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 import java.util.Comparator; 20 import java.util.List; 21 22 /** Static utilities for {@link TvTrackInfo}. */ 23 public class TvTrackInfoUtils { 24 25 /** 26 * Compares how closely two {@link android.media.tv.TvTrackInfo}s match {@code language}, {@code 27 * channelCount} and {@code id} in that precedence. 28 * 29 * @param id The track id to match. 30 * @param language The language to match. 31 * @param channelCount The channel count to match. 32 * @return -1 if lhs is a worse match, 0 if lhs and rhs match equally and 1 if lhs is a better 33 * match. 34 */ createComparator( final String id, final String language, final int channelCount)35 public static Comparator<TvTrackInfo> createComparator( 36 final String id, final String language, final int channelCount) { 37 return new Comparator<TvTrackInfo>() { 38 39 @Override 40 public int compare(TvTrackInfo lhs, TvTrackInfo rhs) { 41 if (lhs == rhs) { 42 return 0; 43 } 44 if (lhs == null) { 45 return -1; 46 } 47 if (rhs == null) { 48 return 1; 49 } 50 // Assumes {@code null} language matches to any language since it means user hasn't 51 // selected any track before or selected a track without language information. 52 boolean lhsLangMatch = 53 language == null || Utils.isEqualLanguage(lhs.getLanguage(), language); 54 boolean rhsLangMatch = 55 language == null || Utils.isEqualLanguage(rhs.getLanguage(), language); 56 if (lhsLangMatch && rhsLangMatch) { 57 boolean lhsCountMatch = 58 lhs.getType() != TvTrackInfo.TYPE_AUDIO 59 || lhs.getAudioChannelCount() == channelCount; 60 boolean rhsCountMatch = 61 rhs.getType() != TvTrackInfo.TYPE_AUDIO 62 || rhs.getAudioChannelCount() == channelCount; 63 if (lhsCountMatch && rhsCountMatch) { 64 return Boolean.compare(lhs.getId().equals(id), rhs.getId().equals(id)); 65 } else { 66 return Boolean.compare(lhsCountMatch, rhsCountMatch); 67 } 68 } else { 69 return Boolean.compare(lhsLangMatch, rhsLangMatch); 70 } 71 } 72 }; 73 } 74 75 /** 76 * Selects the best TvTrackInfo available or the first if none matches. 77 * 78 * @param tracks The tracks to choose from 79 * @param id The track id to match. 80 * @param language The language to match. 81 * @param channelCount The channel count to match. 82 * @return the best matching track or the first one if none matches. 83 */ 84 public static TvTrackInfo getBestTrackInfo( 85 List<TvTrackInfo> tracks, String id, String language, int channelCount) { 86 if (tracks == null) { 87 return null; 88 } 89 Comparator<TvTrackInfo> comparator = createComparator(id, language, channelCount); 90 TvTrackInfo best = null; 91 for (TvTrackInfo track : tracks) { 92 if (comparator.compare(track, best) > 0) { 93 best = track; 94 } 95 } 96 return best; 97 } 98 99 private TvTrackInfoUtils() {} 100 } 101