tzachz

import org.apache.spark.SparkContext
import org.apache.spark.sql.expressions.{MutableAggregationBuffer, UserDefinedAggregateFunction}
import org.apache.spark.sql.types._
import org.apache.spark.sql.{Column, Row, SQLContext}

/***
  * UDAF combining maps, overriding any duplicate key with "latest" value
  * @param keyType DataType of Map key
  * @param valueType DataType of Value key
  * @param merge function to merge values of identical keys