private void fireEventByAction(final Map<EntityAction, List<Handler>> map, final EntityEvent event,
                                   final EntityAction action) {
        final List<Handler> list = map.get(action);
        if (list != null) {
            for (final Handler handler : list) {
                try {
                    handler.onChange(event);
                } catch (final RuntimeException e) {
                    LOGGER.error("Unable to handle onChange event!", e);
                }
            }
        }
    }
Check to see if we can find a handler for this event. If there isn't one
then there is no point in firing the event.
stroom-core/src/main/java/stroom/core/entity/event/EntityEventHandler.java