1 /* 2 * Copyright (C) 2011 The Libphonenumber Authors 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.i18n.phonenumbers.geocoding; 18 19 import com.android.i18n.phonenumbers.PhoneNumberUtil; 20 import com.android.i18n.phonenumbers.Phonenumber.PhoneNumber; 21 22 import java.io.ByteArrayOutputStream; 23 import java.io.Externalizable; 24 import java.io.IOException; 25 import java.io.ObjectInput; 26 import java.io.ObjectOutput; 27 import java.io.ObjectOutputStream; 28 import java.util.SortedMap; 29 import java.util.SortedSet; 30 import java.util.logging.Logger; 31 32 /** 33 * A utility that maps phone number prefixes to a string describing the geographical area the prefix 34 * covers. 35 * 36 * @author Shaopeng Jia 37 */ 38 public class AreaCodeMap implements Externalizable { 39 private final PhoneNumberUtil phoneUtil = PhoneNumberUtil.getInstance(); 40 private static final Logger LOGGER = Logger.getLogger(AreaCodeMap.class.getName()); 41 42 private AreaCodeMapStorageStrategy areaCodeMapStorage; 43 44 // @VisibleForTesting 45 AreaCodeMapStorageStrategy getAreaCodeMapStorage() { 46 return areaCodeMapStorage; 47 } 48 49 /** 50 * Creates an empty {@link AreaCodeMap}. The default constructor is necessary for implementing 51 * {@link Externalizable}. The empty map could later be populated by 52 * {@link #readAreaCodeMap(java.util.SortedMap)} or {@link #readExternal(java.io.ObjectInput)}. 53 */ 54 public AreaCodeMap() {} 55 56 /** 57 * Gets the size of the provided area code map storage. The map storage passed-in will be filled 58 * as a result. 59 */ 60 private static int getSizeOfAreaCodeMapStorage(AreaCodeMapStorageStrategy mapStorage, 61 SortedMap<Integer, String> areaCodeMap) throws IOException { 62 mapStorage.readFromSortedMap(areaCodeMap); 63 ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream(); 64 ObjectOutputStream objectOutputStream = new ObjectOutputStream(byteArrayOutputStream); 65 mapStorage.writeExternal(objectOutputStream); 66 objectOutputStream.flush(); 67 int sizeOfStorage = byteArrayOutputStream.size(); 68 objectOutputStream.close(); 69 return sizeOfStorage; 70 } 71 72 private AreaCodeMapStorageStrategy createDefaultMapStorage() { 73 return new DefaultMapStorage(); 74 } 75 76 private AreaCodeMapStorageStrategy createFlyweightMapStorage() { 77 return new FlyweightMapStorage(); 78 } 79 80 /** 81 * Gets the smaller area code map storage strategy according to the provided area code map. It 82 * actually uses (outputs the data to a stream) both strategies and retains the best one which 83 * make this method quite expensive. 84 */ 85 // @VisibleForTesting 86 AreaCodeMapStorageStrategy getSmallerMapStorage(SortedMap<Integer, String> areaCodeMap) { 87 try { 88 AreaCodeMapStorageStrategy flyweightMapStorage = createFlyweightMapStorage(); 89 int sizeOfFlyweightMapStorage = getSizeOfAreaCodeMapStorage(flyweightMapStorage, areaCodeMap); 90 91 AreaCodeMapStorageStrategy defaultMapStorage = createDefaultMapStorage(); 92 int sizeOfDefaultMapStorage = getSizeOfAreaCodeMapStorage(defaultMapStorage, areaCodeMap); 93 94 return sizeOfFlyweightMapStorage < sizeOfDefaultMapStorage 95 ? flyweightMapStorage : defaultMapStorage; 96 } catch (IOException e) { 97 LOGGER.severe(e.getMessage()); 98 return createFlyweightMapStorage(); 99 } 100 } 101 102 /** 103 * Creates an {@link AreaCodeMap} initialized with {@code sortedAreaCodeMap}. Note that the 104 * underlying implementation of this method is expensive thus should not be called by 105 * time-critical applications. 