Replace MutableFlags by immutable class

PiperOrigin-RevId: 362043183

extensions/cast/src/main/java/com/google/android/exoplayer2/ext/cast/CastPlayer.java

@@ -95,7 +95,7 @@ public final class CastPlayer extends BasePlayer {
   private final SeekResultCallback seekResultCallback;
 
   // Listeners and notification.
-  private final ListenerSet<Player.EventListener, Player.Events> listeners;
+  private final ListenerSet<Player.EventListener> listeners;
   @Nullable private SessionAvailabilityListener sessionAvailabilityListener;
 
   // Internal state.
@@ -139,8 +139,7 @@ public final class CastPlayer extends BasePlayer {
         new ListenerSet<>(
             Looper.getMainLooper(),
             Clock.DEFAULT,
-            Player.Events::new,
-            (listener, eventFlags) -> listener.onEvents(/* player= */ this, eventFlags));
+            (listener, flags) -> listener.onEvents(/* player= */ this, new Events(flags)));
 
     playWhenReady = new StateHolder<>(false);
     repeatMode = new StateHolder<>(REPEAT_MODE_OFF);

extensions/ima/src/test/java/com/google/android/exoplayer2/ext/ima/FakePlayer.java

@@ -27,7 +27,7 @@ import com.google.android.exoplayer2.util.ListenerSet;
 /** A fake player for testing content/ad playback. */
 /* package */ final class FakePlayer extends StubExoPlayer {
 
-  private final ListenerSet<EventListener, Events> listeners;
+  private final ListenerSet<EventListener> listeners;
   private final Timeline.Period period;
 
   private Timeline timeline;
@@ -45,8 +45,7 @@ import com.google.android.exoplayer2.util.ListenerSet;
         new ListenerSet<>(
             Looper.getMainLooper(),
             Clock.DEFAULT,
-            Player.Events::new,
-            (listener, eventFlags) -> listener.onEvents(/* player= */ this, eventFlags));
+            (listener, flags) -> listener.onEvents(/* player= */ this, new Events(flags)));
     period = new Timeline.Period();
     state = Player.STATE_IDLE;
     playWhenReady = true;

library/common/src/main/java/com/google/android/exoplayer2/Player.java

@@ -15,11 +15,9 @@
  */
 package com.google.android.exoplayer2;
 
-import static com.google.android.exoplayer2.util.Assertions.checkState;
 
 import android.content.Context;
 import android.os.Looper;
-import android.util.SparseBooleanArray;
 import android.view.Surface;
 import android.view.SurfaceHolder;
 import android.view.SurfaceView;
@@ -37,7 +35,7 @@ import com.google.android.exoplayer2.source.TrackGroupArray;
 import com.google.android.exoplayer2.text.Cue;
 import com.google.android.exoplayer2.text.TextOutput;
 import com.google.android.exoplayer2.trackselection.TrackSelectionArray;
-import com.google.android.exoplayer2.util.MutableFlags;
+import com.google.android.exoplayer2.util.ExoFlags;
 import com.google.android.exoplayer2.util.Util;
 import com.google.android.exoplayer2.video.VideoFrameMetadataListener;
 import com.google.android.exoplayer2.video.VideoListener;
@@ -664,17 +662,27 @@ public interface Player {
   }
 
   /** A set of {@link EventFlags}. */
-  final class Events extends MutableFlags {
+  final class Events {
+
+    private final ExoFlags flags;
+
+    /**
+     * Creates an instance.
+     *
+     * @param flags The {@link ExoFlags} containing the {@link EventFlags} in the set.
+     */
+    public Events(ExoFlags flags) {
+      this.flags = flags;
+    }
+
     /**
      * Returns whether the given event occurred.
      *
      * @param event The {@link EventFlags event}.
      * @return Whether the event occurred.
      */
-    @Override
     public boolean contains(@EventFlags int event) {
-      // Overridden to add IntDef compiler enforcement and new JavaDoc.
-      return super.contains(event);
+      return flags.contains(event);
     }
 
     /**
@@ -683,10 +691,13 @@ public interface Player {
      * @param events The {@link EventFlags events}.
      * @return Whether any of the events occurred.
      */
-    @Override
     public boolean containsAny(@EventFlags int... events) {
-      // Overridden to add IntDef compiler enforcement and new JavaDoc.
-      return super.containsAny(events);
+      return flags.containsAny(events);
+    }
+
+    /** Returns the number of events in the set. */
+    public int size() {
+      return flags.size();
     }
 
