Hi, There are two ways:
1. make the non-serializable member variable transient (meaning that it won't be serialized) and check in the aggregate call if it has been initialized or not. 2. implement your own serialization logic by overriding readObject() and writeObject() [1]. Best, Fabian [1] https://howtodoinjava.com/java/serialization/custom-serialization-readobject-writeobject/ Am Do., 6. Juni 2019 um 23:04 Uhr schrieb Vijay Balakrishnan < bvija...@gmail.com>: > HI, > I have a class defined : > > public class MGroupingWindowAggregate implements AggregateFunction.. { >> private final Map<String, Object> keyHistMap = new TreeMap<>(); >> } >> > In the constructor, I initialize it. > >> public MGroupingWindowAggregate() { >> Histogram minHist = new Histogram(new >> SlidingTimeWindowReservoir(timeIntervalL, TimeUnit.MINUTES)); >> org.apache.flink.metrics.Histogram minHistogram = new >> DropwizardHistogramWrapper(minHist); >> Map<String, org.apache.flink.metrics.Histogram> intervalHistMap = new >> TreeMap<>(); >> intervalHistMap.putIfAbsent(interval, minHistogram); >> keyHistMap.putIfAbsent(operationKey, intervalHistMap); >> } >> > When trying to use it in the add() method of AggregateFunction, it fails > saying: > NotSerializableException: > org.apache.flink.dropwizard.metrics.DropwizardHistogramWrapper > > Tried to wrap DropwizardHistogramWrapper inside a serializable Object with > Composition but that also didn't work. > > Looked at using RichFunction open() based on Stephan's advise here. > https://stackoverflow.com/questions/34118469/flink-using-dagger-injections-not-serializable > But cannot use RichFunction with AggrgeateFunction or use > RichAggregateFunction > > How can I use the DropwizardHistogramWrapper -a non serializable class > inside my AggregateFunction ? Trying to use DropwizardHistogramWrapper to > get some Histogram percentile stats without re-inventing the wheel. > > TIA, > Vijay >
