[SPARK-14988][PYTHON] SparkSession API follow-ups

## What changes were proposed in this pull request?

Addresses comments in #12765.

## How was this patch tested?

Python tests.

Author: Andrew Or <andrew@databricks.com>

Closes #12784 from andrewor14/python-followup.

6 files changed, 28 insertions, 4 deletions

diff --git a/sql/core/src/main/scala/org/apache/spark/sql/Dataset.scala b/sql/core/src/main/scala/org/apache/spark/sql/Dataset.scala
index 1439d14980..08be94e8d4 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/Dataset.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/Dataset.scala
@@ -2308,7 +2308,7 @@ class Dataset[T] private[sql](
    * @since 1.6.0
    */
   def registerTempTable(tableName: String): Unit = {
-    sparkSession.registerDataFrameAsTable(toDF(), tableName)
+    sparkSession.registerTable(toDF(), tableName)
   }
 
   /**
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/RuntimeConfig.scala b/sql/core/src/main/scala/org/apache/spark/sql/RuntimeConfig.scala
index bf97d728b8..f2e851520e 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/RuntimeConfig.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/RuntimeConfig.scala
@@ -72,6 +72,15 @@ class RuntimeConfig private[sql](sqlConf: SQLConf = new SQLConf) {
    *
    * @since 2.0.0
    */
+  def get(key: String, default: String): String = {
+    sqlConf.getConfString(key, default)
+  }
+
+  /**
+   * Returns the value of Spark runtime configuration property for the given key.
+   *
+   * @since 2.0.0
+   */
   def getOption(key: String): Option[String] = {
     try Option(get(key)) catch {
       case _: NoSuchElementException => None
@@ -86,4 +95,12 @@ class RuntimeConfig private[sql](sqlConf: SQLConf = new SQLConf) {
   def unset(key: String): Unit = {
     sqlConf.unsetConf(key)
   }
+
+  /**
+   * Returns whether a particular key is set.
+   */
+  protected[sql] def contains(key: String): Boolean = {
+    sqlConf.contains(key)
+  }
+
 }
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 1f08a61aea..6dfac3d7ae 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
@@ -600,7 +600,7 @@ class SQLContext private[sql](
    * only during the lifetime of this instance of SQLContext.
    */
   private[sql] def registerDataFrameAsTable(df: DataFrame, tableName: String): Unit = {
-    sparkSession.registerDataFrameAsTable(df, tableName)
+    sparkSession.registerTable(df, tableName)
   }
 
   /**
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/SparkSession.scala b/sql/core/src/main/scala/org/apache/spark/sql/SparkSession.scala
index 2814b70c9c..11c0aaab23 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/SparkSession.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/SparkSession.scala
@@ -577,7 +577,7 @@ class SparkSession private(
    * Registers the given [[DataFrame]] as a temporary table in the catalog.
    * Temporary tables exist only during the lifetime of this instance of [[SparkSession]].
    */
-  protected[sql] def registerDataFrameAsTable(df: DataFrame, tableName: String): Unit = {
+  protected[sql] def registerTable(df: DataFrame, tableName: String): Unit = {
     sessionState.catalog.createTempTable(
       sessionState.sqlParser.parseTableIdentifier(tableName).table,
       df.logicalPlan,
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/command/cache.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/command/cache.scala
index ec3fadab50..f05401b02b 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/command/cache.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/command/cache.scala
@@ -30,7 +30,7 @@ case class CacheTableCommand(
 
   override def run(sparkSession: SparkSession): Seq[Row] = {
     plan.foreach { logicalPlan =>
-      sparkSession.registerDataFrameAsTable(Dataset.ofRows(sparkSession, logicalPlan), tableName)
+      sparkSession.registerTable(Dataset.ofRows(sparkSession, logicalPlan), tableName)
     }
     sparkSession.catalog.cacheTable(tableName)
 
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/internal/SQLConf.scala b/sql/core/src/main/scala/org/apache/spark/sql/internal/SQLConf.scala
index 2bfc895678..7de7748211 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/internal/SQLConf.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/internal/SQLConf.scala
@@ -755,6 +755,13 @@ private[sql] class SQLConf extends Serializable with CatalystConf with Logging {
     }.toSeq
   }
 
+  /**
+   * Return whether a given key is set in this [[SQLConf]].
+   */
+  def contains(key: String): Boolean = {
+    settings.containsKey(key)
+  }
+
   private def setConfWithCheck(key: String, value: String): Unit = {
     if (key.startsWith("spark.") && !key.startsWith("spark.sql.")) {
       logWarning(s"Attempt to set non-Spark SQL config in SQLConf: key = $key, value = $value")