mstahv
commented
6 months ago Drafted what the change could be in https://github.com/vaadin/flow/commit/3203659f29933187c281962d1d620d0aedf0f2fb
In case people use events in "creative ways" a more stable solution might be to do the same in the constructor and save it to a field in ComponentEvent. But This would then be a bit of an overhed (until JIT compilation optimisations kick in 🤷♂️).
UI reference is often needed for various tasks. Because of the previous Optional buzz Component.getUI returns an Optional and leads to obsolete "rituals" in UI code or usaged of somewhat less elegant UI.getCurrent() that draws the UI from a thread local.
Because UI is pretty much always present when ComponentEvent is fired, it could maybe provide a shorthand for it.
For example this snippet in an event listener (e being ComponentEvent):
... would become
And the UI exprience would become better if something really goes wrong: the user/developer would see an exception instead of simply non-functional UI (exception eated).
Describe alternatives you've considered
Keep writing the ugly code.
Additional context
About the potential implementation: there are some edge case where UI might still be null, e.g. setting a value for a textfield that is not yet attached. In these cases in 99.9% of the time the value coming from thread local would still be valid. I'd use that as a fallback and document the behaviour in JavaDoc.