Promote addEventHandler/removeEventHandler to EventTarget interface

[Michael Strauß]

I think defaulting to UnsupportedOperationException is a good choice.
This shouldn't break existing usages of 3rd party implementations,
since they wouldn't be calling those APIs anyway.


On Fri, Mar 18, 2022 at 10:55 PM John Hendrikx <john.hendrikx at gmail.com> wrote:
>
> [...]
> EventTarget is already public API, and so there might be 3rd party
> implementations.  This means that the methods added to the EventTarget
> interface must be default methods. It would be super if these default
> implementations would just work out of the box, but that would require
> exposing the internal class EventHandlerManager (and adding a
> `getEventHandlerManager` to the `EventTarget` interface).  If that's not
> realistic, then initially the default implementations would have to
> throw UnsupportedOperationException.
>
> --John
>