[how-to use implicit class] how-to use implicit classes #scala #implicits #implicit #Row #scope

how-to-use-implicit-class

package com.corp.dept.spark.dfutils

import org.apache.spark.sql.Row

object RowEnhancements {

  implicit class RowExtender(row: Row) {

    def isNullAtCol(cellName: String): Boolean = {
      val index: Int = row.fieldIndex(cellName)

      if (row.isNullAt(index)) {
        return true
      }

      false
    }
  }
}


// and use it like this 

package com.corp.dept.biz.pckg

import com.corp.dept.spark.dfutils.RowEnhancements._ // obs !!! otherwise no joy !!!

class FooBar {

  // just an example method using the implicit class , hence the logic
 
  def firstRowColumnIsNull(df:DataFrame,col:String) {

    val row: Row = df.first()
    return row.isNullAtCol(col)  // Action !!! <- here the method of the implicit class is used 
  }

}