Remove DataFrame.pivot monster method

Author: aray

sql/core/src/main/scala/org/apache/spark/sql/DataFrame.scala

@@ -988,41 +988,6 @@ class DataFrame private[sql](
     GroupedData(this, colNames.map(colName => resolve(colName)), GroupedData.CubeType)
   }
 
-  /**
-   * (Scala-specific) Pivots a column of the current [[DataFrame]] and preform the specified
-   * aggregation.
-   * {{{
-   *   // Compute the sum of earnings for each year by course with each course as a separate column.
-   *   df.pivot(Seq($"year"), $"course", Seq("dotNET", "Java"), sum($"earnings"))
-   * }}}
-   * @param groupBy Columns to group by.
-   * @param pivotColumn Column to pivot
-   * @param pivotValues Values of pivotColumn that will be translated to columns in the output data
-   *                    frame.
-   * @param aggregate Aggregate expression to preform for each combination of groupBy and
-   *                  pivotValues.
-   * @group dfops
-   * @since 1.6.0
-   */
-  def pivot(
-      groupBy: Seq[Column],
-      pivotColumn: Column,
-      pivotValues: Seq[String],
-      aggregate: Column): DataFrame = {
-
-    val aliasedGroupBy = groupBy.map(_.expr).map {
-      // Wrap UnresolvedAttribute with UnresolvedAlias, as when we resolve UnresolvedAttribute, we
-      // will remove intermediate Alias for ExtractValue chain, and we need to alias it again to
-      // make it a NamedExpression.
-      case u: UnresolvedAttribute => UnresolvedAlias(u)
-      case expr: NamedExpression => expr
-      case expr: Expression => Alias(expr, expr.prettyString)()
-    }
-
-    new DataFrame(sqlContext,
-      Pivot(aliasedGroupBy, pivotColumn.expr, pivotValues, Seq(aggregate.expr), this.logicalPlan))
-  }
-
   /**
    * (Scala-specific) Aggregates on the entire [[DataFrame]] without groups.
    * {{{

sql/core/src/test/scala/org/apache/spark/sql/DataFramePivotSuite.scala

@@ -23,20 +23,6 @@ import org.apache.spark.sql.test.SharedSQLContext
 class DataFramePivotSuite extends QueryTest with SharedSQLContext{
   import testImplicits._
 
-  test("pivot courses") {
-    checkAnswer(
-      courseSales.pivot(Seq($"year"), $"course", Seq("dotNET", "Java"), sum($"earnings")),
-      Row(2012, 15000.0, 20000.0) :: Row(2013, 48000.0, 30000.0) :: Nil
-    )
-  }
-
-  test("pivot year") {
-    checkAnswer(
-      courseSales.pivot(Seq($"course"), $"year", Seq("2012", "2013"), sum($"earnings")),
-      Row("dotNET", 15000.0, 48000.0) :: Row("Java", 20000.0, 30000.0) :: Nil
-    )
-  }
-
   test("pivot courses groupBy") {
     checkAnswer(
       courseSales.groupBy($"year").pivot($"course", "dotNET", "Java").agg(sum($"earnings")),