Wait for JavaFX Application Thread to complete event processing?

Question

Many questions are asked here about how to suspend a JavaFX application thread for a background thread, but I want the opposite!

I am trying to check how long it takes to fully process a number of key inputs. I use the Automaton test library for JavaFX, and editor.type (key) generates a keystroke event that is handled by the application. Here is one of many attempts:

long start = System.nanoTime(); editor.type(AGUtils.LEFT_ARROW); editor.type(AGUtils.LEFT_ARROW); editor.type(AGUtils.RIGHT_ARROW); editor.type(AGUtils.RIGHT_ARROW); FutureTask<Callable> t = new FutureTask<>(...); Platform.runLater(t); while (!t.isDone()) { } // wait for the FutureTask to be called long end = System.nanoTime(); 

However, it seems that the FX application thread can handle FutureTask before it handles the rest of the keystroke events.

TL; DR: I want to accurately measure when the JavaFX Application Thread finished processing the four keypress events that I generate.

How can i do this? Thanks!

Answer 1

Use ExecutorService and wait for your threads to finish. Save the timestamp when you start the service, and then compare the difference between the two points to get an answer.

A simple example of using ExecutorService :

 ExecutorService taskExecutor = Executors.newFixedThreadPool(4); while(...) { taskExecutor.execute(new MyTask()); } taskExecutor.shutdown(); try { taskExecutor.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS); } catch (InterruptedException e) { ... }