     /**
@@ -698,11 +709,9 @@ public interface Player {
      * @param index The index. Must be between 0 (inclusive) and {@link #size()} (exclusive).
      * @return The {@link EventFlags event} at the given index.
      */
-    @Override
     @EventFlags
     public int get(int index) {
-      // Overridden to add IntDef compiler enforcement and new JavaDoc.
-      return super.get(index);
+      return flags.get(index);
     }
   }
 
@@ -716,18 +725,11 @@ public interface Player {
     /** A builder for {@link Commands} instances. */
     public static final class Builder {
 
-      private final SparseBooleanArray commandsArray;
-
-      private boolean buildCalled;
+      private final ExoFlags.Builder flagsBuilder;
 
       /** Creates a builder. */
       public Builder() {
-        commandsArray = new SparseBooleanArray();
-      }
-
-      /** Creates a builder with the values of the provided {@link Commands}. */
-      private Builder(Commands commands) {
-        this.commandsArray = commands.commandsArray.clone();
+        flagsBuilder = new ExoFlags.Builder();
       }
 
       /**
@@ -738,8 +740,7 @@ public interface Player {
        * @throws IllegalStateException If {@link #build()} has already been called.
        */
       public Builder add(@Command int command) {
-        checkState(!buildCalled);
-        commandsArray.append(command, /* value= */ true);
+        flagsBuilder.add(command);
         return this;
       }
 
@@ -752,39 +753,32 @@ public interface Player {
        * @throws IllegalStateException If {@link #build()} has already been called.
        */
       public Builder addIf(@Command int command, boolean condition) {
-        checkState(!buildCalled);
-        if (condition) {
-          commandsArray.append(command, /* value= */ true);
-        }
+        flagsBuilder.addIf(command, condition);
         return this;
       }
 
-      /** Builds a {@link Commands} instance. */
+      /**
+       * Builds a {@link Commands} instance.
+       *
+       * @throws IllegalStateException If this method has already been called.
+       */
       public Commands build() {
-        checkState(!buildCalled);
-        buildCalled = true;
-        return new Commands(commandsArray);
+        return new Commands(flagsBuilder.build());
       }
     }
 
     /** An empty set of commands. */
-    public static final Commands EMPTY = new Commands.Builder().build();
+    public static final Commands EMPTY = new Builder().build();
 
-    // A SparseBooleanArray is used instead of a Set to avoid auto-boxing the Command values.
-    private final SparseBooleanArray commandsArray;
-
-    private Commands(SparseBooleanArray commandsArray) {
-      this.commandsArray = commandsArray;
-    }
+    private final ExoFlags flags;
 
-    /** Returns a {@link Commands.Builder} initialized with the values of this instance. */
-    public Builder buildUpon() {
-      return new Builder(this);
+    private Commands(ExoFlags flags) {
+      this.flags = flags;
     }
 
     /** Returns whether the set of commands contains the specified {@link Command}. */
     public boolean contains(@Command int command) {
-      return commandsArray.get(command);
+      return flags.contains(command);
     }
 
     @Override
@@ -796,12 +790,12 @@ public interface Player {
         return false;
       }
       Commands commands = (Commands) obj;
-      return this.commandsArray.equals(commands.commandsArray);
+      return flags.equals(commands.flags);
     }
 
     @Override
     public int hashCode() {
-      return commandsArray.hashCode();
+      return flags.hashCode();
     }
   }
 

library/common/src/main/java/com/google/android/exoplayer2/util/MutableFlags.java → library/common/src/main/java/com/google/android/exoplayer2/util/ExoFlags.java

@@ -15,6 +15,8 @@
  */
 package com.google.android.exoplayer2.util;
 
+import static com.google.android.exoplayer2.util.Assertions.checkState;
+
 import android.util.SparseBooleanArray;
 import androidx.annotation.Nullable;
 
@@ -23,28 +25,68 @@ import androidx.annotation.Nullable;
  *
  * <p>Intended for usages where the number of flags may exceed 32 and can no longer be represented
  * by an IntDef.
+ *
+ * <p>Instances are immutable.
  */
-public class MutableFlags {
+public final class ExoFlags {
 
-  private final SparseBooleanArray flags;
+  /** A builder for {@link ExoFlags} instances. */
+  public static final class Builder {
 
