Add test and formatting fixes

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/source/MergingMediaPeriod.java

@@ -25,9 +25,6 @@ import androidx.media3.common.util.Assertions;
 import androidx.media3.common.util.NullableType;
 import androidx.media3.exoplayer.LoadingInfo;
 import androidx.media3.exoplayer.SeekParameters;
-import androidx.media3.exoplayer.source.chunk.Chunk;
-import androidx.media3.exoplayer.source.chunk.MediaChunk;
-import androidx.media3.exoplayer.source.chunk.MediaChunkIterator;
 import androidx.media3.exoplayer.trackselection.ExoTrackSelection;
 import androidx.media3.exoplayer.trackselection.ForwardingTrackSelection;
 import com.google.common.collect.Lists;
@@ -36,7 +33,6 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.IdentityHashMap;
-import java.util.List;
 
 /** Merges multiple {@link MediaPeriod}s. */
 /* package */ final class MergingMediaPeriod implements MediaPeriod, MediaPeriod.Callback {
@@ -141,7 +137,8 @@ import java.util.List;
           TrackGroup mergedTrackGroup = mergedTrackSelection.getTrackGroup();
           TrackGroup childTrackGroup =
               checkNotNull(childTrackGroupByMergedTrackGroup.get(mergedTrackGroup));
-          childSelections[j] = new MergingMediaPeriodTrackSelection(mergedTrackSelection, childTrackGroup);
+          childSelections[j] =
+              new MergingMediaPeriodTrackSelection(mergedTrackSelection, childTrackGroup);
         } else {
           childSelections[j] = null;
         }
@@ -317,157 +314,44 @@ import java.util.List;
   private static final class MergingMediaPeriodTrackSelection extends ForwardingTrackSelection {
     private final TrackGroup trackGroup;
 
-    public MergingMediaPeriodTrackSelection(ExoTrackSelection trackSelection, TrackGroup trackGroup) {
+    public MergingMediaPeriodTrackSelection(
+        ExoTrackSelection trackSelection, TrackGroup trackGroup) {
       super(trackSelection);
       this.trackGroup = trackGroup;
     }
 
-    @Override
-    public @Type int getType() {
-      return getWrappedInstance().getType();
-    }
-
     @Override
     public TrackGroup getTrackGroup() {
       return trackGroup;
     }
 
-    @Override
-    public int length() {
-      return getWrappedInstance().length();
-    }
-
     @Override
     public Format getFormat(int index) {
       return trackGroup.getFormat(getWrappedInstance().getIndexInTrackGroup(index));
     }
 
-    @Override
-    public int getIndexInTrackGroup(int index) {
-      return getWrappedInstance().getIndexInTrackGroup(index);
-    }
-
     @Override
     public int indexOf(Format format) {
       return getWrappedInstance().indexOf(trackGroup.indexOf(format));
     }
 
-    @Override
-    public int indexOf(int indexInTrackGroup) {
-      return getWrappedInstance().indexOf(indexInTrackGroup);
-    }
-
-    @Override
-    public void enable() {
-      getWrappedInstance().enable();
-    }
-
-    @Override
-    public void disable() {
-      getWrappedInstance().disable();
-    }
-
     @Override
     public Format getSelectedFormat() {
       return trackGroup.getFormat(getWrappedInstance().getSelectedIndexInTrackGroup());
     }
 
     @Override
-    public int getSelectedIndexInTrackGroup() {
-      return getWrappedInstance().getSelectedIndexInTrackGroup();
-    }
-
-    @Override
-    public int getSelectedIndex() {
-      return getWrappedInstance().getSelectedIndex();
-    }
-
-    @Override
-    public @C.SelectionReason int getSelectionReason() {
-      return getWrappedInstance().getSelectionReason();
-    }
-
-    @Nullable
-    @Override
-    public Object getSelectionData() {
-      return getWrappedInstance().getSelectionData();
-    }
-
-    @Override
-    public void onPlaybackSpeed(float playbackSpeed) {
-      getWrappedInstance().onPlaybackSpeed(playbackSpeed);
-    }
-
-    @Override
-    public void onDiscontinuity() {
-      getWrappedInstance().onDiscontinuity();
-    }
-
-    @Override
-    public void onRebuffer() {
-      getWrappedInstance().onRebuffer();
-    }
-
-    @Override
-    public void onPlayWhenReadyChanged(boolean playWhenReady) {
-      getWrappedInstance().onPlayWhenReadyChanged(playWhenReady);
-    }
-
-    @Override
-    public void updateSelectedTrack(
-        long playbackPositionUs,
-        long bufferedDurationUs,
-        long availableDurationUs,
-        List<? extends MediaChunk> queue,
-        MediaChunkIterator[] mediaChunkIterators) {
-      getWrappedInstance().updateSelectedTrack(
-          playbackPositionUs, bufferedDurationUs, availableDurationUs, queue, mediaChunkIterators);
-    }
-
-    @Override
-    public int evaluateQueueSize(long playbackPositionUs, List<? extends MediaChunk> queue) {
-      return getWrappedInstance().evaluateQueueSize(playbackPositionUs, queue);
-    }
-
-    @Override
-    public boolean shouldCancelChunkLoad(
-        long playbackPositionUs, Chunk loadingChunk, List<? extends MediaChunk> queue) {
-      return getWrappedInstance().shouldCancelChunkLoad(playbackPositionUs, loadingChunk, queue);
-    }
-
-    @Override
-    public boolean excludeTrack(int index, long exclusionDurationMs) {
-      return getWrappedInstance().excludeTrack(index, exclusionDurationMs);
-    }
-
-    @Override
-    public boolean isTrackExcluded(int index, long nowMs) {
-      return getWrappedInstance().isTrackExcluded(index, nowMs);
-    }
-
-    @Override
-    public long getLatestBitrateEstimate() {
-      return getWrappedInstance().getLatestBitrateEstimate();
-    }
-
-    @Override
-    public boolean equals(@Nullable Object o) {
-      if (this == o) {
-        return true;
-      }
-      if (!(o instanceof MergingMediaPeriodTrackSelection)) {
+    public boolean equals(@Nullable Object other) {
+      if (!super.equals(other) || !(other instanceof MergingMediaPeriodTrackSelection)) {
         return false;
       }
-      MergingMediaPeriodTrackSelection that = (MergingMediaPeriodTrackSelection) o;
-      return getWrappedInstance().equals(that.getWrappedInstance()) && trackGroup.equals(that.trackGroup);
+      MergingMediaPeriodTrackSelection that = (MergingMediaPeriodTrackSelection) other;
+      return trackGroup.equals(that.trackGroup);
     }
 
