create bucket of sorted data by ascending timestamp by (user, activity)

gistfile1.java

// create bucket of sorted data by ascending timestamp by (user, activity)
JavaRDD<Long> times = cassandraRowsRDD.select("timestamp")
                                      .where("user_id=? AND activity=?", i, activity)
                                      .withAscOrder()
                                      .map(CassandraRow::toMap)
                                      .map(entry -> (long) entry.get("timestamp"))
                                      .cache();