Move local/remote playlist merge() to PlaylistLocalItem class

In order not to have a utils class just for one function

app/src/main/java/org/schabi/newpipe/database/playlist/PlaylistLocalItem.java

@@ -1,7 +1,33 @@
 package org.schabi.newpipe.database.playlist;
 
 import org.schabi.newpipe.database.LocalItem;
+import org.schabi.newpipe.database.playlist.model.PlaylistRemoteEntity;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
 
 public interface PlaylistLocalItem extends LocalItem {
     String getOrderingName();
+
+    static List<PlaylistLocalItem> merge(
+            final List<PlaylistMetadataEntry> localPlaylists,
+            final List<PlaylistRemoteEntity> remotePlaylists) {
+        final List<PlaylistLocalItem> items = new ArrayList<>(
+                localPlaylists.size() + remotePlaylists.size());
+        items.addAll(localPlaylists);
+        items.addAll(remotePlaylists);
+
+        Collections.sort(items, (left, right) -> {
+            final String on1 = left.getOrderingName();
+            final String on2 = right.getOrderingName();
+            if (on1 == null) {
+                return on2 == null ? 0 : 1;
+            } else {
+                return on2 == null ? -1 : on1.compareToIgnoreCase(on2);
+            }
+        });
+
+        return items;
+    }
 }

app/src/main/java/org/schabi/newpipe/local/bookmark/BookmarkFragment.java

@@ -29,7 +29,6 @@ import org.schabi.newpipe.local.playlist.RemotePlaylistManager;
 import org.schabi.newpipe.report.UserAction;
 import org.schabi.newpipe.util.NavigationHelper;
 import org.schabi.newpipe.util.OnClickGesture;
-import org.schabi.newpipe.util.PlaylistItemsUtils;
 
 import java.util.List;
 
@@ -138,7 +137,7 @@ public final class BookmarkFragment extends BaseLocalListFragment<List<PlaylistL
         super.startLoading(forceLoad);
 
         Flowable.combineLatest(localPlaylistManager.getPlaylists(),
-                remotePlaylistManager.getPlaylists(), PlaylistItemsUtils::merge)
+                remotePlaylistManager.getPlaylists(), PlaylistLocalItem::merge)
                 .onBackpressureLatest()
                 .observeOn(AndroidSchedulers.mainThread())
                 .subscribe(getPlaylistsSubscriber());

app/src/main/java/org/schabi/newpipe/settings/SelectPlaylistFragment.java

@@ -29,7 +29,6 @@ import org.schabi.newpipe.local.playlist.LocalPlaylistManager;
 import org.schabi.newpipe.local.playlist.RemotePlaylistManager;
 import org.schabi.newpipe.report.ErrorActivity;
 import org.schabi.newpipe.report.UserAction;
-import org.schabi.newpipe.util.PlaylistItemsUtils;
 
 import java.util.List;
 import java.util.Vector;
@@ -84,12 +83,12 @@ public class SelectPlaylistFragment extends DialogFragment {
         recyclerView.setVisibility(View.GONE);
         emptyView.setVisibility(View.GONE);
 
-        final AppDatabase database = NewPipeDatabase.getInstance(this.getContext());
+        final AppDatabase database = NewPipeDatabase.getInstance(requireContext());
         final LocalPlaylistManager localPlaylistManager = new LocalPlaylistManager(database);
         final RemotePlaylistManager remotePlaylistManager = new RemotePlaylistManager(database);
 
         playlistsSubscriber = Flowable.combineLatest(localPlaylistManager.getPlaylists(),
-                remotePlaylistManager.getPlaylists(), PlaylistItemsUtils::merge)
+                remotePlaylistManager.getPlaylists(), PlaylistLocalItem::merge)
                 .subscribe(this::displayPlaylists, this::onError);
 
         return v;

app/src/main/java/org/schabi/newpipe/util/PlaylistItemsUtils.java

@@ -1,38 +0,0 @@
-package org.schabi.newpipe.util;
-
-import org.schabi.newpipe.database.playlist.PlaylistLocalItem;
-import org.schabi.newpipe.database.playlist.PlaylistMetadataEntry;
-import org.schabi.newpipe.database.playlist.model.PlaylistRemoteEntity;
-
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.List;
-
-public final class PlaylistItemsUtils {
-    private PlaylistItemsUtils() { }
-
-    public static List<PlaylistLocalItem> merge(
-            final List<PlaylistMetadataEntry> localPlaylists,
-            final List<PlaylistRemoteEntity> remotePlaylists) {
-        final List<PlaylistLocalItem> items = new ArrayList<>(
-                localPlaylists.size() + remotePlaylists.size());
-        items.addAll(localPlaylists);
-        items.addAll(remotePlaylists);
-
-        Collections.sort(items, (left, right) -> {
-            String on1 = left.getOrderingName();
-            String on2 = right.getOrderingName();
-            if (on1 == null && on2 == null) {
-                return 0;
-            } else if (on1 != null && on2 == null) {
-                return -1;
-            } else if (on1 == null && on2 != null) {
-                return 1;
-            } else {
-                return on1.compareToIgnoreCase(on2);
-            }
-        });
-
-        return items;
-    }
-}