* Copyright (C) 2016 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 com.google.android.exoplayer2.extractor;
import java.util.ArrayList;
import java.util.List;
/**
* An {@link ExtractorsFactory} that provides an array of extractors for the following formats:
*
* <ul>
* <li>MP4, including M4A ({@link com.google.android.exoplayer2.extractor.mp4.Mp4Extractor})</li>
* <li>fMP4 ({@link com.google.android.exoplayer2.extractor.mp4.FragmentedMp4Extractor})</li>
* <li>Matroska and WebM ({@link com.google.android.exoplayer2.extractor.mkv.MatroskaExtractor})
* </li>
* <li>Ogg Vorbis/FLAC ({@link com.google.android.exoplayer2.extractor.ogg.OggExtractor}</li>
* <li>MP3 ({@link com.google.android.exoplayer2.extractor.mp3.Mp3Extractor})</li>
* <li>AAC ({@link com.google.android.exoplayer2.extractor.ts.AdtsExtractor})</li>
* <li>MPEG TS ({@link com.google.android.exoplayer2.extractor.ts.TsExtractor})</li>
* <li>MPEG PS ({@link com.google.android.exoplayer2.extractor.ts.PsExtractor})</li>
* <li>FLV ({@link com.google.android.exoplayer2.extractor.flv.FlvExtractor})</li>
* <li>WAV ({@link com.google.android.exoplayer2.extractor.wav.WavExtractor})</li>
* <li>FLAC (only available if the FLAC extension is built and included)</li>
* </ul>
*/
public final class DefaultExtractorsFactory implements ExtractorsFactory {
// Lazily initialized default extractor classes in priority order.
private static List<Class<? extends Extractor>> defaultExtractorClasses;
/**
* Creates a new factory for the default extractors.
*/
public DefaultExtractorsFactory() {
synchronized (DefaultExtractorsFactory.class) {
if (defaultExtractorClasses == null) {
// Lazily initialize defaultExtractorClasses.
List<Class<? extends Extractor>> extractorClasses = new ArrayList<>();
// We reference extractors using reflection so that they can be deleted cleanly.
// Class.forName is used so that automated tools like proguard can detect the use of
// reflection (see http://proguard.sourceforge.net/FAQ.html#forname).
try {
extractorClasses.add(
Class.forName("com.google.android.exoplayer2.extractor.mkv.MatroskaExtractor")
.asSubclass(Extractor.class));
} catch (ClassNotFoundException e) {
// Extractor not found.
}
try {
extractorClasses.add(
Class.forName("com.google.android.exoplayer2.extractor.mp4.FragmentedMp4Extractor")
.asSubclass(Extractor.class));
} catch (ClassNotFoundException e) {
// Extractor not found.
}
try {
extractorClasses.add(
Class.forName("com.google.android.exoplayer2.extractor.mp4.Mp4Extractor")
.asSubclass(Extractor.class));
} catch (ClassNotFoundException e) {
// Extractor not found.
}
try {
extractorClasses.add(
Class.forName("com.google.android.exoplayer2.extractor.mp3.Mp3Extractor")
.asSubclass(Extractor.class));
} catch (ClassNotFoundException e) {
// Extractor not found.
}
try {
extractorClasses.add(
Class.forName("com.google.android.exoplayer2.extractor.ts.AdtsExtractor")
.asSubclass(Extractor.class));
} catch (ClassNotFoundException e) {
// Extractor not found.
}
try {
extractorClasses.add(
Class.forName("com.google.android.exoplayer2.extractor.ts.Ac3Extractor")
.asSubclass(Extractor.class));
} catch (ClassNotFoundException e) {
// Extractor not found.
}
try {
extractorClasses.add(
Class.forName("com.google.android.exoplayer2.extractor.ts.TsExtractor")
.asSubclass(Extractor.class));
} catch (ClassNotFoundException e) {
// Extractor not found.
}
try {
extractorClasses.add(
Class.forName("com.google.android.exoplayer2.extractor.flv.FlvExtractor")
.asSubclass(Extractor.class));
} catch (ClassNotFoundException e) {
// Extractor not found.
}
try {
extractorClasses.add(
Class.forName("com.google.android.exoplayer2.extractor.ogg.OggExtractor")
.asSubclass(Extractor.class));
} catch (ClassNotFoundException e) {
// Extractor not found.
}
try {
extractorClasses.add(
Class.forName("com.google.android.exoplayer2.extractor.ts.PsExtractor")
.asSubclass(Extractor.class));
} catch (ClassNotFoundException e) {
// Extractor not found.
}
try {
extractorClasses.add(
Class.forName("com.google.android.exoplayer2.extractor.wav.WavExtractor")
.asSubclass(Extractor.class));
} catch (ClassNotFoundException e) {
// Extractor not found.
}
try {
extractorClasses.add(
Class.forName("com.google.android.exoplayer2.ext.flac.FlacExtractor")
.asSubclass(Extractor.class));
} catch (ClassNotFoundException e) {
// Extractor not found.
}
defaultExtractorClasses = extractorClasses;
}
}
}
@Override
public Extractor[] createExtractors() {
Extractor[] extractors = new Extractor[defaultExtractorClasses.size()];
for (int i = 0; i < extractors.length; i++) {
try {
extractors[i] = defaultExtractorClasses.get(i).getConstructor().newInstance();
} catch (Exception e) {
// Should never happen.
throw new IllegalStateException("Unexpected error creating default extractor", e);
}
}
return extractors;
}
}
Class.forName
https://docs.oracle.com/javase/7/docs/api/java/lang/Class.html#forName(java.lang.String)
http://stackoverflow.com/questions/4612386/what-is-the-difference-between-the-new-operator-and-class-newinstance
http://stackoverflow.com/questions/4612386/what-is-the-difference-between-the-new-operator-and-class-newinstance
asSubclass
getConstructorhttps://docs.oracle.com/javase/7/docs/api/java/lang/Class.html#getConstructor(java.lang.Class...)
newInstance
https://docs.oracle.com/javase/7/docs/api/java/lang/Class.html#newInstance()
