[SPARK-10630] [SQL] Add a createDataFrame API that takes in a java list

It would be nice to support creating a DataFrame directly from a Java List of Row.

Author: Holden Karau <holden@pigscanfly.ca>

Closes #8779 from holdenk/SPARK-10630-create-DataFrame-from-Java-List.

2 files changed, 24 insertions, 0 deletions

diff --git a/sql/core/src/main/scala/org/apache/spark/sql/SQLContext.scala b/sql/core/src/main/scala/org/apache/spark/sql/SQLContext.scala
index f099940800..1bd4e26fb3 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/SQLContext.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/SQLContext.scala
@@ -477,6 +477,20 @@ class SQLContext(@transient val sparkContext: SparkContext)
   }
 
   /**
+   * :: DeveloperApi ::
+   * Creates a [[DataFrame]] from an [[java.util.List]] containing [[Row]]s using the given schema.
+   * It is important to make sure that the structure of every [[Row]] of the provided List matches
+   * the provided schema. Otherwise, there will be runtime exception.
+   *
+   * @group dataframes
+   * @since 1.6.0
+   */
+  @DeveloperApi
+  def createDataFrame(rows: java.util.List[Row], schema: StructType): DataFrame = {
+    DataFrame(self, LocalRelation.fromExternalRows(schema.toAttributes, rows.asScala))
+  }
+
+  /**
    * Applies a schema to an RDD of Java Beans.
    *
    * WARNING: Since there is no guaranteed ordering for fields in a Java Bean,
diff --git a/sql/core/src/test/java/test/org/apache/spark/sql/JavaDataFrameSuite.java b/sql/core/src/test/java/test/org/apache/spark/sql/JavaDataFrameSuite.java
index 5f9abd4999..250ac2e109 100644
--- a/sql/core/src/test/java/test/org/apache/spark/sql/JavaDataFrameSuite.java
+++ b/sql/core/src/test/java/test/org/apache/spark/sql/JavaDataFrameSuite.java
@@ -37,6 +37,7 @@ import org.apache.spark.sql.*;
 import static org.apache.spark.sql.functions.*;
 import org.apache.spark.sql.test.TestSQLContext;
 import org.apache.spark.sql.types.*;
+import static org.apache.spark.sql.types.DataTypes.*;
 
 public class JavaDataFrameSuite {
   private transient JavaSparkContext jsc;
@@ -181,6 +182,15 @@ public class JavaDataFrameSuite {
     }
   }
 
+  @Test
+  public void testCreateDataFromFromList() {
+    StructType schema = createStructType(Arrays.asList(createStructField("i", IntegerType, true)));
+    List<Row> rows = Arrays.asList(RowFactory.create(0));
+    DataFrame df = context.createDataFrame(rows, schema);
+    Row[] result = df.collect();
+    Assert.assertEquals(1, result.length);
+  }
+
   private static final Comparator<Row> crosstabRowComparator = new Comparator<Row>() {
     @Override
     public int compare(Row row1, Row row2) {