Move BasePreloadManager.Listener to a top level PreloadManagerListener

PiperOrigin-RevId: 702351887

RELEASENOTES.md

@@ -22,6 +22,8 @@
         2000 ms respectively.
     *   Add `MediaExtractorCompat`, a new class that provides equivalent
         functionality to platform `MediaExtractor`.
+    *   Move `BasePreloadManager.Listener` to a top level
+        `PreloadManagerListener`.
 *   Transformer:
     *   Update parameters of `VideoFrameProcessor.registerInputStream` and
         `VideoFrameProcessor.Listener.onInputStreamRegistered` to use `Format`.

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/source/preload/BasePreloadManager.java

@@ -62,21 +62,11 @@ public abstract class BasePreloadManager<T> {
     public abstract BasePreloadManager<T> build();
   }
 
-  /** Listener for events in a preload manager. */
-  public interface Listener {
-
-    /** Called when the given {@link MediaItem} has completed preloading. */
-    void onCompleted(MediaItem mediaItem);
-
-    /** Called when an {@linkplain PreloadException error} occurs. */
-    void onError(PreloadException exception);
-  }
-
   private final Object lock;
   protected final Comparator<T> rankingDataComparator;
   private final TargetPreloadStatusControl<T> targetPreloadStatusControl;
   private final MediaSource.Factory mediaSourceFactory;
-  private final ListenerSet<Listener> listeners;
+  private final ListenerSet<PreloadManagerListener> listeners;
   private final Map<MediaItem, MediaSourceHolder> mediaItemMediaSourceHolderMap;
   private final Handler applicationHandler;
 
@@ -103,26 +93,26 @@ public abstract class BasePreloadManager<T> {
   }
 
   /**
-   * Adds a {@link Listener} to listen to the preload events.
+   * Adds a {@link PreloadManagerListener} to listen to the preload events.
    *
    * <p>This method can be called from any thread.
    */
-  public void addListener(Listener listener) {
+  public void addListener(PreloadManagerListener listener) {
     listeners.add(listener);
   }
 
   /**
-   * Removes a {@link Listener}.
+   * Removes a {@link PreloadManagerListener}.
    *
    * @throws IllegalStateException If this method is called from the wrong thread.
    */
-  public void removeListener(Listener listener) {
+  public void removeListener(PreloadManagerListener listener) {
     verifyApplicationThread();
     listeners.remove(listener);
   }
 
   /**
-   * Clears all the {@linkplain Listener listeners}.
+   * Clears all the {@linkplain PreloadManagerListener listeners}.
    *
    * @throws IllegalStateException If this method is called from the wrong thread.
    */

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/source/preload/PreloadManagerListener.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2024 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
+ *
+ *      https://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.source.preload;
+
+import androidx.media3.common.MediaItem;
+import androidx.media3.common.util.UnstableApi;
+
+/**
+ * Listener for events in a preload manager.
+ *
+ * <p>All methods have no-op default implementations to allow selective overrides.
+ */
+@UnstableApi
+public interface PreloadManagerListener {
+
+  /** Called when the given {@link MediaItem} has completed preloading. */
+  default void onCompleted(MediaItem mediaItem) {}
+
+  /** Called when an {@linkplain PreloadException error} occurs. */
+  default void onError(PreloadException exception) {}
+}

libraries/exoplayer/src/test/java/androidx/media3/exoplayer/source/preload/DefaultPreloadManagerTest.java

@@ -902,7 +902,7 @@ public class DefaultPreloadManagerTest {
     preloadThread.quit();
   }
 
-  private static class TestPreloadManagerListener implements BasePreloadManager.Listener {
+  private static class TestPreloadManagerListener implements PreloadManagerListener {
 
     public final List<MediaItem> onCompletedMediaItemRecords;
     public final List<PreloadException> onErrorPreloadExceptionRecords;