[SPARK-5602][SQL] Better support for creating DataFrame from local data collection

1. Added methods to create DataFrames from Seq[Product]
2. Added executeTake to avoid running a Spark job on LocalRelations.

Author: Reynold Xin <rxin@databricks.com>

Closes #4372 from rxin/localDataFrame and squashes the following commits:

f696858 [Reynold Xin] style checker.
839ef7f [Reynold Xin] [SPARK-5602][SQL] Better support for creating DataFrame from local data collection.

3 files changed, 30 insertions, 11 deletions

diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/ScalaReflection.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/ScalaReflection.scala
index 8e79e532ca..0445f3aa07 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/ScalaReflection.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/ScalaReflection.scala
@@ -211,7 +211,7 @@ trait ScalaReflection {
      */
     def asRelation: LocalRelation = {
       val output = attributesFor[A]
-      LocalRelation(output, data)
+      LocalRelation.fromProduct(output, data)
     }
   }
 }
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/TestRelation.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/LocalRelation.scala
index d90af45b37..92bd057c6f 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/TestRelation.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/LocalRelation.scala
@@ -17,31 +17,34 @@
 
 package org.apache.spark.sql.catalyst.plans.logical
 
+import org.apache.spark.sql.Row
 import org.apache.spark.sql.catalyst.analysis
 import org.apache.spark.sql.catalyst.expressions.Attribute
-import org.apache.spark.sql.types.{StructType, StructField}
+import org.apache.spark.sql.types.{DataTypeConversions, StructType, StructField}
 
 object LocalRelation {
   def apply(output: Attribute*): LocalRelation = new LocalRelation(output)
 
-  def apply(output1: StructField, output: StructField*): LocalRelation = new LocalRelation(
-    StructType(output1 +: output).toAttributes
-  )
+  def apply(output1: StructField, output: StructField*): LocalRelation = {
+    new LocalRelation(StructType(output1 +: output).toAttributes)
+  }
+
+  def fromProduct(output: Seq[Attribute], data: Seq[Product]): LocalRelation = {
+    val schema = StructType.fromAttributes(output)
+    LocalRelation(output, data.map(row => DataTypeConversions.productToRow(row, schema)))
+  }
 }
 
-case class LocalRelation(output: Seq[Attribute], data: Seq[Product] = Nil)
+case class LocalRelation(output: Seq[Attribute], data: Seq[Row] = Nil)
   extends LeafNode with analysis.MultiInstanceRelation {
 
-  // TODO: Validate schema compliance.
-  def loadData(newData: Seq[Product]) = new LocalRelation(output, data ++ newData)
-
   /**
    * Returns an identical copy of this relation with new exprIds for all attributes.  Different
    * attributes are required when a relation is going to be included multiple times in the same
    * query.
    */
-  override final def newInstance: this.type = {
-    LocalRelation(output.map(_.newInstance), data).asInstanceOf[this.type]
+  override final def newInstance(): this.type = {
+    LocalRelation(output.map(_.newInstance()), data).asInstanceOf[this.type]
   }
 
   override protected def stringArgs = Iterator(output)
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/types/DataTypeConversions.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/types/DataTypeConversions.scala
index 21f478c80c..c243be07a9 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/types/DataTypeConversions.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/types/DataTypeConversions.scala
@@ -19,11 +19,27 @@ package org.apache.spark.sql.types
 
 import java.text.SimpleDateFormat
 
+import org.apache.spark.sql.Row
 import org.apache.spark.sql.catalyst.ScalaReflection
+import org.apache.spark.sql.catalyst.expressions.GenericMutableRow
 
 
 protected[sql] object DataTypeConversions {
 
+  def productToRow(product: Product, schema: StructType): Row = {
+    val mutableRow = new GenericMutableRow(product.productArity)
+    val schemaFields = schema.fields.toArray
+
+    var i = 0
+    while (i < mutableRow.length) {
+      mutableRow(i) =
+        ScalaReflection.convertToCatalyst(product.productElement(i), schemaFields(i).dataType)
+      i += 1
+    }
+
+    mutableRow
+  }
+
   def stringToTime(s: String): java.util.Date = {
     if (!s.contains('T')) {
       // JDBC escape string