Re: [platform-dev] Databinding Labelprovider + Chaining

[Christoph Läubrich <laeubi@xxxxxxxxxxxxxx>]

Thanks Jens, indeed I use the 'typed' variants but haven't found an 
example to link here :-)

Anyways you showed it worked and it seem I must have messed something up 
in my code so the type infos got screwed... I'll check that!

Am 21.04.21 um 15:38 schrieb Jens Lideström:
> Hello Christoph,
>
> Working with string-based properties got slightly more fiddly after the
> addition of type parameters to the databinding classes. But it also got a
> bit more clear and got more static type checking!
>
> The Vogella tutorial is apparently not updated to use new versions of the
> databinding framework.
>
> The best way to solve your problem is to use the versions of
> BeanProperties#value that also specify the return type.
>
> Like this:
>
> import org.eclipse.core.databinding.beans.typed.BeanProperties;
>
> ObservableListContentProvider<Person> contentProvider =
>      new ObservableListContentProvider<>();
>
> IObservableSet<Person> knownElements = contentProvider.getKnownElements();
>
> IObservableMap<Person, String> streetName =
> BeanProperties.value(Person.class, "address", Address.class)
>      .value(BeanProperties.value(Address.class, "street", String.class))
>      .observeDetail(knownElements);
>
> The above code type-checks fine.
>
> The other alternative is to specify Object as the type argument of
> ObservableListContentProvider. In that case you throw type information
> away and you have to work with Object all the way:
>
> ObservableListContentProvider<Object> contentProvider = new
>      ObservableListContentProvider<>();
>
> IObservableSet<Object> knownElements = contentProvider.getKnownElements();
>
> IObservableMap<Object, Object> streetName = BeanProperties.value("address")
>      .value(BeanProperties.value("street"))
>      .observeDetail(knownElements);
>
> BR,
> Jens Lideström
>
> On 2021-04-21 10:04, Christoph Läubrich wrote:
> > [1] shows how to observe a property of an object to have a label updating,
> > that works as long as it is a direct property of the (person) object.
> >
> > [2] shows how to chain properties to access "sub-objects" (lets say
> > persons address)
> >
> > But how do I combine both?
> >
> > IObservableMap streetName = BeanProperties.value(Person.class,
> >      "adress").value(BeanProperties.value(Address.class,
> >      "street")).observeDetail(knownElements);
> >
> > obviously won't work as the "knownElements" are of type
> > IObservableSet<Person> ...
> >
> >
> > [1]
> > https://www.vogella.com/tutorials/EclipseDataBinding/article.html#observing-list-details
> >
> > [2]
> > https://www.vogella.com/tutorials/EclipseDataBinding/article.html#chaining-properties
> >
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