106 * 107 * @param sortedAreaCodeMap a map from phone number prefixes to descriptions of corresponding 108 * geographical areas, sorted in ascending order of the phone number prefixes as integers. 109 */ 110 public void readAreaCodeMap(SortedMap<Integer, String> sortedAreaCodeMap) { 111 areaCodeMapStorage = getSmallerMapStorage(sortedAreaCodeMap); 112 } 113 114 /** 115 * Supports Java Serialization. 116 */ 117 public void readExternal(ObjectInput objectInput) throws IOException { 118 // Read the area code map storage strategy flag. 119 boolean useFlyweightMapStorage = objectInput.readBoolean(); 120 if (useFlyweightMapStorage) { 121 areaCodeMapStorage = new FlyweightMapStorage(); 122 } else { 123 areaCodeMapStorage = new DefaultMapStorage(); 124 } 125 areaCodeMapStorage.readExternal(objectInput); 126 } 127 128 /** 129 * Supports Java Serialization. 130 */ 131 public void writeExternal(ObjectOutput objectOutput) throws IOException { 132 objectOutput.writeBoolean(areaCodeMapStorage instanceof FlyweightMapStorage); 133 areaCodeMapStorage.writeExternal(objectOutput); 134 } 135 136 /** 137 * Returns the description of the geographical area the {@code number} corresponds to. This method 138 * distinguishes the case of an invalid prefix and a prefix for which the name is not available in 139 * the current language. If the description is not available in the current language an empty 140 * string is returned. If no description was found for the provided number, null is returned. 141 * 142 * @param number the phone number to look up 143 * @return the description of the geographical area 144 */ 145 String lookup(PhoneNumber number) { 146 int numOfEntries = areaCodeMapStorage.getNumOfEntries(); 147 if (numOfEntries == 0) { 148 return null; 149 } 150 long phonePrefix = 151 Long.parseLong(number.getCountryCode() + phoneUtil.getNationalSignificantNumber(number)); 152 int currentIndex = numOfEntries - 1; 153 SortedSet<Integer> currentSetOfLengths = areaCodeMapStorage.getPossibleLengths(); 154 while (currentSetOfLengths.size() > 0) { 155 Integer possibleLength = currentSetOfLengths.last(); 156 String phonePrefixStr = String.valueOf(phonePrefix); 157 if (phonePrefixStr.length() > possibleLength) { 158 phonePrefix = Long.parseLong(phonePrefixStr.substring(0, possibleLength)); 159 } 160 currentIndex = binarySearch(0, currentIndex, phonePrefix); 161 if (currentIndex < 0) { 162 return null; 163 } 164 int currentPrefix = areaCodeMapStorage.getPrefix(currentIndex); 165 if (phonePrefix == currentPrefix) { 166 return areaCodeMapStorage.getDescription(currentIndex); 167 } 168 currentSetOfLengths = currentSetOfLengths.headSet(possibleLength); 169 } 170 return null; 171 } 172 173 /** 174 * Does a binary search for {@code value} in the provided array from {@code start} to {@code end} 175 * (inclusive). Returns the position if {@code value} is found; otherwise, returns the 176 * position which has the largest value that is less than {@code value}. This means if 177 * {@code value} is the smallest, -1 will be returned. 178 */ 179 private int binarySearch(int start, int end, long value) { 180 int current = 0; 181 while (start <= end) { 182 current = (start + end) >>> 1; 183 int currentValue = areaCodeMapStorage.getPrefix(current); 184 if (currentValue == value) { 185 return current; 186 } else if (currentValue > value) { 187 current--; 188 end = current; 189 } else { 190 start = current + 1; 191 } 192 } 193 return current; 194 } 195 196 /** 197 * Dumps the mappings contained in the area code map. 198 */ 199 @Override 200 public String toString() { 201 return areaCodeMapStorage.toString(); 202 } 203 } 204
