[SPARK-7153] [SQL] support all integral type ordinal in GetArrayItem

first convert `ordinal` to `Number`, then convert to int type.

Author: Wenchen Fan <cloud0fan@outlook.com>

Closes #5706 from cloud-fan/7153 and squashes the following commits:

915db79 [Wenchen Fan] fix 7153

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/ExtractValue.scala

@@ -186,7 +186,7 @@ case class GetArrayItem(child: Expression, ordinal: Expression)
     // TODO: consider using Array[_] for ArrayType child to avoid
     // boxing of primitives
     val baseValue = value.asInstanceOf[Seq[_]]
-    val index = ordinal.asInstanceOf[Int]
+    val index = ordinal.asInstanceOf[Number].intValue()
     if (index >= baseValue.size || index < 0) {
       null
     } else {

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/complexTypes.scala → sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/complexTypeCreator.scala

@@ -17,7 +17,6 @@
 
 package org.apache.spark.sql.catalyst.expressions
 
-import org.apache.spark.sql.catalyst
 import org.apache.spark.sql.types._
 
 

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/ComplexTypeSuite.scala

@@ -26,6 +26,26 @@ import org.apache.spark.unsafe.types.UTF8String
 
 class ComplexTypeSuite extends SparkFunSuite with ExpressionEvalHelper {
 
+  /**
+   * Runs through the testFunc for all integral data types.
+   *
+   * @param testFunc a test function that accepts a conversion function to convert an integer
+   *                 into another data type.
+   */
+  private def testIntegralDataTypes(testFunc: (Int => Any) => Unit): Unit = {
+    testFunc(_.toByte)
+    testFunc(_.toShort)
+    testFunc(identity)
+    testFunc(_.toLong)
+  }
+
+  test("GetArrayItem") {
+    testIntegralDataTypes { convert =>
+      val array = Literal.create(Seq("a", "b"), ArrayType(StringType))
+      checkEvaluation(GetArrayItem(array, Literal(convert(1))), "b")
+    }
+  }
+
   test("CreateStruct") {
     val row = InternalRow(1, 2, 3)
     val c1 = 'a.int.at(0).as("a")