From 327a5730a883aa6725a629763a3df0cebda30d03 Mon Sep 17 00:00:00 2001
From: Xiang Rong Lin <41164160+XiangRongLin@users.noreply.github.com>
Date: Sun, 2 Feb 2020 18:15:47 +0100
Subject: [PATCH] [Youtube] Add some comments to mix

---
 .../extractor/services/youtube/YoutubeParsingHelper.java  | 6 ++++++
 .../youtube/extractors/YoutubeMixPlaylistExtractor.java   | 4 ++++
 .../linkHandler/YoutubePlaylistLinkHandlerFactory.java    | 8 ++++++++
 3 files changed, 18 insertions(+)

diff --git a/extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubeParsingHelper.java b/extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubeParsingHelper.java
index 42420a1a7..258799692 100644
--- a/extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubeParsingHelper.java
+++ b/extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubeParsingHelper.java
@@ -192,6 +192,12 @@ public class YoutubeParsingHelper {
         }
     }
 
+    /**
+     * Checks if the given playlist id is a mix (auto-generated playlist)
+     * Ids from a mix start with "RD"
+     * @param playlistId
+     * @return Whether given id belongs to a mix
+     */
     public static boolean isYoutubeMixId(String playlistId) {
         return playlistId.startsWith("RD");
     }
diff --git a/extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/extractors/YoutubeMixPlaylistExtractor.java b/extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/extractors/YoutubeMixPlaylistExtractor.java
index 64281931c..9da2e98fd 100644
--- a/extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/extractors/YoutubeMixPlaylistExtractor.java
+++ b/extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/extractors/YoutubeMixPlaylistExtractor.java
@@ -18,6 +18,10 @@ import org.schabi.newpipe.extractor.services.youtube.linkHandler.YoutubeParsingH
 import org.schabi.newpipe.extractor.stream.StreamInfoItem;
 import org.schabi.newpipe.extractor.stream.StreamInfoItemsCollector;
 
+/**
+ * A YoutubePlaylistExtractor for a mix (auto-generated playlist).
+ * It handles urls in the format of "youtube.com/watch?v=videoId&list=playlistId"
+ */
 public class YoutubeMixPlaylistExtractor extends PlaylistExtractor {
 
   private Document doc;
diff --git a/extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/linkHandler/YoutubePlaylistLinkHandlerFactory.java b/extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/linkHandler/YoutubePlaylistLinkHandlerFactory.java
index 3d0ba78a5..ae66660c3 100644
--- a/extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/linkHandler/YoutubePlaylistLinkHandlerFactory.java
+++ b/extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/linkHandler/YoutubePlaylistLinkHandlerFactory.java
@@ -71,6 +71,14 @@ public class YoutubePlaylistLinkHandlerFactory extends ListLinkHandlerFactory {
         return true;
     }
 
+    /**
+     * If it is a mix (auto-generated playlist) url, return a Linkhandler where the url is like
+     * youtube.com/watch?v=videoId&list=playlistId
+     * <p>Otherwise use super</p>
+     * @param url
+     * @return
+     * @throws ParsingException
+     */
     @Override
     public ListLinkHandler fromUrl(String url) throws ParsingException {
         try {