[SPARK-6409][SQL] It is not necessary that avoid old inteface of hive, because this will make some UDAF can not work.

spark avoid old inteface of hive, then some udaf can not work like "org.apache.hadoop.hive.ql.udf.generic.GenericUDAFAverage"

Author: DoingDone9 <799203320@qq.com>

Closes apache#5131 from DoingDone9/udaf and squashes the following commits:

9de08d0 [DoingDone9] Update HiveUdfSuite.scala
49c62dc [DoingDone9] Update hiveUdfs.scala
98b134f [DoingDone9] Merge pull request #5 from apache/master
161cae3 [DoingDone9] Merge pull request #4 from apache/master
c87e8b6 [DoingDone9] Merge pull request #3 from apache/master
cb1852d [DoingDone9] Merge pull request #2 from apache/master
c3f046f [DoingDone9] Merge pull request #1 from apache/master

Author: pzzs

sql/hive/src/main/scala/org/apache/spark/sql/hive/hiveUdfs.scala

@@ -375,9 +375,8 @@ private[hive] case class HiveUdafFunction(
 
   private val returnInspector = function.init(GenericUDAFEvaluator.Mode.COMPLETE, inspectors)
 
-  // Cast required to avoid type inference selecting a deprecated Hive API.
   private val buffer =
-    function.getNewAggregationBuffer.asInstanceOf[GenericUDAFEvaluator.AbstractAggregationBuffer]
+    function.getNewAggregationBuffer
 
   override def eval(input: Row): Any = unwrap(function.evaluate(buffer), returnInspector)
 

sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/HiveUdfSuite.scala

@@ -22,7 +22,7 @@ import java.util
 import java.util.Properties
 
 import org.apache.hadoop.conf.Configuration
-import org.apache.hadoop.hive.ql.udf.generic.GenericUDF
+import org.apache.hadoop.hive.ql.udf.generic.{GenericUDAFAverage, GenericUDF}
 import org.apache.hadoop.hive.ql.udf.generic.GenericUDF.DeferredObject
 import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory
 import org.apache.hadoop.hive.serde2.objectinspector.{ObjectInspector, ObjectInspectorFactory}
@@ -93,6 +93,15 @@ class HiveUdfSuite extends QueryTest {
     sql("DROP TEMPORARY FUNCTION IF EXISTS testUdf")
   }
 
+  test("SPARK-6409 UDAFAverage test") {
+    sql(s"CREATE TEMPORARY FUNCTION test_avg AS '${classOf[GenericUDAFAverage].getName}'")
+    checkAnswer(
+      sql("SELECT test_avg(1), test_avg(substr(value,5)) FROM src"),
+      Seq(Row(1.0, 260.182)))
+    sql("DROP TEMPORARY FUNCTION IF EXISTS test_avg")
+    TestHive.reset()
+  }
+  
   test("SPARK-2693 udaf aggregates test") {
     checkAnswer(sql("SELECT percentile(key, 1) FROM src LIMIT 1"),
       sql("SELECT max(key) FROM src").collect().toSeq)