- Type Parameters:
T- the type of value being observed
- All Superinterfaces:
- Functional Interface:
- This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
Listener for pre-change events for observable values.
handleValueChangingThis method is called when the value is about to change and provides an opportunity to veto the change. The given event object must only be used locally in this method because it may be reused for other change notifications. The diff object referenced by the event is immutable and may be used non-locally.
event- the event