if (notifyOnSet != null) {
synchronized (this) {
for (int i = 0; i < notifyOnSet.size() ; i++) {
PropertySetCallback psc = (PropertySetCallback) notifyOnSet.elementAt(i);
if (!psc.validate(key, value, d))
continue;
// if this property should not be used then
// don't call apply. This depends on where
// the old value comes from