[SQL][MINOR] rename present to finish in Aggregator

Author: Wenchen Fan <[email protected]>

Closes #9617 from cloud-fan/tmp.

Author: cloud-fan

sql/core/src/main/scala/org/apache/spark/sql/execution/aggregate/TypedAggregateExpression.scala

@@ -136,7 +136,7 @@ case class TypedAggregateExpression(
 
   override def eval(buffer: InternalRow): Any = {
     val b = boundB.shift(mutableAggBufferOffset).fromRow(buffer)
-    val result = cEncoder.toRow(aggregator.present(b))
+    val result = cEncoder.toRow(aggregator.finish(b))
     dataType match {
       case _: StructType => result
       case _ => result.get(0, dataType)

sql/core/src/main/scala/org/apache/spark/sql/expressions/Aggregator.scala

@@ -65,7 +65,7 @@ abstract class Aggregator[-A, B, C] {
   /**
    * Transform the output of the reduction.
    */
-  def present(reduction: B): C
+  def finish(reduction: B): C
 
   /**
    * Returns this `Aggregator` as a [[TypedColumn]] that can be used in [[Dataset]] or [[DataFrame]]

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

@@ -36,7 +36,7 @@ class SumOf[I, N : Numeric](f: I => N) extends Aggregator[I, N, N] with Serializ
 
   override def merge(b1: N, b2: N): N = numeric.plus(b1, b2)
 
-  override def present(reduction: N): N = reduction
+  override def finish(reduction: N): N = reduction
 }
 
 object TypedAverage extends Aggregator[(String, Int), (Long, Long), Double] with Serializable {
@@ -50,7 +50,7 @@ object TypedAverage extends Aggregator[(String, Int), (Long, Long), Double] with
     (b1._1 + b2._1, b1._2 + b2._2)
   }
 
-  override def present(countAndSum: (Long, Long)): Double = countAndSum._2 / countAndSum._1
+  override def finish(countAndSum: (Long, Long)): Double = countAndSum._2 / countAndSum._1
 }
 
 object ComplexResultAgg extends Aggregator[(String, Int), (Long, Long), (Long, Long)]
@@ -66,7 +66,7 @@ object ComplexResultAgg extends Aggregator[(String, Int), (Long, Long), (Long, L
     (b1._1 + b2._1, b1._2 + b2._2)
   }
 
-  override def present(reduction: (Long, Long)): (Long, Long) = reduction
+  override def finish(reduction: (Long, Long)): (Long, Long) = reduction
 }
 
 class DatasetAggregatorSuite extends QueryTest with SharedSQLContext {