-  /** Creates the set of flags. */
-  public MutableFlags() {
-    flags = new SparseBooleanArray();
-  }
+    private final SparseBooleanArray flags;
+
+    private boolean buildCalled;
+
+    /** Creates a builder. */
+    public Builder() {
+      flags = new SparseBooleanArray();
+    }
+
+    /**
+     * Adds a flag.
+     *
+     * @param flag A flag.
+     * @return This builder.
+     * @throws IllegalStateException If {@link #build()} has already been called.
+     */
+    public Builder add(int flag) {
+      checkState(!buildCalled);
+      flags.append(flag, /* value= */ true);
+      return this;
+    }
 
-  /** Clears all previously set flags. */
-  public void clear() {
-    flags.clear();
+    /**
+     * Adds a flag if the provided condition is true. Does nothing otherwise.
+     *
+     * @param flag A flag.
+     * @param condition A condition.
+     * @return This builder.
+     * @throws IllegalStateException If {@link #build()} has already been called.
+     */
+    public Builder addIf(int flag, boolean condition) {
+      if (condition) {
+        return add(flag);
+      }
+      return this;
+    }
+
+    /**
+     * Builds an {@link ExoFlags} instance.
+     *
+     * @throws IllegalStateException If this method has already been called.
+     */
+    public ExoFlags build() {
+      checkState(!buildCalled);
+      buildCalled = true;
+      return new ExoFlags(flags);
+    }
   }
 
-  /**
-   * Adds a flag to the set.
-   *
-   * @param flag The flag to add.
-   */
-  public void add(int flag) {
-    flags.append(flag, /* value= */ true);
+  // A SparseBooleanArray is used instead of a Set to avoid auto-boxing the flag values.
+  private final SparseBooleanArray flags;
+
+  private ExoFlags(SparseBooleanArray flags) {
+    this.flags = flags;
   }
 
   /**
@@ -94,10 +136,10 @@ public class MutableFlags {
     if (this == o) {
       return true;
     }
-    if (!(o instanceof MutableFlags)) {
+    if (!(o instanceof ExoFlags)) {
       return false;
     }
-    MutableFlags that = (MutableFlags) o;
+    ExoFlags that = (ExoFlags) o;
     return flags.equals(that.flags);
   }
 

library/common/src/main/java/com/google/android/exoplayer2/util/ListenerSet.java

@@ -20,7 +20,6 @@ import android.os.Message;
 import androidx.annotation.CheckResult;
 import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
-import com.google.common.base.Supplier;
 import java.util.ArrayDeque;
 import java.util.concurrent.CopyOnWriteArraySet;
 import javax.annotation.Nonnull;
@@ -35,9 +34,8 @@ import javax.annotation.Nonnull;
  * was enqueued and haven't been removed since.
  *
  * @param <T> The listener type.
- * @param <E> The {@link MutableFlags} type used to indicate which events occurred.
  */
-public final class ListenerSet<T, E extends MutableFlags> {
+public final class ListenerSet<T> {
 
   /**
    * An event sent to a listener.
@@ -55,17 +53,17 @@ public final class ListenerSet<T, E extends MutableFlags> {
    * iteration were handled by the listener.
    *
    * @param <T> The listener type.
-   * @param <E> The {@link MutableFlags} type used to indicate which events occurred.
    */
-  public interface IterationFinishedEvent<T, E extends MutableFlags> {
+  public interface IterationFinishedEvent<T> {
 
     /**
      * Invokes the iteration finished event.
      *
      * @param listener The listener to invoke the event on.
-     * @param eventFlags The combined event flags of all events sent in this iteration.
+     * @param eventFlags The combined event {@link ExoFlags flags} of all events sent in this
+     *     iteration.
      */
-    void invoke(T listener, E eventFlags);
+    void invoke(T listener, ExoFlags eventFlags);
   }
 
   private static final int MSG_ITERATION_FINISHED = 0;
@@ -73,9 +71,8 @@ public final class ListenerSet<T, E extends MutableFlags> {
 
   private final Clock clock;
   private final HandlerWrapper handler;
-  private final Supplier<E> eventFlagsSupplier;
-  private final IterationFinishedEvent<T, E> iterationFinishedEvent;
-  private final CopyOnWriteArraySet<ListenerHolder<T, E>> listeners;
+  private final IterationFinishedEvent<T> iterationFinishedEvent;
+  private final CopyOnWriteArraySet<ListenerHolder<T>> listeners;
   private final ArrayDeque<Runnable> flushingEvents;
   private final ArrayDeque<Runnable> queuedEvents;
 
