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Re: [e4-dev] Designflaw in our ExtendedObjectSupplier system
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Yep, known bug:
Bug 398728 [DI] ExtendedObjectSupplier annotations ignored if requested item is satisfied by the PrimaryObjectSupplier
https://bugs.eclipse.org/bugs/show_bug.cgi?id=398728
The injector needs to see if there's a known annotation for an extended supplier. But this seemed too big a change for 4.3.
Brian.
On 10-Jul-2013, at 11:12 AM, Tom Schindl <tom.schindl@xxxxxxxxxxxxxxx> wrote:
> Hi,
>
> While giving a e4 workshop we discovered what I think is a big flaw in
> our ExtendedObjectSupplier system making it unusable for @UIEventTopic
> and @Preferences.
>
> Suppose the following implementation:
>
> public class MyPart {
>
> public void init(IEclipseContext context) {
> ListViewer v = ....
> v.addSelectionChangedListener( new .... {
> ....
> context.set(Person.class, p);
> }
> }
>
> @Inject
> @Optional
> public void personCreated(@UIEventTopic("person/new")Person p) {
> // ...
> }
> }
>
>
> public class NewPersonHandler {
> @Execute
> public void execute(IEventBroker b) {
> Person p = ...
> b.send("person/new",p);
> }
> }
>
> Things you'll observe:
> a) modifying the selection will call personCreated
> b) personCreated will only receive the object created in
> NewPersonHandler the selection has not changed afterwards the method
> is called but the value passed is the one written to the context
>
> The only solution to this problem is to make the event handler look like
> this:
>
> @Inject
> @Optional
> public void personCreated(@UIEventTopic("person/new")
> @Named(akeythatsneverused) Person p) {
> // ...
> }
>
>
> The reason for this wrong behavior is that the core DI system has no
> ideas about the extended supplier and so it is the main source for the
> look up, in case this look up succeeds because someone pushed something
> exactly below this key in the context (or in the parent hierarchy) the
> event receiving is broken.
>
> I'm not yet sure what needs to be done to fix this but without this our
> nice @Preference and @*EventTopic solution is unusable.
>
>
> Tom
> _______________________________________________
> e4-dev mailing list
> e4-dev@xxxxxxxxxxx
> https://dev.eclipse.org/mailman/listinfo/e4-dev
