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

MLnick

class HyperLogLogStoreUDAF extends UserDefinedAggregateFunction {

  override def inputSchema = new StructType()
    .add("stringInput", BinaryType)

  override def update(buffer: MutableAggregationBuffer, input: Row) = {
    // This input Row only has a single column storing the input value in String (or other Binary data).
    // We only update the buffer when the input value is not null.
    if (!input.isNullAt(0)) {
      if (buffer.isNullAt(0)) {