@@ -87,33 +84,24 @@ public final class ListenerSet<T, E extends MutableFlags> {
    * @param looper A {@link Looper} used to call listeners on. The same {@link Looper} must be used
    *     to call all other methods of this class.
    * @param clock A {@link Clock}.
-   * @param eventFlagsSupplier A {@link Supplier} for new instances of {@link E the event flags
-   *     type}.
    * @param iterationFinishedEvent An {@link IterationFinishedEvent} sent when all other events sent
    *     during one {@link Looper} message queue iteration were handled by the listeners.
    */
-  public ListenerSet(
-      Looper looper,
-      Clock clock,
-      Supplier<E> eventFlagsSupplier,
-      IterationFinishedEvent<T, E> iterationFinishedEvent) {
+  public ListenerSet(Looper looper, Clock clock, IterationFinishedEvent<T> iterationFinishedEvent) {
     this(
         /* listeners= */ new CopyOnWriteArraySet<>(),
         looper,
         clock,
-        eventFlagsSupplier,
         iterationFinishedEvent);
   }
 
   private ListenerSet(
-      CopyOnWriteArraySet<ListenerHolder<T, E>> listeners,
+      CopyOnWriteArraySet<ListenerHolder<T>> listeners,
       Looper looper,
       Clock clock,
-      Supplier<E> eventFlagsSupplier,
-      IterationFinishedEvent<T, E> iterationFinishedEvent) {
+      IterationFinishedEvent<T> iterationFinishedEvent) {
     this.clock = clock;
     this.listeners = listeners;
-    this.eventFlagsSupplier = eventFlagsSupplier;
     this.iterationFinishedEvent = iterationFinishedEvent;
     flushingEvents = new ArrayDeque<>();
     queuedEvents = new ArrayDeque<>();
@@ -132,9 +120,8 @@ public final class ListenerSet<T, E extends MutableFlags> {
    * @return The copied listener set.
    */
   @CheckResult
-  public ListenerSet<T, E> copy(
-      Looper looper, IterationFinishedEvent<T, E> iterationFinishedEvent) {
-    return new ListenerSet<>(listeners, looper, clock, eventFlagsSupplier, iterationFinishedEvent);
+  public ListenerSet<T> copy(Looper looper, IterationFinishedEvent<T> iterationFinishedEvent) {
+    return new ListenerSet<>(listeners, looper, clock, iterationFinishedEvent);
   }
 
   /**
@@ -149,7 +136,7 @@ public final class ListenerSet<T, E extends MutableFlags> {
       return;
     }
     Assertions.checkNotNull(listener);
-    listeners.add(new ListenerHolder<>(listener, eventFlagsSupplier));
+    listeners.add(new ListenerHolder<>(listener));
   }
 
   /**
@@ -160,7 +147,7 @@ public final class ListenerSet<T, E extends MutableFlags> {
    * @param listener The listener to be removed.
    */
   public void remove(T listener) {
-    for (ListenerHolder<T, E> listenerHolder : listeners) {
+    for (ListenerHolder<T> listenerHolder : listeners) {
       if (listenerHolder.listener.equals(listener)) {
         listenerHolder.release(iterationFinishedEvent);
         listeners.remove(listenerHolder);
@@ -176,11 +163,10 @@ public final class ListenerSet<T, E extends MutableFlags> {
    * @param event The event.
    */
   public void queueEvent(int eventFlag, Event<T> event) {
-    CopyOnWriteArraySet<ListenerHolder<T, E>> listenerSnapshot =
-        new CopyOnWriteArraySet<>(listeners);
+    CopyOnWriteArraySet<ListenerHolder<T>> listenerSnapshot = new CopyOnWriteArraySet<>(listeners);
     queuedEvents.add(
         () -> {
-          for (ListenerHolder<T, E> holder : listenerSnapshot) {
+          for (ListenerHolder<T> holder : listenerSnapshot) {
             holder.invoke(eventFlag, event);
           }
         });
@@ -226,7 +212,7 @@ public final class ListenerSet<T, E extends MutableFlags> {
    * <p>This will ensure no events are sent to any listener after this method has been called.
    */
   public void release() {
-    for (ListenerHolder<T, E> listenerHolder : listeners) {
+    for (ListenerHolder<T> listenerHolder : listeners) {
       listenerHolder.release(iterationFinishedEvent);
     }
     listeners.clear();
@@ -249,8 +235,8 @@ public final class ListenerSet<T, E extends MutableFlags> {
 
