[SPARK-13895][SQL] DataFrameReader.text should return Dataset[String]

## What changes were proposed in this pull request?
This patch changes DataFrameReader.text()'s return type from DataFrame to Dataset[String].

Closes #11731.

## How was this patch tested?
Updated existing integration tests to reflect the change.

Author: Reynold Xin <rxin@databricks.com>

Closes #11739 from rxin/SPARK-13895.

1 files changed, 4 insertions, 4 deletions

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 42554720ed..7fe17e0cf7 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
@@ -316,14 +316,14 @@ public class JavaDataFrameSuite {
 
   @Test
   public void testTextLoad() {
-    Dataset<Row> df1 = context.read().text(
+    Dataset<String> ds1 = context.read().text(
       Thread.currentThread().getContextClassLoader().getResource("text-suite.txt").toString());
-    Assert.assertEquals(4L, df1.count());
+    Assert.assertEquals(4L, ds1.count());
 
-    Dataset<Row> df2 = context.read().text(
+    Dataset<String> ds2 = context.read().text(
       Thread.currentThread().getContextClassLoader().getResource("text-suite.txt").toString(),
       Thread.currentThread().getContextClassLoader().getResource("text-suite2.txt").toString());
-    Assert.assertEquals(5L, df2.count());
+    Assert.assertEquals(5L, ds2.count());
   }
 
   @Test