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/*
* Copyright (C) 2015 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.android.tv.util;
import android.media.tv.TvTrackInfo;
import java.util.Comparator;
import java.util.List;
/**
* Static utilities for {@link TvTrackInfo}.
*/
public class TvTrackInfoUtils {
/**
* Compares how closely two {@link android.media.tv.TvTrackInfo}s match {@code language}, {@code
* channelCount} and {@code id} in that precedence.
*
* @param id The track id to match.
* @param language The language to match.
* @param channelCount The channel count to match.
* @return -1 if lhs is a worse match, 0 if lhs and rhs match equally and 1 if lhs is a better
* match.
*/
public static Comparator<TvTrackInfo> createComparator(final String id, final String language,
final int channelCount) {
return new Comparator<TvTrackInfo>() {
@Override
public int compare(TvTrackInfo lhs, TvTrackInfo rhs) {
if (lhs == rhs) {
return 0;
}
if (lhs == null) {
return -1;
}
if (rhs == null) {
return 1;
}
// Assumes {@code null} language matches to any language since it means user hasn't
// selected any track before or selected a track without language information.
boolean rhsLangMatch = language == null || Utils.isEqualLanguage(rhs.getLanguage(),
language);
boolean lhsLangMatch = language == null || Utils.isEqualLanguage(lhs.getLanguage(),
language);
if (rhsLangMatch) {
if (lhsLangMatch) {
boolean rhsCountMatch = rhs.getAudioChannelCount() == channelCount;
boolean lhsCountMatch = lhs.getAudioChannelCount() == channelCount;
if (rhsCountMatch) {
if (lhsCountMatch) {
boolean rhsIdMatch = rhs.getId().equals(id);
boolean lhsIdMatch = lhs.getId().equals(id);
if (rhsIdMatch) {
return lhsIdMatch ? 0 : -1;
} else {
return lhsIdMatch ? 1 : 0;
}
} else {
return -1;
}
} else {
return lhsCountMatch ? 1 : 0;
}
} else {
return -1;
}
} else {
return lhsLangMatch ? 1 : 0;
}
}
};
}
/**
* Selects the best TvTrackInfo available or the first if none matches.
*
* @param tracks The tracks to choose from
* @param id The track id to match.
* @param language The language to match.
* @param channelCount The channel count to match.
* @return the best matching track or the first one if none matches.
*/
public static TvTrackInfo getBestTrackInfo(List<TvTrackInfo> tracks, String id, String language,
int channelCount) {
if (tracks == null) {
return null;
}
Comparator<TvTrackInfo> comparator = createComparator(id, language, channelCount);
TvTrackInfo best = null;
for (TvTrackInfo track : tracks) {
if (comparator.compare(track, best) > 0) {
best = track;
}
}
return best;
}
private TvTrackInfoUtils() {
}
}
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