Hi, I think this is an important fact to know also for consumers (not only for JCR providers). Therefore I proposed the following clarification in Javadoc: https://github.com/apache/sling-org-apache-sling-api/pull/63. Just think about a case where for example a cache is invalidated through a listener. In that case you cannot rely on the fact that this happens immediately after the commit, but may happen some time afterwards.
For example a request which is reading from the cache after in a previous request the resource has been changed, does not necessarily have the outdated cache already invalidated. Konrad > On 28. Jun 2025, at 15:39, Jörg Hoh <jhoh...@googlemail.com.INVALID> wrote: > > Hi Konrad, > > With the term "synchronous or asynchronous" you are probably referring in > relation to the event, which they are called upon. Or in other words: are > they part of the underlying transaction which is causing a change or are > they independent of it. > > In the context of JCR ResourceChangeListeners are called asynchronously to > the change it (implementation-wise in the JCR ObservationEvent handler > threads). While technically we could leave it unspecified and let the > implementation decide if it's synchronous and asynchronous (and therefor it > might have even the chance to influence the transaction), I would favor a > spec which requires asynchronous execution, as we have it right now with > JCR. And for that I am +1 to adding such a description to the API doc. > > Jörg > > > > > > Am Fr., 27. Juni 2025 um 17:12 Uhr schrieb Konrad Windszus <k...@apache.org >> : > >> Hi, >> Currently the javadoc at >> https://www.javadoc.io/doc/org.apache.sling/org.apache.sling.api/latest/org/apache/sling/api/resource/observation/ResourceChangeListener.html >> does not specify when exactly the listener is called and if that happens >> synchronously or asynchronously. If it happens synchronously it should also >> be clarified if other ResourceResolvers already may see those changes or >> not yet. >> >> Looking at >> https://github.com/apache/sling-org-apache-sling-jcr-resource/blob/fe35d53a1b0f8ff1a7616909f16539b759bd0bdd/src/main/java/org/apache/sling/jcr/resource/internal/JcrResourceListener.java#L97 >> it seems it inherits from >> https://developer.adobe.com/experience-manager/reference-materials/spec/javax.jcr/javadocs/jcr-2.0/javax/jcr/observation/EventListener.html >> >> "Event listeners are notified asynchronously, and see events after they >> occur and the transaction is committed.” >> >> I think adding a similar sentence to the Javadoc of ResourceChangeListener >> would be helpful. WDYT? >> Are all event listeners of resource resolvers supposed to behave like this? >> >> Konrad > > > > -- > https://cqdump.joerghoh.de
