---------- Forwarded message ----------
From: Yogesh Vyas <informy...@gmail.com>
Date: Thu, Oct 15, 2015 at 6:08 PM
Subject: Get the previous state string
To: user@spark.apache.org
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?
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