   private boolean handleMessage(Message message) {
     if (message.what == MSG_ITERATION_FINISHED) {
-      for (ListenerHolder<T, E> holder : listeners) {
-        holder.iterationFinished(eventFlagsSupplier, iterationFinishedEvent);
+      for (ListenerHolder<T> holder : listeners) {
+        holder.iterationFinished(iterationFinishedEvent);
         if (handler.hasMessages(MSG_ITERATION_FINISHED)) {
           // The invocation above triggered new events (and thus scheduled a new message). We need
           // to stop here because this new message will take care of informing every listener about
@@ -268,45 +254,44 @@ public final class ListenerSet<T, E extends MutableFlags> {
     return true;
   }
 
-  private static final class ListenerHolder<T, E extends MutableFlags> {
+  private static final class ListenerHolder<T> {
 
     @Nonnull public final T listener;
 
-    private E eventsFlags;
+    private ExoFlags.Builder flagsBuilder;
     private boolean needsIterationFinishedEvent;
     private boolean released;
 
-    public ListenerHolder(@Nonnull T listener, Supplier<E> eventFlagSupplier) {
+    public ListenerHolder(@Nonnull T listener) {
       this.listener = listener;
-      this.eventsFlags = eventFlagSupplier.get();
+      this.flagsBuilder = new ExoFlags.Builder();
     }
 
-    public void release(IterationFinishedEvent<T, E> event) {
+    public void release(IterationFinishedEvent<T> event) {
       released = true;
       if (needsIterationFinishedEvent) {
-        event.invoke(listener, eventsFlags);
+        event.invoke(listener, flagsBuilder.build());
       }
     }
 
     public void invoke(int eventFlag, Event<T> event) {
       if (!released) {
         if (eventFlag != C.INDEX_UNSET) {
-          eventsFlags.add(eventFlag);
+          flagsBuilder.add(eventFlag);
         }
         needsIterationFinishedEvent = true;
         event.invoke(listener);
       }
     }
 
-    public void iterationFinished(
-        Supplier<E> eventFlagSupplier, IterationFinishedEvent<T, E> event) {
+    public void iterationFinished(IterationFinishedEvent<T> event) {
       if (!released && needsIterationFinishedEvent) {
         // Reset flags before invoking the listener to ensure we keep all new flags that are set by
         // recursive events triggered from this callback.
-        E flagToNotify = eventsFlags;
-        eventsFlags = eventFlagSupplier.get();
+        ExoFlags flagsToNotify = flagsBuilder.build();
+        flagsBuilder = new ExoFlags.Builder();
         needsIterationFinishedEvent = false;
-        event.invoke(listener, flagToNotify);
+        event.invoke(listener, flagsToNotify);
       }
     }
 
@@ -318,7 +303,7 @@ public final class ListenerSet<T, E extends MutableFlags> {
       if (other == null || getClass() != other.getClass()) {
         return false;
       }
-      return listener.equals(((ListenerHolder<?, ?>) other).listener);
+      return listener.equals(((ListenerHolder<?>) other).listener);
     }
 
     @Override

library/core/src/test/java/com/google/android/exoplayer2/util/MutableFlagsTest.java → library/common/src/test/java/com/google/android/exoplayer2/util/ExoFlagsTest.java

@@ -24,13 +24,13 @@ import java.util.List;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
-/** Unit test for {@link MutableFlags}. */
+/** Unit test for {@link ExoFlags}. */
 @RunWith(AndroidJUnit4.class)
-public final class MutableFlagsTest {
+public final class ExoFlagsTest {
 
   @Test
   public void contains_withoutAdd_returnsFalseForAllValues() {
-    MutableFlags flags = new MutableFlags();
+    ExoFlags flags = new ExoFlags.Builder().build();
 
     assertThat(flags.contains(/* flag= */ -1234)).isFalse();
     assertThat(flags.contains(/* flag= */ 0)).isFalse();
@@ -40,12 +40,13 @@ public final class MutableFlagsTest {
 
