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      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      */
     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                 boolean rhsLangMatch = Utils.isEqualLanguage(rhs.getLanguage(), language);
     54                 boolean lhsLangMatch = Utils.isEqualLanguage(lhs.getLanguage(), language);
     55                 if (rhsLangMatch) {
     56                     if (lhsLangMatch) {
     57                         boolean rhsCountMatch = rhs.getAudioChannelCount() == channelCount;
     58                         boolean lhsCountMatch = lhs.getAudioChannelCount() == channelCount;
     59                         if (rhsCountMatch) {
     60                             if (lhsCountMatch) {
     61                                 boolean rhsIdMatch = rhs.getId().equals(id);
     62                                 boolean lhsIdMatch = lhs.getId().equals(id);
     63                                 if (rhsIdMatch) {
     64                                     return lhsIdMatch ? 0 : -1;
     65                                 } else {
     66                                     return lhsIdMatch ? 1 : 0;
     67                                 }
     68 
     69                             } else {
     70                                 return -1;
     71                             }
     72                         } else {
     73                             return lhsCountMatch ? 1 : 0;
     74                         }
     75                     } else {
     76                         return -1;
     77                     }
     78                 } else {
     79                     return lhsLangMatch ? 1 : 0;
     80                 }
     81             }
     82         };
     83     }
     84 
     85     /**
     86      * Selects the  best TvTrackInfo available or the first if none matches.
     87      *
     88      * @param tracks       The tracks to choose from
     89      * @param id           The track id to match.
     90      * @param language     The language to match.
     91      * @param channelCount The channel count to match.
     92      * @return the best matching track or the first one if none matches.
     93      */
     94     public static TvTrackInfo getBestTrackInfo(List<TvTrackInfo> tracks, String id, String language,
     95             int channelCount) {
     96         if (tracks == null) {
     97             return null;
     98         }
     99         Comparator<TvTrackInfo> comparator = createComparator(id, language, channelCount);
    100         TvTrackInfo best = null;
    101         for (TvTrackInfo track : tracks) {
    102             if (comparator.compare(track, best) > 0) {
    103                 best = track;
    104             }
    105         }
    106         return best;
    107     }
    108 
    109     private TvTrackInfoUtils() {
    110     }
    111 }
    112