revert renaming

Author: lw-lin

sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/Source.scala

@@ -34,9 +34,9 @@ trait Source  {
   def getOffset: Option[Offset]
 
   /**
-   * Returns the data that is between the offsets (`start`, `end`]. When `start` is `None` then the
-   * returned data should begin with the first available record. This method must always return the
+   * Returns the data that is between the offsets (`start`, `end`]. When `start` is `None` then
+   * the batch should begin with the first available record. This method must always return the
    * same data for a particular `start` and `end` pair.
    */
-  def getData(start: Option[Offset], end: Offset): DataFrame
+  def getBatch(start: Option[Offset], end: Offset): DataFrame
 }