Addressed PR comments.

streaming/src/main/scala/org/apache/spark/streaming/dstream/FileInputDStream.scala

@@ -33,7 +33,7 @@ import org.apache.spark.util.{TimeStampedHashMap, Utils}
  * This class represents an input stream that monitors a Hadoop-compatible filesystem for new
  * files and creates a stream out of them. The way it works as follows.
  *
- * At each batch interval, the file system is queries for files in the given directory and
+ * At each batch interval, the file system is queried for files in the given directory and
  * detected new files are selected for that batch. In this case "new" means files that
  * became visible to readers during that time period. Some extra care is needed to deal
  * with the fact that files may become visible after they are created. For this purpose, this
@@ -50,7 +50,7 @@ import org.apache.spark.util.{TimeStampedHashMap, Utils}
  *
  * The trailing end of the window is the "ignore threshold" and all files whose mod times
  * are less than this threshold are assumed to have already been selected and are therefore
- * ignored. Files whose mode times are within the "remember window" are checked against files
+ * ignored. Files whose mod times are within the "remember window" are checked against files
  * that have already been selected. At a high level, this is how new files are identified in
  * each batch - files whose mod times are greater than the ignore threshold and
  * have not been considered within the remember window. See the documentation on the method
@@ -61,8 +61,8 @@ import org.apache.spark.util.{TimeStampedHashMap, Utils}
  *   the streaming app.
  * - If a file is to be visible in the directory listings, it must be visible within a certain
  *   duration of the mod time of the file. This duration is the "remember window", which is set to
- *   1 minute (see `FileInputDStream.REMEMBER_DURATION`). Otherwise, the file will not be
- *   selected as the mod time will be less than the ignore threshold when it become visible.
+ *   1 minute (see `FileInputDStream.MIN_REMEMBER_DURATION`). Otherwise, the file will never be
+ *   selected as the mod time will be less than the ignore threshold when it becomes visible.
  * - Once a file is visible, the mod time cannot change. If it does due to appends, then the
  *   processing semantics are undefined.
  */
@@ -316,15 +316,15 @@ object FileInputDStream {
    * older than this "window" of remembering will be ignored. So if new files are visible
    * within this window, then the file will get selected in the next batch.
    */
-  private val REMEMBER_DURATION = Minutes(1)
+  private val MIN_REMEMBER_DURATION = Minutes(1)
 
   def defaultFilter(path: Path): Boolean = !path.getName().startsWith(".")
 
   /**
    * Calculate the number of last batches to remember, such that all the files selected in
-   * at least last REMEMBER_DURATION duration can be remembered.
+   * at least last MIN_REMEMBER_DURATION duration can be remembered.
    */
   def calculateNumBatchesToRemember(batchDuration: Duration): Int = {
-    math.ceil(REMEMBER_DURATION.milliseconds.toDouble / batchDuration.milliseconds).toInt
+    math.ceil(MIN_REMEMBER_DURATION.milliseconds.toDouble / batchDuration.milliseconds).toInt
   }
 }