@Override
 protected void afterDoImpl(ValueChangeCommand<T_VALUE> cmd) {
   afterChange(cmd.getPmAttr(), cmd.getOldValue(), cmd.getNewValue());
 }
 @Override
 protected boolean beforeDoImpl(ValueChangeCommand<T_VALUE> cmd) {
   return beforeChange(cmd.getPmAttr(), cmd.getOldValue(), cmd.getNewValue());
 }