     @Override
     public int hashCode() {
-      int result = 17;
-      result = 31 * result + trackGroup.hashCode();
-      result = 31 * result + getWrappedInstance().hashCode();
-      return result;
+      return 31 * super.hashCode() + trackGroup.hashCode();
     }
   }
 }

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/trackselection/ForwardingTrackSelection.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2016 The Android Open Source Project
+ * Copyright 2025 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -25,14 +25,25 @@ import androidx.media3.exoplayer.source.chunk.MediaChunk;
 import androidx.media3.exoplayer.source.chunk.MediaChunkIterator;
 import java.util.List;
 
+/** An {@link ExoTrackSelection} forwarding all calls to a wrapped instance. */
 @UnstableApi
 public class ForwardingTrackSelection implements ExoTrackSelection {
   private final ExoTrackSelection trackSelection;
 
+  /**
+   * Creates the forwarding track selection.
+   *
+   * @param trackSelection The wrapped {@link ExoTrackSelection}.
+   */
   public ForwardingTrackSelection(ExoTrackSelection trackSelection) {
     this.trackSelection = trackSelection;
   }
 
+  /** Returns the wrapped {@link ExoTrackSelection}. */
+  public ExoTrackSelection getWrappedInstance() {
+    return trackSelection;
+  }
+
   @Override
   public void enable() {
     trackSelection.enable();
@@ -90,11 +101,14 @@ public class ForwardingTrackSelection implements ExoTrackSelection {
   }
 
   @Override
-  public void updateSelectedTrack(long playbackPositionUs, long bufferedDurationUs,
-      long availableDurationUs, List<? extends MediaChunk> queue,
+  public void updateSelectedTrack(
+      long playbackPositionUs,
+      long bufferedDurationUs,
+      long availableDurationUs,
+      List<? extends MediaChunk> queue,
       MediaChunkIterator[] mediaChunkIterators) {
-    trackSelection.updateSelectedTrack(playbackPositionUs, bufferedDurationUs,
-        availableDurationUs, queue, mediaChunkIterators);
+    trackSelection.updateSelectedTrack(
+        playbackPositionUs, bufferedDurationUs, availableDurationUs, queue, mediaChunkIterators);
   }
 
   @Override
@@ -103,8 +117,8 @@ public class ForwardingTrackSelection implements ExoTrackSelection {
   }
 
   @Override
-  public boolean shouldCancelChunkLoad(long playbackPositionUs, Chunk loadingChunk,
-      List<? extends MediaChunk> queue) {
+  public boolean shouldCancelChunkLoad(
+      long playbackPositionUs, Chunk loadingChunk, List<? extends MediaChunk> queue) {
     return trackSelection.shouldCancelChunkLoad(playbackPositionUs, loadingChunk, queue);
   }
 
@@ -158,12 +172,9 @@ public class ForwardingTrackSelection implements ExoTrackSelection {
     return trackSelection.indexOf(indexInTrackGroup);
   }
 
-  public ExoTrackSelection getWrappedInstance() {
-    return trackSelection;
-  }
-
+  @Override
   public int hashCode() {
-    return getWrappedInstance().hashCode();
+    return trackSelection.hashCode();
   }
 
   @Override
@@ -171,11 +182,10 @@ public class ForwardingTrackSelection implements ExoTrackSelection {
     if (this == obj) {
       return true;
     }
-    if (obj == null || getClass() != obj.getClass()) {
+    if (!(obj instanceof ForwardingTrackSelection)) {
       return false;
     }
     ForwardingTrackSelection other = (ForwardingTrackSelection) obj;
-
-    return getWrappedInstance().equals(other.getWrappedInstance());
+    return trackSelection.equals(other.trackSelection);
   }
 }

libraries/exoplayer/src/test/java/androidx/media3/exoplayer/trackselection/ForwardingTrackSelectionTest.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2025 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package androidx.media3.exoplayer.trackselection;
+
+import static androidx.media3.test.utils.TestUtil.assertForwardingClassForwardsAllMethods;
+import static androidx.media3.test.utils.TestUtil.assertSubclassOverridesAllMethods;
+
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+/** Unit test for {@link ForwardingTrackSelection}. */
+@RunWith(AndroidJUnit4.class)
+public class ForwardingTrackSelectionTest {
+
+  @Test
+  public void overridesAllMethods() throws NoSuchMethodException {
+    assertSubclassOverridesAllMethods(ExoTrackSelection.class, ForwardingTrackSelection.class);
+  }
+
+  @Test
+  public void forwardsAllMethods() throws Exception {
+    assertForwardingClassForwardsAllMethods(ExoTrackSelection.class, ForwardingTrackSelection::new);
+  }
+}