BaseDataSource.java
/*
* Copyright (C) 2018 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.datasource;
import static androidx.media3.common.util.Assertions.checkNotNull;
import static androidx.media3.common.util.Util.castNonNull;
import androidx.annotation.Nullable;
import androidx.media3.common.util.UnstableApi;
import java.util.ArrayList;
/**
* Base {@link DataSource} implementation to keep a list of {@link TransferListener}s.
*
* <p>Subclasses must call {@link #transferInitializing(DataSpec)}, {@link
* #transferStarted(DataSpec)}, {@link #bytesTransferred(int)}, and {@link #transferEnded()} to
* inform listeners of data transfers.
*/
@UnstableApi
public abstract class BaseDataSource implements DataSource {
private final boolean isNetwork;
private final ArrayList<TransferListener> listeners;
private int listenerCount;
@Nullable private DataSpec dataSpec;
/**
* Creates base data source.
*
* @param isNetwork Whether the data source loads data through a network.
*/
protected BaseDataSource(boolean isNetwork) {
this.isNetwork = isNetwork;
this.listeners = new ArrayList<>(/* initialCapacity= */ 1);
}
@Override
public final void addTransferListener(TransferListener transferListener) {
checkNotNull(transferListener);
if (!listeners.contains(transferListener)) {
listeners.add(transferListener);
listenerCount++;
}
}
/**
* Notifies listeners that data transfer for the specified {@link DataSpec} is being initialized.
*
* @param dataSpec {@link DataSpec} describing the data for initializing transfer.
*/
protected final void transferInitializing(DataSpec dataSpec) {
for (int i = 0; i < listenerCount; i++) {
listeners.get(i).onTransferInitializing(/* source= */ this, dataSpec, isNetwork);
}
}
/**
* Notifies listeners that data transfer for the specified {@link DataSpec} started.
*
* @param dataSpec {@link DataSpec} describing the data being transferred.
*/
protected final void transferStarted(DataSpec dataSpec) {
this.dataSpec = dataSpec;
for (int i = 0; i < listenerCount; i++) {
listeners.get(i).onTransferStart(/* source= */ this, dataSpec, isNetwork);
}
}
/**
* Notifies listeners that bytes were transferred.
*
* @param bytesTransferred The number of bytes transferred since the previous call to this method
* (or if the first call, since the transfer was started).
*/
protected final void bytesTransferred(int bytesTransferred) {
DataSpec dataSpec = castNonNull(this.dataSpec);
for (int i = 0; i < listenerCount; i++) {
listeners
.get(i)
.onBytesTransferred(/* source= */ this, dataSpec, isNetwork, bytesTransferred);
}
}
/** Notifies listeners that a transfer ended. */
protected final void transferEnded() {
DataSpec dataSpec = castNonNull(this.dataSpec);
for (int i = 0; i < listenerCount; i++) {
listeners.get(i).onTransferEnd(/* source= */ this, dataSpec, isNetwork);
}
this.dataSpec = null;
}
}