   @Test
   public void contains_afterAdd_returnsTrueForAddedValues() {
-    MutableFlags flags = new MutableFlags();
-
-    flags.add(/* flag= */ -1234);
-    flags.add(/* flag= */ 0);
-    flags.add(/* flag= */ 2);
-    flags.add(/* flag= */ Integer.MAX_VALUE);
+    ExoFlags flags =
+        new ExoFlags.Builder()
+            .add(/* flag= */ -1234)
+            .add(/* flag= */ 0)
+            .add(/* flag= */ 2)
+            .add(/* flag= */ Integer.MAX_VALUE)
+            .build();
 
     assertThat(flags.contains(/* flag= */ -1235)).isFalse();
     assertThat(flags.contains(/* flag= */ -1234)).isTrue();
@@ -57,79 +58,94 @@ public final class MutableFlagsTest {
   }
 
   @Test
-  public void contains_afterClear_returnsFalseForAllValues() {
-    MutableFlags flags = new MutableFlags();
-    flags.add(/* flag= */ -1234);
-    flags.add(/* flag= */ 0);
-    flags.add(/* flag= */ 2);
-    flags.add(/* flag= */ Integer.MAX_VALUE);
-
-    flags.clear();
+  public void contains_afterAddIf_returnsTrueForAddedValues() {
+    ExoFlags flags =
+        new ExoFlags.Builder()
+            .addIf(/* flag= */ -1234, /* condition= */ true)
+            .addIf(/* flag= */ 0, /* condition= */ false)
+            .addIf(/* flag= */ 2, /* condition= */ true)
+            .addIf(/* flag= */ Integer.MAX_VALUE, /* condition= */ false)
+            .build();
 
-    assertThat(flags.contains(/* flag= */ -1234)).isFalse();
+    assertThat(flags.contains(/* flag= */ -1235)).isFalse();
+    assertThat(flags.contains(/* flag= */ -1234)).isTrue();
     assertThat(flags.contains(/* flag= */ 0)).isFalse();
-    assertThat(flags.contains(/* flag= */ 2)).isFalse();
+    assertThat(flags.contains(/* flag= */ 1)).isFalse();
+    assertThat(flags.contains(/* flag= */ 2)).isTrue();
+    assertThat(flags.contains(/* flag= */ Integer.MAX_VALUE - 1)).isFalse();
     assertThat(flags.contains(/* flag= */ Integer.MAX_VALUE)).isFalse();
   }
 
   @Test
-  public void size_withoutAdd_returnsZero() {
-    MutableFlags flags = new MutableFlags();
+  public void containsAny_withoutAdd_returnsFalseForAllValues() {
+    ExoFlags flags = new ExoFlags.Builder().build();
 
-    assertThat(flags.size()).isEqualTo(0);
+    assertThat(flags.containsAny(/* flags...= */ -1234, 0, 2, Integer.MAX_VALUE)).isFalse();
   }
 
   @Test
-  public void size_afterAdd_returnsNumberUniqueOfElements() {
-    MutableFlags flags = new MutableFlags();
+  public void containsAny_afterAdd_returnsTrueForAddedValues() {
+    ExoFlags flags =
+        new ExoFlags.Builder()
+            .add(/* flag= */ -1234)
+            .add(/* flag= */ 0)
+            .add(/* flag= */ 2)
+            .add(/* flag= */ Integer.MAX_VALUE)
+            .build();
+
+    assertThat(
+            flags.containsAny(
+                /* flags...= */ -1235, -1234, 0, 1, 2, Integer.MAX_VALUE - 1, Integer.MAX_VALUE))
+        .isTrue();
+    assertThat(flags.containsAny(/* flags...= */ -1235, 1, Integer.MAX_VALUE - 1)).isFalse();
+  }
 
-    flags.add(/* flag= */ 0);
-    flags.add(/* flag= */ 0);
-    flags.add(/* flag= */ 0);
-    flags.add(/* flag= */ 123);
-    flags.add(/* flag= */ 123);
+  @Test
+  public void size_withoutAdd_returnsZero() {
+    ExoFlags flags = new ExoFlags.Builder().build();
 
-    assertThat(flags.size()).isEqualTo(2);
+    assertThat(flags.size()).isEqualTo(0);
   }
 
