HADOOP-18156. Address JavaDoc warnings in classes like MarkerTool, S3ObjectAttributes, etc (#4965)

Contributed by Ankit Saurabh

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/impl/DirMarkerTracker.java

@@ -34,20 +34,20 @@
  * Tracks directory markers which have been reported in object listings.
  * This is needed for auditing and cleanup, including during rename
  * operations.
- * <p></p>
+ * <p>
  * Designed to be used while scanning through the results of listObject
  * calls, where are we assume the results come in alphanumeric sort order
  * and parent entries before children.
- * <p></p>
+ * <p>
  * This lets as assume that we can identify all leaf markers as those
  * markers which were added to set of leaf markers and not subsequently
  * removed as a child entries were discovered.
- * <p></p>
+ * <p>
  * To avoid scanning datastructures excessively, the path of the parent
  * directory of the last file added is cached. This allows for a
  * quick bailout when many children of the same directory are
  * returned in a listing.
- * <p></p>
+ * <p>
  * Consult the directory_markers document for details on this feature,
  * including terminology.
  */
@@ -106,7 +106,7 @@ public class DirMarkerTracker {
 
   /**
    * Construct.
-   * <p></p>
+   * <p>
    * The base path is currently only used for information rather than
    * validating paths supplied in other methods.
    * @param basePath base path of track
@@ -128,7 +128,7 @@ public Path getBasePath() {
 
   /**
    * A marker has been found; this may or may not be a leaf.
-   * <p></p>
+   * <p>
    * Trigger a move of all markers above it into the surplus map.
    * @param path marker path
    * @param key object key
@@ -160,7 +160,7 @@ public List<Marker> fileFound(Path path,
 
   /**
    * A path has been found.
-   * <p></p>
+   * <p>
    * Declare all markers above it as surplus
    * @param path marker path
    * @param key object key
@@ -187,7 +187,7 @@ private List<Marker> pathFound(Path path,
   /**
    * Remove all markers from the path and its parents from the
    * {@link #leafMarkers} map.
-   * <p></p>
+   * <p>
    * if {@link #recordSurplusMarkers} is true, the marker is
    * moved to the surplus map. Not doing this is simply an
    * optimisation designed to reduce risk of excess memory consumption
@@ -223,7 +223,7 @@ public Map<Path, Marker> getLeafMarkers() {
 
   /**
    * Get the map of surplus markers.
-   * <p></p>
+   * <p>
    * Empty if they were not being recorded.
    * @return all surplus markers.
    */

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/impl/DirectoryPolicy.java

@@ -69,21 +69,21 @@ enum MarkerPolicy {
 
     /**
      * Delete markers.
-     * <p></p>
+     * <p>
      * This is the classic S3A policy,
      */
     Delete(DIRECTORY_MARKER_POLICY_DELETE),
 
     /**
      * Keep markers.
-     * <p></p>
+     * <p>
      * This is <i>Not backwards compatible</i>.
      */
     Keep(DIRECTORY_MARKER_POLICY_KEEP),
 
     /**
      * Keep markers in authoritative paths only.
-     * <p></p>
+     * <p>
      * This is <i>Not backwards compatible</i> within the
      * auth paths, but is outside these.
      */

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/impl/OperationCallbacks.java

@@ -119,6 +119,7 @@ RemoteIterator<S3ALocatedFileStatus> listFilesAndDirectoryMarkers(
    * There's no update of metadata, directory markers, etc.
    * Callers must implement.
    * @param srcKey source object path
+   * @param destKey destination object path
    * @param srcAttributes S3 attributes of the source object
    * @param readContext the read context
    * @return the result of the copy

