/*
* Copyright (C) 2011 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.i18n.phonenumbers.geocoding;
import com.android.i18n.phonenumbers.PhoneNumberUtil;
import com.android.i18n.phonenumbers.Phonenumber.PhoneNumber;
import java.io.ByteArrayOutputStream;
import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.io.ObjectOutputStream;
import java.util.SortedMap;
import java.util.SortedSet;
import java.util.logging.Logger;
/**
* A utility that maps phone number prefixes to a string describing the geographical area the prefix
* covers.
*
* @author Shaopeng Jia
*/
public class AreaCodeMap implements Externalizable {
private final PhoneNumberUtil phoneUtil = PhoneNumberUtil.getInstance();
private static final Logger LOGGER = Logger.getLogger(AreaCodeMap.class.getName());
private AreaCodeMapStorageStrategy areaCodeMapStorage;
// @VisibleForTesting
AreaCodeMapStorageStrategy getAreaCodeMapStorage() {
return areaCodeMapStorage;
}
/**
* Creates an empty {@link AreaCodeMap}. The default constructor is necessary for implementing
* {@link Externalizable}. The empty map could later be populated by
* {@link #readAreaCodeMap(java.util.SortedMap)} or {@link #readExternal(java.io.ObjectInput)}.
*/
public AreaCodeMap() {}
/**
* Gets the size of the provided area code map storage. The map storage passed-in will be filled
* as a result.
*/
private static int getSizeOfAreaCodeMapStorage(AreaCodeMapStorageStrategy mapStorage,
SortedMap<Integer, String> areaCodeMap) throws IOException {
mapStorage.readFromSortedMap(areaCodeMap);
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
ObjectOutputStream objectOutputStream = new ObjectOutputStream(byteArrayOutputStream);
mapStorage.writeExternal(objectOutputStream);
objectOutputStream.flush();
int sizeOfStorage = byteArrayOutputStream.size();
objectOutputStream.close();
return sizeOfStorage;
}
private AreaCodeMapStorageStrategy createDefaultMapStorage() {
return new DefaultMapStorage();
}
private AreaCodeMapStorageStrategy createFlyweightMapStorage() {
return new FlyweightMapStorage();
}
/**
* Gets the smaller area code map storage strategy according to the provided area code map. It
* actually uses (outputs the data to a stream) both strategies and retains the best one which
* make this method quite expensive.
*/
// @VisibleForTesting
AreaCodeMapStorageStrategy getSmallerMapStorage(SortedMap<Integer, String> areaCodeMap) {
try {
AreaCodeMapStorageStrategy flyweightMapStorage = createFlyweightMapStorage();
int sizeOfFlyweightMapStorage = getSizeOfAreaCodeMapStorage(flyweightMapStorage, areaCodeMap);
AreaCodeMapStorageStrategy defaultMapStorage = createDefaultMapStorage();
int sizeOfDefaultMapStorage = getSizeOfAreaCodeMapStorage(defaultMapStorage, areaCodeMap);
return sizeOfFlyweightMapStorage < sizeOfDefaultMapStorage
? flyweightMapStorage : defaultMapStorage;
} catch (IOException e) {
LOGGER.severe(e.getMessage());
return createFlyweightMapStorage();
}
}
/**
* Creates an {@link AreaCodeMap} initialized with {@code sortedAreaCodeMap}. Note that the
* underlying implementation of this method is expensive thus should not be called by
* time-critical applications.
*
* @param sortedAreaCodeMap a map from phone number prefixes to descriptions of corresponding
* geographical areas, sorted in ascending order of the phone number prefixes as integers.
*/
public void readAreaCodeMap(SortedMap<Integer, String> sortedAreaCodeMap) {
areaCodeMapStorage = getSmallerMapStorage(sortedAreaCodeMap);
}
/**
* Supports Java Serialization.
*/
public void readExternal(ObjectInput objectInput) throws IOException {
// Read the area code map storage strategy flag.
boolean useFlyweightMapStorage = objectInput.readBoolean();
if (useFlyweightMapStorage) {
areaCodeMapStorage = new FlyweightMapStorage();
} else {
areaCodeMapStorage = new DefaultMapStorage();
}
areaCodeMapStorage.readExternal(objectInput);
}
/**
* Supports Java Serialization.
*/
public void writeExternal(ObjectOutput objectOutput) throws IOException {
objectOutput.writeBoolean(areaCodeMapStorage.isFlyweight());
areaCodeMapStorage.writeExternal(objectOutput);
}
/**
* Returns the description of the geographical area the {@code number} corresponds to.
*
* @param number the phone number to look up
* @return the description of the geographical area
*/
String lookup(PhoneNumber number) {
int numOfEntries = areaCodeMapStorage.getNumOfEntries();
if (numOfEntries == 0) {
return "";
}
long phonePrefix =
Long.parseLong(number.getCountryCode() + phoneUtil.getNationalSignificantNumber(number));
int currentIndex = numOfEntries - 1;
SortedSet<Integer> currentSetOfLengths = areaCodeMapStorage.getPossibleLengths();
while (currentSetOfLengths.size() > 0) {
Integer possibleLength = currentSetOfLengths.last();
String phonePrefixStr = String.valueOf(phonePrefix);
if (phonePrefixStr.length() > possibleLength) {
phonePrefix = Long.parseLong(phonePrefixStr.substring(0, possibleLength));
}
currentIndex = binarySearch(0, currentIndex, phonePrefix);
if (currentIndex < 0) {
return "";
}
int currentPrefix = areaCodeMapStorage.getPrefix(currentIndex);
if (phonePrefix == currentPrefix) {
return areaCodeMapStorage.getDescription(currentIndex);
}
currentSetOfLengths = currentSetOfLengths.headSet(possibleLength);
}
return "";
}
/**
* Does a binary search for {@code value} in the provided array from {@code start} to {@code end}
* (inclusive). Returns the position if {@code value} is found; otherwise, returns the
* position which has the largest value that is less than {@code value}. This means if
* {@code value} is the smallest, -1 will be returned.
*/
private int binarySearch(int start, int end, long value) {
int current = 0;
while (start <= end) {
current = (start + end) >>> 1;
int currentValue = areaCodeMapStorage.getPrefix(current);
if (currentValue == value) {
return current;
} else if (currentValue > value) {
current--;
end = current;
} else {
start = current + 1;
}
}
return current;
}
/**
* Dumps the mappings contained in the area code map.
*/
@Override
public String toString() {
return areaCodeMapStorage.toString();
}
}