1 /* 2 * Copyright (C) 2018 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 17 package com.android.car; 18 19 import android.annotation.Nullable; 20 import android.annotation.RawRes; 21 import android.content.Context; 22 23 import java.io.BufferedReader; 24 import java.io.IOException; 25 import java.io.InputStream; 26 import java.io.InputStreamReader; 27 import java.io.Reader; 28 29 /** 30 * An implementation of {@link com.android.car.CarConfigurationService.JsonReader} that will 31 * parse a JSON file on the system that is mapped to {@code R.raw.car_config}. 32 */ 33 public class JsonReaderImpl implements CarConfigurationService.JsonReader { 34 private static final int BUF_SIZE = 0x1000; // 2K chars (4K bytes) 35 private static final String JSON_FILE_ENCODING = "UTF-8"; 36 37 /** 38 * Takes a resource file that is considered to be a JSON file and parses it into a String that 39 * is returned. 40 * 41 * @param resId The resource id pointing to the json file. 42 * @return A {@code String} representing the file contents, or {@code null} if 43 */ 44 @Override 45 @Nullable 46 public String jsonFileToString(Context context, @RawRes int resId) { 47 InputStream is = context.getResources().openRawResource(resId); 48 49 // Note: this "try" will close the Reader, thus closing the associated InputStreamReader 50 // and InputStream. 51 try (Reader reader = new BufferedReader(new InputStreamReader(is, JSON_FILE_ENCODING))) { 52 char[] buffer = new char[BUF_SIZE]; 53 StringBuilder stringBuilder = new StringBuilder(); 54 55 int bufferedContent; 56 while ((bufferedContent = reader.read(buffer)) != -1) { 57 stringBuilder.append(buffer, /* offset= */ 0, bufferedContent); 58 } 59 60 return stringBuilder.toString(); 61 } catch (IOException e) { 62 return null; 63 } 64 } 65 } 66
