eclipse plugin - Trigger evaluation of PropertyTester

Question

The code from two years back had to be upgraded to E4, and now a bunch of stuff does not work anymore. One of these is the IEvaluationService if used like this:

<handler class="org.acme.PrintHandler" commandId="org.eclipse.ui.file.print">
  <activeWhen>
    <with variable="activePart">
      <test property="org.acme.printable" />
    </with>
  </activeWhen>
</handler>

IEvaluationService service = (IEvaluationService) PlatformUI.getWorkbench().getService(IEvaluationService.class);
service.requestEvaluation("org.acme.printable");

How do I (re)trigger the evaluation of a PropertyTester? Since E4 is really not even close to being production ready, I need a workaround for E3 (compatibility layer).

Related question - but this user was searching for the equivalent in E4, while I need one that works in E3.

Funnily enough, if I replace the <activeWhen> tags with <enabledWhen> it works. In that case IEventBroker#post and IEventBroker#send work, too.

This is a similar question. That user used Eclipse 4.2 - I tested the problem with 4.5, 4.6 and 4.7.

Answer 1

I'm going to share my workaround, which is not good, and does not work in alles cases. And only really works because in my use case I have a IWorkbenchPart with an ISelectionProvider... but maybe it will help the next person:

IWorkbenchPart activePart = // get active view or editor
ISelectionProvider selectionProvider = activePart.getSite().getSelectionProvider();
ISelection selection = selectionProvider.getSelection();
selectionProvider.setSelection(new StructuredSelection());
selectionProvider.setSelection(selection);

This code just resets the selection, which normally triggers the PropertyTester. I don't think it'll work if nothing was selected.