XCOMMONS-1509: CancelableEvents are not propagated when they are canceled

[surli]

Issue

https://jira.xwiki.org/browse/XCOMMONS-1509

Solution

Override matches(Event) in AbstractCancelableEvent.

Tests

Add a new unit test to check the new behaviour.

[tmortagne]

This does not fully fix the issue IMO. A cancellable event is an event which implement CancelableEvent, they don't have to extend AbstractCancelableEvent which is just a helper. For example this won't work with ActionExecutingEvent.

In my mind it was DefaultObservationManager job to check if an event is cancelled before continuing to call listeners.

[surli]

In my mind in was DefaultObservationManager job to check if an event is cancelled before continuing to call listeners.

I understood, but I thought this implementation would allow more flexibility for this specific behaviour. i.e. if an user would want to trigger the listener no matter the state, then he can.

If we put it in the DefaultObservationManager, then we consider that this behaviour is fixed and cannot be changed.

Here it's really a choice to do IMO.