also want to find the default printer in the case where the old `default` printer was null and the `newDefaultService` is not null?

modules/javafx.graphics/src/main/java/javafx/print/Printer.java line 95:

> 93:         } else {
> 94:         defaultPrinter.setValue(p);
> 95:     }

Minor: indentation is off for these two lines

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PR: https://git.openjdk.org/jfx/pull/817