[weld-dev] AfterBeanDiscovery and observer resolver cache
Hi everyone,
CDI extensions can observe the AfterBeanDiscovery event to register observer methods
(addObserverMethod). However, when an event is first fired, the observers for that event
are resolved and then cached (in TypeSafeResolver). All future calls to addObserverMethod
for an already fired event with corresponding qualifiers will have no effect because the
observer result is read from cache and not recomputed.
From an API perspective that's unfortunate because
addObserverMethod will only work until an event (with corresponding qualifiers) is fired
and there is no indication to the caller of that method that it didn't have any effect
when invoked after that.
Possible solutions:
- Provide some public API to clear/recompute that part the observer cache. Maybe that
exists? I couldn't find it which is why I am using the private API and Reflection :(.
Also let AfterBeanDiscovery.addObserverMethod fail in that case with the advice to reset
the cache.
- Recompute the corresponding part of the cache when addObserverMethod is called (seems
preferable).
OpenWebBeans doesn't have this issue as their NotificationManager will simply add the
new ObserverMethod to a ConcurrentHashMap that is also accessed when an event is fired.
What do you think? Can this already be done or is there another solution?
Cheers,
Christian