   @Test
-  public void size_afterClear_returnsZero() {
-    MutableFlags flags = new MutableFlags();
-
-    flags.add(/* flag= */ 0);
-    flags.add(/* flag= */ 123);
-    flags.clear();
+  public void size_afterAdd_returnsNumberUniqueOfElements() {
+    ExoFlags flags =
+        new ExoFlags.Builder()
+            .add(/* flag= */ 0)
+            .add(/* flag= */ 0)
+            .add(/* flag= */ 0)
+            .add(/* flag= */ 123)
+            .add(/* flag= */ 123)
+            .build();
 
-    assertThat(flags.size()).isEqualTo(0);
+    assertThat(flags.size()).isEqualTo(2);
   }
 
   @Test
   public void get_withNegativeIndex_throwsIllegalArgumentException() {
-    MutableFlags flags = new MutableFlags();
+    ExoFlags flags = new ExoFlags.Builder().build();
 
     assertThrows(IllegalArgumentException.class, () -> flags.get(/* index= */ -1));
   }
 
   @Test
   public void get_withIndexExceedingSize_throwsIllegalArgumentException() {
-    MutableFlags flags = new MutableFlags();
-
-    flags.add(/* flag= */ 0);
-    flags.add(/* flag= */ 123);
+    ExoFlags flags = new ExoFlags.Builder().add(/* flag= */ 0).add(/* flag= */ 123).build();
 
     assertThrows(IllegalArgumentException.class, () -> flags.get(/* index= */ 2));
   }
 
   @Test
   public void get_afterAdd_returnsAllUniqueValues() {
-    MutableFlags flags = new MutableFlags();
-
-    flags.add(/* flag= */ 0);
-    flags.add(/* flag= */ 0);
-    flags.add(/* flag= */ 0);
-    flags.add(/* flag= */ 123);
-    flags.add(/* flag= */ 123);
-    flags.add(/* flag= */ 456);
+    ExoFlags flags =
+        new ExoFlags.Builder()
+            .add(/* flag= */ 0)
+            .add(/* flag= */ 0)
+            .add(/* flag= */ 0)
+            .add(/* flag= */ 123)
+            .add(/* flag= */ 123)
+            .add(/* flag= */ 456)
+            .build();
 
     List<Integer> values = new ArrayList<>();
     for (int i = 0; i < flags.size(); i++) {

library/core/src/main/java/com/google/android/exoplayer2/ExoPlayerImpl.java

@@ -71,7 +71,7 @@ import java.util.List;
   private final HandlerWrapper playbackInfoUpdateHandler;
   private final ExoPlayerImplInternal.PlaybackInfoUpdateListener playbackInfoUpdateListener;
   private final ExoPlayerImplInternal internalPlayer;
-  private final ListenerSet<Player.EventListener, Player.Events> listeners;
+  private final ListenerSet<Player.EventListener> listeners;
   private final Timeline.Period period;
   private final List<MediaSourceHolderSnapshot> mediaSourceHolderSnapshots;
   private final boolean useLazyPreparation;
@@ -165,8 +165,7 @@ import java.util.List;
         new ListenerSet<>(
             applicationLooper,
             clock,
-            Player.Events::new,
-            (listener, eventFlags) -> listener.onEvents(playerForListeners, eventFlags));
+            (listener, flags) -> listener.onEvents(playerForListeners, new Events(flags)));
     mediaSourceHolderSnapshots = new ArrayList<>();
     shuffleOrder = new ShuffleOrder.DefaultShuffleOrder(/* length= */ 0);
     emptyTrackSelectorResult =

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

@@ -78,7 +78,7 @@ public class AnalyticsCollector
   private final MediaPeriodQueueTracker mediaPeriodQueueTracker;
   private final SparseArray<EventTime> eventTimes;
 
-  private ListenerSet<AnalyticsListener, AnalyticsListener.Events> listeners;
+  private ListenerSet<AnalyticsListener> listeners;
   private @MonotonicNonNull Player player;
   private boolean isSeeking;
 