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/impl/RenameOperation.java

@@ -53,16 +53,16 @@
 
 /**
  * A parallelized rename operation.
- * <p></p>
+ * <p>
  * The parallel execution is in groups of size
  * {@link InternalConstants#RENAME_PARALLEL_LIMIT}; it is only
  * after one group completes that the next group is initiated.
- * <p></p>
+ * <p>
  * Once enough files have been copied that they meet the
  * {@link InternalConstants#MAX_ENTRIES_TO_DELETE} threshold, a delete
  * is initiated.
  * If it succeeds, the rename continues with the next group of files.
- * <p></p>
+ * <p>
  * Directory Markers which have child entries are never copied; only those
  * which represent empty directories are copied in the rename.
  * The {@link DirMarkerTracker} tracks which markers must be copied, and
@@ -71,10 +71,10 @@
  * the copied tree. This is to ensure that even if a directory tree
  * is copied from an authoritative path to a non-authoritative one
  * there is never any contamination of the non-auth path with markers.
- * <p></p>
+ * <p>
  * The rename operation implements the classic HDFS rename policy of
  * rename(file, dir) renames the file under the directory.
- * <p></p>
+ * <p>
  *
  * There is <i>no</i> validation of input and output paths.
  * Callers are required to themselves verify that destination is not under
@@ -178,7 +178,7 @@ private void completeActiveCopies(String reason) throws IOException {
 
   /**
    * Queue an object for deletion.
-   * <p></p>
+   * <p>
    * This object will be deleted when the next page of objects to delete
    * is posted to S3. Therefore, the COPY must have finished
    * before that deletion operation takes place.
@@ -204,9 +204,9 @@ private void queueToDelete(Path path, String key) {
 
   /**
    * Queue a list of markers for deletion.
-   * <p></p>
+   * <p>
    * no-op if the list is empty.
-   * <p></p>
+   * <p>
    * See {@link #queueToDelete(Path, String)} for
    * details on safe use of this method.
    *
@@ -221,7 +221,7 @@ private void queueToDelete(
 
   /**
    * Queue a single marker for deletion.
-   * <p></p>
+   * <p>
    * See {@link #queueToDelete(Path, String)} for
    * details on safe use of this method.
    *
@@ -427,7 +427,7 @@ protected void recursiveDirectoryRename() throws IOException {
 
   /**
    * Operations to perform at the end of every loop iteration.
-   * <p></p>
+   * <p>
    * This may block the thread waiting for copies to complete
    * and/or delete a page of data.
    */
@@ -448,11 +448,11 @@ private void endOfLoopActions() throws IOException {
   /**
    * Process all directory markers at the end of the rename.
    * All leaf markers are queued to be copied in the store;
-   * <p></p>
+   * <p>
    * Why not simply create new markers? All the metadata
    * gets copied too, so if there was anything relevant then
    * it would be preserved.
-   * <p></p>
+   * <p>
    * At the same time: markers aren't valued much and may
    * be deleted without any safety checks -so if there was relevant
    * data it is at risk of destruction at any point.
@@ -461,7 +461,7 @@ private void endOfLoopActions() throws IOException {
    * Be advised though: the costs of the copy not withstanding,
    * it is a lot easier to have one single type of scheduled copy operation
    * than have copy and touch calls being scheduled.
-   * <p></p>
+   * <p>
    * The duration returned is the time to initiate all copy/delete operations,
    * including any blocking waits for active copies and paged deletes
    * to execute. There may still be outstanding operations

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/s3guard/S3GuardTool.java

@@ -82,7 +82,7 @@
 
 /**
  * CLI to manage S3Guard Metadata Store.
- * <p></p>
+ * <p>
  * Some management tools invoke this class directly.
  */
 @InterfaceAudience.LimitedPrivate("management tools")
@@ -526,7 +526,6 @@ public int run(String[] args, PrintStream out)
      * Validate the marker options.
      * @param out output stream
      * @param fs filesystem
-     * @param path test path
      * @param marker desired marker option -may be null.
      */
     private void processMarkerOption(final PrintStream out,

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/tools/MarkerTool.java

@@ -147,7 +147,7 @@ public final class MarkerTool extends S3GuardTool {
   /**
    * Constant to use when there is no limit on the number of
    * objects listed: {@value}.
-   * <p></p>
+   * <p>
    * The value is 0 and not -1 because it allows for the limit to be
    * set on the command line {@code -limit 0}.
    * The command line parser rejects {@code -limit -1} as the -1
@@ -475,17 +475,23 @@ public String toString() {
           '}';
     }
 
