Method dispatch

src/main/java/fieldbox/boxes/Keyboard.java:47–104

(Box root, Window.Event<Window.KeyboardState> event)

		Set<Integer> released = Window.KeyboardState.keysReleased(event.before, event.after);
		Set<Integer> down = event.after.keysDown;

		released.stream().map(r -> ongoingDrags.remove(r)).filter(x -> x != null).forEach(drags -> {
			drags.stream().forEach(Hold -> Hold.update(event, true));
			drags.clear();
		});

		for (Collection<Hold> d : ongoingDrags.values()) {
			Iterator<Hold> dd = d.iterator();
			while (dd.hasNext()) {
				Hold Hold = dd.next();
				boolean cont = false;
				try {
					cont = Hold.update(event, false);
				} catch (Throwable t) {
					System.err.println(" Exception thrown in Hold update :" + t);
					System.err.println(" Hold will not be called again");
					cont = false;
				}
				if (!cont) dd.remove();
			}
		}

		Box focused = root.find(KeyboardFocus._keyboardFocus, root.both()).map(x -> x.getFocus()).findFirst().orElseGet(() -> Optional.empty()).orElseGet(() -> root);

		Util.Errors errors = new Util.Errors();
		pressed.stream().forEach(p -> {
			Collection<Hold> hold = ongoingDrags.computeIfAbsent(p, (x) -> new ArrayList<>());

			// change map to handle errors on x

			focused.find(onKeyDown, root.both())
			    .flatMap(x -> x.values()
					   .stream())
			    .map(Util.wrap(x -> x.onKeyDown(event, p), errors, null, Hold.class))
			    .filter(x -> x != null)
			    .collect(Collectors.toCollection(() -> hold));
		});

		typed.stream().forEach(p -> {
			focused.find(onCharTyped, root.both()).flatMap(x -> x.values().stream()).forEach(x -> x.onCharTyped(event, p));
		});
		if (errors.hasErrors()) {
			errors.getErrors()
			      .forEach(x -> {
				      x.first.printStackTrace();
			      });
		}

	}
}