1 /* 2 * Copyright (C) 2015 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 package com.android.tv.util; 17 18 import android.media.tv.TvTrackInfo; 19 20 import java.util.Comparator; 21 import java.util.List; 22 23 /** 24 * Static utilities for {@link TvTrackInfo}. 25 */ 26 public class TvTrackInfoUtils { 27 28 /** 29 * Compares how closely two {@link android.media.tv.TvTrackInfo}s match {@code language}, {@code 30 * channelCount} and {@code id} in that precedence. 31 * 32 * @param id The track id to match. 33 * @param language The language to match. 34 * @param channelCount The channel count to match. 35 * @return -1 if lhs is a worse match, 0 if lhs and rhs match equally and 1 if lhs is a better 36 * match. 37 */ createComparator(final String id, final String language, final int channelCount)38 public static Comparator<TvTrackInfo> createComparator(final String id, final String language, 39 final int channelCount) { 40 return new Comparator<TvTrackInfo>() { 41 42 @Override 43 public int compare(TvTrackInfo lhs, TvTrackInfo rhs) { 44 if (lhs == rhs) { 45 return 0; 46 } 47 if (lhs == null) { 48 return -1; 49 } 50 if (rhs == null) { 51 return 1; 52 } 53 // Assumes {@code null} language matches to any language since it means user hasn't 54 // selected any track before or selected a track without language information. 55 boolean lhsLangMatch = language == null || Utils.isEqualLanguage(lhs.getLanguage(), 56 language); 57 boolean rhsLangMatch = language == null || Utils.isEqualLanguage(rhs.getLanguage(), 58 language); 59 if (lhsLangMatch && rhsLangMatch) { 60 boolean lhsCountMatch = lhs.getType() != TvTrackInfo.TYPE_AUDIO 61 || lhs.getAudioChannelCount() == channelCount; 62 boolean rhsCountMatch = rhs.getType() != TvTrackInfo.TYPE_AUDIO 63 || rhs.getAudioChannelCount() == channelCount; 64 if (lhsCountMatch && rhsCountMatch) { 65 return Boolean.compare(lhs.getId().equals(id), rhs.getId().equals(id)); 66 } else { 67 return Boolean.compare(lhsCountMatch, rhsCountMatch); 68 } 69 } else { 70 return Boolean.compare(lhsLangMatch, rhsLangMatch); 71 } 72 } 73 }; 74 } 75 76 /** 77 * Selects the best TvTrackInfo available or the first if none matches. 78 * 79 * @param tracks The tracks to choose from 80 * @param id The track id to match. 81 * @param language The language to match. 82 * @param channelCount The channel count to match. 83 * @return the best matching track or the first one if none matches. 84 */ 85 public static TvTrackInfo getBestTrackInfo(List<TvTrackInfo> tracks, String id, String language, 86 int channelCount) { 87 if (tracks == null) { 88 return null; 89 } 90 Comparator<TvTrackInfo> comparator = createComparator(id, language, channelCount); 91 TvTrackInfo best = null; 92 for (TvTrackInfo track : tracks) { 93 if (comparator.compare(track, best) > 0) { 94 best = track; 95 } 96 } 97 return best; 98 } 99 100 private TvTrackInfoUtils() { 101 } 102 }