public void setAlert(final boolean ALERT) {
        if (null == alert) {
            _alert = ALERT;
            fireTileEvent(ALERT_EVENT);
        } else {
            if (!alert.isBound()) {
                alert.set(ALERT);
            }
        }
    }
Defines if the alert property should be set. This
property can be used to visualize an alert situation
in the skin.
@param ALERT
src/main/java/eu/hansolo/tilesfx/Tile.java