[news.eclipse.platform] Re: [DataBinding] JavaBeansObservable not updati

[Matthew Hall <matthall@xxxxxxxxxxxxxxxxx>]

Arrays.asList returns a list that is *backed* by the passed in array. 
Since arrays cannot change length, neither can the list.  To make the 
list fully modifiable, try using an ArrayList with the copy constructor:

list = new ArrayList(Arrays.asList(array));

Matthew

Masroor Ahmad wrote:
> Hello,
> during development with the databinding framework I found a strange 
> behaviour of the JavaBeansObservable (M20070822-0800):
>
> Suppose we run the following simple code:
>
> ModelBean modelBean = new ModelBean();
> ModelBean targetBean = new ModelBean();
>
> IObservableList modelBeanObservableList = 
> BeansObservables.observeList(Realm.getDefault(), modelBean, "list", 
> String.class);
> IObservableList targetBeanObservableList = 
> BeansObservables.observeList(Realm.getDefault(), targetBean, "list", 
> String.class);
>
> DataBindingContext bindingContext = new DataBindingContext();
> bindingContext.bindList(targetBeanObservableList, modelBeanObservableList, 
> null, null);
>
> modelBean.add("Str 1");
> modelBean.clear();
> targetBean.add("Str 2");
> for(Object o : modelBean.getList()){
>  System.out.println(o);
> }
>
> ModelBean has a simple array list containing strings and clear() resets the 
> list. Any other modification of the list can be imagined.
> One would expect the console to output: "Str2". But surprisingly there is no 
> output at all - the model was not updated.
> When I debugged the code of JavaBeansObservable I found out the place, where 
> the underlying writeableList is updated:
>
> public void add(int index, Object element) {
> ...
>  wrappedList.add(index, element);
> ...
> }
>
> But this line throws an exception (UnsupportedOperationException?) as 
> wrappedList is not of type ArrayList but Arrays$ArrayList.
>
> I question myself, what did I wrong?
>
> Nice Greetings,
> Masroor