如何展平RDD <List> ？

Question

I am fairly new to Spark and using Java to do functional programming with Casandra as datasource. As an output of a map task I getting a list of strings.

JavaRDD<List<String>> crows = sessions.map(new Function<Session, List<String>>() {});

I want to convert variable crows from type JavaRDD<List<String>> to JavaRDD<String> ie want to flatten out. Can someone suggest a way to do this?

Answer 1

According to @UniLocal the following works:

JavaRDD<String> crows = sessions.flatMap(new FlatMapFunction<Session, String>() {
    public Iterable<String>  call(T x) {
        List<String> someList = ...
        return someList;
    }
});