I am working on a `CoProcessFunction` that uses a third party library for detecting certain patterns of events based on some rules. So, in the end, the `ProcessElement1` method is basically forwarding the events to this library and registering a callback so that, when a match is detected, the CoProcessFunction can emit an output event. For achieving this, the callback relies on a reference to the `out: Collector[T]` parameter in `ProcessElement1`.
Having said that, I am not sure whether this use case is well-supported by Flink, since: 1. There might be multiple threads spanned by the third party library (let's I have not any control over the amount of threads spanned, this is decided by the library) 2. I am not sure whether `out` might be recreated or something by Flink at some point, invalidating the references in the callbacks, making them crash So far I have not observed any issues, but I have just run my program in the small. It would be great to hear from the experts whether my approach is valid or not. PS: Also posted in https://stackoverflow.com/questions/60181678/using-multithreaded-library-within-processfunction-with-callbacks-relying-on-the -- Sent from: http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/
