Hi, I am new to Spark and was trying to do some experiments with it. I had a JavaPairDStream<String, List<String>> RDD. I want to get the list of string from its previous state. For that I use updateStateByKey function as follows:
final Function2<List<String>, Optional<List<String>>, Optional<List<String>>> updateFunc = new Function2<List<String>, Optional<List<String>>, Optional<List<String>>>() { public Optional<List<String>> call(List<String> arg0, Optional<List<String>> arg1) throws Exception { // TODO Auto-generated method stub if(arg1.toString()==null) return Optional.of(arg0); else { arg0.add(arg1.toString()); return Optional.of(arg0); } } }; I want the function to append the new list of string to the previous list and return the new list. But I am not able to do so. I am getting the " java.lang.UnsupportedOperationException" error. Can anyone which help me out in getting the desired output? --------------------------------------------------------------------- To unsubscribe, e-mail: user-unsubscr...@spark.apache.org For additional commands, e-mail: user-h...@spark.apache.org