Make factories return specific types

PiperOrigin-RevId: 272614917

extensions/rtmp/src/main/java/com/google/android/exoplayer2/ext/rtmp/RtmpDataSourceFactory.java

@@ -37,7 +37,7 @@ public final class RtmpDataSourceFactory implements DataSource.Factory {
   }
 
   @Override
-  public DataSource createDataSource() {
+  public RtmpDataSource createDataSource() {
     RtmpDataSource dataSource = new RtmpDataSource();
     if (listener != null) {
       dataSource.addTransferListener(listener);

library/core/src/main/java/com/google/android/exoplayer2/upstream/FileDataSourceFactory.java

@@ -33,7 +33,7 @@ public final class FileDataSourceFactory implements DataSource.Factory {
   }
 
   @Override
-  public DataSource createDataSource() {
+  public FileDataSource createDataSource() {
     FileDataSource dataSource = new FileDataSource();
     if (listener != null) {
       dataSource.addTransferListener(listener);

library/core/src/main/java/com/google/android/exoplayer2/upstream/ResolvingDataSource.java

@@ -64,9 +64,7 @@ public final class ResolvingDataSource implements DataSource {
     private final Resolver resolver;
 
     /**
-     * Creates factory for {@link ResolvingDataSource} instances.
-     *
-     * @param upstreamFactory The wrapped {@link DataSource.Factory} handling the resolved {@link
+     * @param upstreamFactory The wrapped {@link DataSource.Factory} for handling resolved {@link
      *     DataSpec DataSpecs}.
      * @param resolver The {@link Resolver} to resolve the {@link DataSpec DataSpecs}.
      */
@@ -76,7 +74,7 @@ public final class ResolvingDataSource implements DataSource {
     }
 
     @Override
-    public DataSource createDataSource() {
+    public ResolvingDataSource createDataSource() {
       return new ResolvingDataSource(upstreamFactory.createDataSource(), resolver);
     }
   }

testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeDataSource.java

@@ -52,7 +52,7 @@ public class FakeDataSource extends BaseDataSource {
     }
 
     @Override
-    public DataSource createDataSource() {
+    public FakeDataSource createDataSource() {
       return new FakeDataSource(fakeDataSet, isNetwork);
     }
   }