Clean up subclassing behaviour of AnalyticsCollector.

AnalyticsCollector is allowed to be subclassed to simplify adding
new events that make use of the EventTime generation.

Clean up the subclassing interface to simplify this:
 - Make generateCurrentPlayerMediaPeriodEventTime protected. This is
   arguably the most useful method for extended clients. Other
   generateXXXEventTime methods are left private as they can't be
   useful for extensions because they require some integration into
   the ExoPlayer playback thread to make sense. So keeping them
   private to cause less confusion.
 - Some existing callback handling should be final as all the others.
 - Adding @CallSuper to all lifecycle management methods that might
   be helpful to subclasses but require to call the super method.
 - Make sendEvent protected to let subclasses use the simple
   event sending method.

PiperOrigin-RevId: 351766369

library/core/src/main/java/com/google/android/exoplayer2/analytics/AnalyticsCollector.java

@@ -20,6 +20,7 @@ import static com.google.android.exoplayer2.util.Assertions.checkNotNull;
 import android.os.Looper;
 import android.util.SparseArray;
 import android.view.Surface;
+import androidx.annotation.CallSuper;
 import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.ExoPlaybackException;
@@ -110,6 +111,7 @@ public class AnalyticsCollector
    *
    * @param listener The listener to add.
    */
+  @CallSuper
   public void addListener(AnalyticsListener listener) {
     Assertions.checkNotNull(listener);
     listeners.add(listener);
@@ -120,6 +122,7 @@ public class AnalyticsCollector
    *
    * @param listener The listener to remove.
    */
+  @CallSuper
   public void removeListener(AnalyticsListener listener) {
     listeners.remove(listener);
   }
@@ -131,6 +134,7 @@ public class AnalyticsCollector
    * @param player The {@link Player} for which data will be collected.
    * @param looper The {@link Looper} used for listener callbacks.
    */
+  @CallSuper
   public void setPlayer(Player player, Looper looper) {
     Assertions.checkState(
         this.player == null || mediaPeriodQueueTracker.mediaPeriodQueue.isEmpty());
@@ -148,6 +152,7 @@ public class AnalyticsCollector
    * Releases the collector. Must be called after the player for which data is collected has been
    * released.
    */
+  @CallSuper
   public void release() {
     EventTime eventTime = generateCurrentPlayerMediaPeriodEventTime();
     eventTimes.put(AnalyticsListener.EVENT_PLAYER_RELEASED, eventTime);
@@ -166,7 +171,7 @@ public class AnalyticsCollector
    * @param readingPeriod The media period in the queue that is currently being read by renderers,
    *     or null if the queue is empty.
    */
-  public void updateMediaPeriodQueueInfo(
+  public final void updateMediaPeriodQueueInfo(
       List<MediaPeriodId> queue, @Nullable MediaPeriodId readingPeriod) {
     mediaPeriodQueueTracker.onQueueUpdated(queue, readingPeriod, checkNotNull(player));
   }
@@ -289,7 +294,7 @@ public class AnalyticsCollector
   }
 
   @Override
-  public void onAudioSinkError(Exception audioSinkError) {
+  public final void onAudioSinkError(Exception audioSinkError) {
     EventTime eventTime = generateReadingMediaPeriodEventTime();
     sendEvent(
         eventTime,
@@ -309,7 +314,7 @@ public class AnalyticsCollector
   }
 
   @Override
-  public void onAudioAttributesChanged(AudioAttributes audioAttributes) {
+  public final void onAudioAttributesChanged(AudioAttributes audioAttributes) {
     EventTime eventTime = generateReadingMediaPeriodEventTime();
     sendEvent(
         eventTime,
@@ -318,7 +323,7 @@ public class AnalyticsCollector
   }
 
   @Override
-  public void onSkipSilenceEnabledChanged(boolean skipSilenceEnabled) {
+  public final void onSkipSilenceEnabledChanged(boolean skipSilenceEnabled) {
     EventTime eventTime = generateReadingMediaPeriodEventTime();
     sendEvent(
         eventTime,
@@ -327,7 +332,7 @@ public class AnalyticsCollector
   }
 
   @Override
-  public void onVolumeChanged(float audioVolume) {
+  public final void onVolumeChanged(float audioVolume) {
     EventTime eventTime = generateReadingMediaPeriodEventTime();
     sendEvent(
         eventTime,
@@ -618,7 +623,7 @@ public class AnalyticsCollector
   }
 
   @Override
-  public void onPlaybackSuppressionReasonChanged(
+  public final void onPlaybackSuppressionReasonChanged(
       @PlaybackSuppressionReason int playbackSuppressionReason) {
     EventTime eventTime = generateCurrentPlayerMediaPeriodEventTime();
     sendEvent(
@@ -765,19 +770,28 @@ public class AnalyticsCollector
         listener -> listener.onDrmSessionReleased(eventTime));
   }
 
-  // Internal methods.
-
-  private void sendEvent(
-      EventTime eventTime,
-      @AnalyticsListener.EventFlags int eventFlag,
-      ListenerSet.Event<AnalyticsListener> eventInvocation) {
+  /**
+   * Sends an event to registered listeners.
+   *
+   * @param eventTime The {@link EventTime} to report.
+   * @param eventFlag An integer flag indicating the type of the event, or {@link C#INDEX_UNSET} to
+   *     report this event without flag.
+   * @param eventInvocation The event.
+   */
+  protected final void sendEvent(
+      EventTime eventTime, int eventFlag, ListenerSet.Event<AnalyticsListener> eventInvocation) {
     eventTimes.put(eventFlag, eventTime);
     listeners.sendEvent(eventFlag, eventInvocation);
   }
 
+  /** Generates an {@link EventTime} for the currently playing item in the player. */
+  protected final EventTime generateCurrentPlayerMediaPeriodEventTime() {
+    return generateEventTime(mediaPeriodQueueTracker.getCurrentPlayerMediaPeriod());
+  }
+
   /** Returns a new {@link EventTime} for the specified timeline, window and media period id. */
   @RequiresNonNull("player")
-  protected EventTime generateEventTime(
+  protected final EventTime generateEventTime(
       Timeline timeline, int windowIndex, @Nullable MediaPeriodId mediaPeriodId) {
     if (timeline.isEmpty()) {
       // Ensure media period id is only reported together with a valid timeline.
@@ -818,6 +832,8 @@ public class AnalyticsCollector
         player.getTotalBufferedDuration());
   }
 
+  // Internal methods.
+
   private EventTime generateEventTime(@Nullable MediaPeriodId mediaPeriodId) {
     checkNotNull(player);
     @Nullable
@@ -836,10 +852,6 @@ public class AnalyticsCollector
     return generateEventTime(knownTimeline, windowIndex, mediaPeriodId);
   }
 
-  private EventTime generateCurrentPlayerMediaPeriodEventTime() {
-    return generateEventTime(mediaPeriodQueueTracker.getCurrentPlayerMediaPeriod());
-  }
-
   private EventTime generatePlayingMediaPeriodEventTime() {
     return generateEventTime(mediaPeriodQueueTracker.getPlayingMediaPeriod());
   }