IValueChangingListener (Eclipse Platform API Specification)

Type Parameters:

T - the type of value being observed

All Superinterfaces:

IObservablesListener

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
```
@FunctionalInterface
public interface IValueChangingListener<T>
extends IObservablesListener
```
Listener for pre-change events for observable values.

Since:

1.0

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`handleValueChanging(ValueChangingEvent<T> event)`	This method is called when the value is about to change and provides an opportunity to veto the change.

- Method Detail
  - handleValueChanging
```
void handleValueChanging(ValueChangingEvent<T> event)
```
    This 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.
    
    Parameters:
    
    event - the event