Dear community, I'd add to my topology a stateful operator - graced with a Store - demanded to save some compuation A.
I'd like to implement it so that it can store, by the same key, a list of values by appending A by events come in. Something similar e.g. in Apache Flink, this can be achieved by the ListState construct. When the semantic of the events change somehow, I'll trigger the emission of what I stored in my list state. I went through the window store code because I thought the base concept was quite simliar (appending events as they come and computing updates with the related iterator) but I wasn't able to find any inspiration. By now I'm considering a key value store, with a surrogate key like key = (event_key, nth-id-before-emission), which allows me to retrieve the list of computations when the trigger is fired. Are there better approaches by which achieving this task, either are there construct already making this possible? Thank you everybody. -- *Andrea Spina* Software Engineer @ Radicalbit Srl Via Borsieri 41, 20159, Milano - IT
