BubblingValidator proposal about jidefx-oss

[jidesoft]

Are you saying it will install the validator to all children nodes based on certain criteria? JideFX has FXUtils which has setRecursively method. You should be able to use it in combination with ValidationUtils to do what you need. If I misunderstood, please feel free to let me know.

[mcondarelli]

Actually it turns out it is not necessary to install multiple EventHandlers.
It is enough to install a single one in the topmost Node,
but it would be very useful to make ValidationEvent implement Comparable.
This would enable to keep track of "most important" error found in the whole group.
Provisionally I defined:

    static public int getWeight(EventType<?> et) {
        if (et.equals(VALIDATION_UNKNOWN)) 
            return -1;
        else if (et.equals(VALIDATION_OK))
            return 0;
        else if (et.equals(VALIDATION_INFO))
            return 1;
        else if (et.equals(VALIDATION_WARNING))
            return 2;
        else if (et.equals(VALIDATION_ERROR))
            return 3;
        else
            return 5;
    }
    static public int getWeight(ValidationEvent ve) {
        return getWeight(ve.getEventType());
    }
    public static int compare(Event a, Event b) {
        return Integer.compare(getWeight(a.getEventType()), getWeight(b.getEventType()));
    }
    public static int compare(Event a, EventType<? extends Event> b) {
        return Integer.compare(getWeight(a.getEventType()), getWeight(b));
    }
    public static int compare(EventType<? extends Event> a, Event b) {
        return Integer.compare(getWeight(a), getWeight(b.getEventType()));
    }

This could be refined using provided id to fine tune.
Unfortunately I did't find an easy way to subclass EventType to make it Comparable because the class is final. This is why I resorted to static methods.

Typical use in EventHandler would be:

        gp.addEventHandler(ValidationEvent.ANY, new EventHandler<ValidationEvent>() {
            Map<Object, ValidationEvent> events = new HashMap<>();
            @Override
            public void handle(ValidationEvent event) {
                ValidationEvent old = events.get(event.getTarget());
                if (old == null || !old.getEventType().equals(event.getEventType())) {
                    events.put(event.getTarget(), event);
                    ValidationEvent evt = ValidationEvent.UNKNOWN;
                    for (ValidationEvent e : events.values()) {
                        if (compare(e, evt) > 0)
                            evt = e;
                    }
                    ok.setDisable(compare(evt, ValidationEvent.VALIDATION_INFO) > 0);
                }
            }
        });

It would be useful to wrap the internal machinery keeping track of validation statuses into a static method in ValidationUtils.
Some caching could improve efficency, if the number of validated widgets is particularly high.