-    /** Exit code to report. */
+    /**
+     * @return Exit code to report.
+     */
     public int getExitCode() {
       return exitCode;
     }
 
-    /** Tracker which did the scan. */
+    /**
+     * @return Tracker which did the scan.
+     */
     public DirMarkerTracker getTracker() {
       return tracker;
     }
 
-    /** Summary of purge. Null if none took place. */
+    /**
+     * @return Summary of purge. Null if none took place.
+     */
     public MarkerPurgeSummary getPurgeSummary() {
       return purgeSummary;
     }
@@ -661,7 +667,7 @@ private String suffix(final int size) {
    * @param path path to scan
    * @param tracker tracker to update
    * @param limit limit of files to scan; -1 for 'unlimited'
-   * @return true if the scan completedly scanned the entire tree
+   * @return true if the scan completely scanned the entire tree
    * @throws IOException IO failure
    */
   @Retries.RetryTranslated
@@ -840,6 +846,7 @@ public void setVerbose(final boolean verbose) {
    * Execute the marker tool, with no checks on return codes.
    *
    * @param scanArgs set of args for the scanner.
+   * @throws IOException IO failure
    * @return the result
    */
   @SuppressWarnings("IOResourceOpenedButNotSafelyClosed")
@@ -853,9 +860,9 @@ public static MarkerTool.ScanResult execMarkerTool(
 
   /**
    * Arguments for the scan.
-   * <p></p>
+   * <p>
    * Uses a builder/argument object because too many arguments were
-   * being created and it was making maintenance harder.
+   * being created, and it was making maintenance harder.
    */
   public static final class ScanArgs {
 
@@ -960,43 +967,71 @@ public static final class ScanArgsBuilder {
     /** Consider only markers in nonauth paths as errors. */
     private boolean nonAuth = false;
 
-    /** Source FS; must be or wrap an S3A FS. */
+    /**
+     * Source FS; must be or wrap an S3A FS.
+     * @param source Source FileSystem
+     * @return the builder class after scanning source FS
+     */
     public ScanArgsBuilder withSourceFS(final FileSystem source) {
       this.sourceFS = source;
       return this;
     }
 
-    /** Path to scan. */
+    /**
+     * Path to scan.
+     * @param p path to scan
+     * @return builder class for method chaining
+     */
     public ScanArgsBuilder withPath(final Path p) {
       this.path = p;
       return this;
     }
 
-    /** Purge? */
+    /**
+     * Should the markers be purged? This is also enabled when using the clean flag on the CLI.
+     * @param d set to purge if true
+     * @return builder class for method chaining
+     */
     public ScanArgsBuilder withDoPurge(final boolean d) {
       this.doPurge = d;
       return this;
     }
 
-    /** Min marker count (ignored on purge). */
+    /**
+     * Min marker count an audit must find (ignored on purge).
+     * @param min Minimum Marker Count (default 0)
+     * @return builder class for method chaining
+     */
     public ScanArgsBuilder withMinMarkerCount(final int min) {
       this.minMarkerCount = min;
       return this;
     }
 
-    /** Max marker count (ignored on purge). */
+    /**
+     * Max marker count an audit must find (ignored on purge).
+     * @param max Maximum Marker Count (default 0)
+     * @return builder class for method chaining
+     */
     public ScanArgsBuilder withMaxMarkerCount(final int max) {
       this.maxMarkerCount = max;
       return this;
     }
 
-    /** Limit of files to scan; 0 for 'unlimited'. */
+    /**
+     * Limit of files to scan; 0 for 'unlimited'.
+     * @param l Limit of files to scan
+     * @return builder class for method chaining
+     */
     public ScanArgsBuilder withLimit(final int l) {
       this.limit = l;
       return this;
     }
 
-    /** Consider only markers in nonauth paths as errors. */
+    /**
+     * Consider only markers in non-authoritative paths as errors.
+     * @param b True if tool should only consider markers in non-authoritative paths
+     * @return builder class for method chaining
+     */
     public ScanArgsBuilder withNonAuth(final boolean b) {
       this.nonAuth = b;
       return this;