@@ -89,12 +89,7 @@ public class AnalyticsCollector
    */
   public AnalyticsCollector(Clock clock) {
     this.clock = checkNotNull(clock);
-    listeners =
-        new ListenerSet<>(
-            Util.getCurrentOrMainLooper(),
-            clock,
-            AnalyticsListener.Events::new,
-            (listener, eventFlags) -> {});
+    listeners = new ListenerSet<>(Util.getCurrentOrMainLooper(), clock, (listener, flags) -> {});
     period = new Period();
     window = new Window();
     mediaPeriodQueueTracker = new MediaPeriodQueueTracker(period);
@@ -137,10 +132,8 @@ public class AnalyticsCollector
     listeners =
         listeners.copy(
             looper,
-            (listener, events) -> {
-              events.setEventTimes(eventTimes);
-              listener.onEvents(player, events);
-            });
+            (listener, flags) ->
+                listener.onEvents(player, new AnalyticsListener.Events(flags, eventTimes)));
   }
 
   /**

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

@@ -47,7 +47,7 @@ import com.google.android.exoplayer2.source.MediaLoadData;
 import com.google.android.exoplayer2.source.MediaSource.MediaPeriodId;
 import com.google.android.exoplayer2.source.TrackGroupArray;
 import com.google.android.exoplayer2.trackselection.TrackSelectionArray;
-import com.google.android.exoplayer2.util.MutableFlags;
+import com.google.android.exoplayer2.util.ExoFlags;
 import com.google.common.base.Objects;
 import java.io.IOException;
 import java.lang.annotation.Documented;
@@ -70,13 +70,27 @@ import java.util.List;
 public interface AnalyticsListener {
 
   /** A set of {@link EventFlags}. */
-  final class Events extends MutableFlags {
+  final class Events {
 
+    private final ExoFlags flags;
     private final SparseArray<EventTime> eventTimes;
 
-    /** Creates the set of event flags. */
-    public Events() {
-      eventTimes = new SparseArray<>(/* initialCapacity= */ 0);
+    /**
+     * Creates an instance.
+     *
+     * @param flags The {@link ExoFlags} containing the {@link EventFlags} in the set.
+     * @param eventTimes A map from {@link EventFlags} to {@link EventTime}. Must at least contain
+     *     all the events recorded in {@code flags}. Events that are not recorded in {@code flags}
+     *     are ignored.
+     */
+    public Events(ExoFlags flags, SparseArray<EventTime> eventTimes) {
+      this.flags = flags;
+      SparseArray<EventTime> flagsToTimes = new SparseArray<>(/* initialCapacity= */ flags.size());
+      for (int i = 0; i < flags.size(); i++) {
+        @EventFlags int eventFlag = flags.get(i);
+        flagsToTimes.append(eventFlag, checkNotNull(eventTimes.get(eventFlag)));
+      }
+      this.eventTimes = flagsToTimes;
     }
 
     /**
@@ -90,29 +104,13 @@ public interface AnalyticsListener {
     }
 
     /**
-     * Sets the {@link EventTime} values for events recorded in this set.
-     *
-     * @param eventTimes A map from {@link EventFlags} to {@link EventTime}. Must at least contain
-     *     all the events recorded in this set.
-     */
-    public void setEventTimes(SparseArray<EventTime> eventTimes) {
-      this.eventTimes.clear();
-      for (int i = 0; i < size(); i++) {
-        @EventFlags int eventFlag = get(i);
-        this.eventTimes.append(eventFlag, checkNotNull(eventTimes.get(eventFlag)));
-      }
-    }
-
-    /**
      * Returns whether the given event occurred.
      *
      * @param event The {@link EventFlags event}.
      * @return Whether the event occurred.
      */
-    @Override
     public boolean contains(@EventFlags int event) {
-      // Overridden to add IntDef compiler enforcement and new JavaDoc.
-      return super.contains(event);
+      return flags.contains(event);
     }
 
     /**
@@ -121,10 +119,13 @@ public interface AnalyticsListener {
      * @param events The {@link EventFlags events}.
      * @return Whether any of the events occurred.
      */
-    @Override
     public boolean containsAny(@EventFlags int... events) {
-      // Overridden to add IntDef compiler enforcement and new JavaDoc.
-      return super.containsAny(events);
+      return flags.containsAny(events);
+    }
+
+    /** Returns the number of events in the set. */
+    public int size() {
+      return flags.size();
     }
 
     /**
@@ -136,11 +137,9 @@ public interface AnalyticsListener {
      * @param index The index. Must be between 0 (inclusive) and {@link #size()} (exclusive).
      * @return The {@link EventFlags event} at the given index.
      */
-    @Override
     @EventFlags
     public int get(int index) {
-      // Overridden to add IntDef compiler enforcement and new JavaDoc.
-      return super.get(index);
+      return flags.get(index);
     }
   }