org.apache.spark.sql.Dataset<T> df
org.apache.spark.sql.Dataset<T> ds
org.apache.spark.sql.SparkSession ss
org.apache.spark.sql.SQLContext sc
org.apache.spark.streaming.dstream.DStream<T> ds
org.apache.spark.streaming.dstream.DStream<T> ds
org.apache.spark.streaming.dstream.DStream<T> ds