[news.eclipse.platform] Re: [Databinding] Problem with AggregateValidati

[Matthew Hall <matthall@xxxxxxxxxxxxxxxxx>]

Try using an IValueChangeListener instead of IChangeListener:

aggregateValidationStatus.addValueChangeListener(
  new IValueChangeListener() {
    public void handleValueChange(ValueChangeEvent event) {
      event.getObservableValue().getValue();
    }
  } );

Matthew

Kai Schlamp wrote:
> So, Schroedinger's cat ... nice analogy ... I hope my 
> AggregateValidationStatus doesn't contain any transitional states ;-)
>
> And yes, it works now when calling getValue inside the change listener.
> Is there an easy way to get the AggregateValidationStatus from within 
> the change listener? A "(AggregateValidationStatus) event.getSource())" 
> results in a ClassCastException (java.lang.ClassCastException:
> org.eclipse.core.databinding.AggregateValidationStatus$1 cannot be
> cast to org.eclipse.core.databinding.AggregateValidationStatus).
> Do I really have to pass the AggregateValidationStatus to the change 
> listener myself?
>
> Thank you,
> Kai
>
> > Are you doing anything with the value of the 
> > AggregateValidationStatus? in the change listener?  AVS is backed by a 
> > ComputedValue which fires an event once and doesn't fire any more 
> > until you look at the new value. It's kind of like Schroedinger's 
> > cat--you don't get any more change events until you look in the safe.  
> > See ObservableTracker.getterCalled(IObservable).  Then see 
> > IObservableValue and look for methods tagged @TrackedGetter.
> >
> > We do this to avoid an event storm if several observables are changed 
> > rapidly.  I think it will fix your problem just to call getValue() on 
> > the AVS inside the change listener.