/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.commons.lang3;
import java.util.
ArrayList;
import java.util.
Arrays;
import java.util.
Collections;
import java.util.
HashSet;
import java.util.
List;
import java.util.
Locale;
import java.util.
Set;
import java.util.concurrent.
ConcurrentHashMap;
import java.util.concurrent.
ConcurrentMap;
/**
* <p>Operations to assist when working with a {@link Locale}.</p>
*
* <p>This class tries to handle {@code null} input gracefully.
* An exception will not be thrown for a {@code null} input.
* Each method documents its behaviour in more detail.</p>
*
* @since 2.2
*/
public class
LocaleUtils {
/** Concurrent map of language locales by country. */
private static final
ConcurrentMap<
String,
List<
Locale>>
cLanguagesByCountry =
new
ConcurrentHashMap<
String,
List<
Locale>>();
/** Concurrent map of country locales by language. */
private static final
ConcurrentMap<
String,
List<
Locale>>
cCountriesByLanguage =
new
ConcurrentHashMap<
String,
List<
Locale>>();
/**
* <p>{@code LocaleUtils} instances should NOT be constructed in standard programming.
* Instead, the class should be used as {@code LocaleUtils.toLocale("en_GB");}.</p>
*
* <p>This constructor is public to permit tools that require a JavaBean instance
* to operate.</p>
*/
public
LocaleUtils() {
super();
}
//-----------------------------------------------------------------------
/**
* <p>Converts a String to a Locale.</p>
*
* <p>This method takes the string format of a locale and creates the
* locale object from it.</p>
*
* <pre>
* LocaleUtils.toLocale("") = new Locale("", "")
* LocaleUtils.toLocale("en") = new Locale("en", "")
* LocaleUtils.toLocale("en_GB") = new Locale("en", "GB")
* LocaleUtils.toLocale("en_GB_xxx") = new Locale("en", "GB", "xxx") (#)
* </pre>
*
* <p>(#) The behaviour of the JDK variant constructor changed between JDK1.3 and JDK1.4.
* In JDK1.3, the constructor upper cases the variant, in JDK1.4, it doesn't.
* Thus, the result from getVariant() may vary depending on your JDK.</p>
*
* <p>This method validates the input strictly.
* The language code must be lowercase.
* The country code must be uppercase.
* The separator must be an underscore.
* The length must be correct.
* </p>
*
* @param str the locale String to convert, null returns null
* @return a Locale, null if null input
* @throws IllegalArgumentException if the string is an invalid format
* @see Locale#forLanguageTag(String)
*/
public static
Locale toLocale(final
String str) {
if (
str == null) {
return null;
}
if (
str.
isEmpty()) { // LANG-941 - JDK 8 introduced an empty locale where all fields are blank
return new
Locale(
StringUtils.
EMPTY,
StringUtils.
EMPTY);
}
if (
str.
contains("#")) { // LANG-879 - Cannot handle Java 7 script & extensions
throw new
IllegalArgumentException("Invalid locale format: " +
str);
}
final int
len =
str.
length();
if (
len < 2) {
throw new
IllegalArgumentException("Invalid locale format: " +
str);
}
final char
ch0 =
str.
charAt(0);
if (
ch0 == '_') {
if (
len < 3) {
throw new
IllegalArgumentException("Invalid locale format: " +
str);
}
final char
ch1 =
str.
charAt(1);
final char
ch2 =
str.
charAt(2);
if (!
Character.
isUpperCase(
ch1) || !
Character.
isUpperCase(
ch2)) {
throw new
IllegalArgumentException("Invalid locale format: " +
str);
}
if (
len == 3) {
return new
Locale(
StringUtils.
EMPTY,
str.
substring(1, 3));
}
if (
len < 5) {
throw new
IllegalArgumentException("Invalid locale format: " +
str);
}
if (
str.
charAt(3) != '_') {
throw new
IllegalArgumentException("Invalid locale format: " +
str);
}
return new
Locale(
StringUtils.
EMPTY,
str.
substring(1, 3),
str.
substring(4));
}
final
String[]
split =
str.
split("_", -1);
final int
occurrences =
split.length -1;
switch (
occurrences) {
case 0:
if (
StringUtils.
isAllLowerCase(
str) && (
len == 2 ||
len == 3)) {
return new
Locale(
str);
}
throw new
IllegalArgumentException("Invalid locale format: " +
str);
case 1:
if (
StringUtils.
isAllLowerCase(
split[0]) &&
(
split[0].
length() == 2 ||
split[0].
length() == 3) &&
split[1].
length() == 2 &&
StringUtils.
isAllUpperCase(
split[1])) {
return new
Locale(
split[0],
split[1]);
}
throw new
IllegalArgumentException("Invalid locale format: " +
str);
case 2:
if (
StringUtils.
isAllLowerCase(
split[0]) &&
(
split[0].
length() == 2 ||
split[0].
length() == 3) &&
(
split[1].
length() == 0 ||
split[1].
length() == 2 &&
StringUtils.
isAllUpperCase(
split[1])) &&
split[2].
length() > 0) {
return new
Locale(
split[0],
split[1],
split[2]);
}
//$FALL-THROUGH$
default:
throw new
IllegalArgumentException("Invalid locale format: " +
str);
}
}
//-----------------------------------------------------------------------
/**
* <p>Obtains the list of locales to search through when performing
* a locale search.</p>
*
* <pre>
* localeLookupList(Locale("fr","CA","xxx"))
* = [Locale("fr","CA","xxx"), Locale("fr","CA"), Locale("fr")]
* </pre>
*
* @param locale the locale to start from
* @return the unmodifiable list of Locale objects, 0 being locale, not null
*/
public static
List<
Locale>
localeLookupList(final
Locale locale) {
return
localeLookupList(
locale,
locale);
}
//-----------------------------------------------------------------------
/**
* <p>Obtains the list of locales to search through when performing
* a locale search.</p>
*
* <pre>
* localeLookupList(Locale("fr", "CA", "xxx"), Locale("en"))
* = [Locale("fr","CA","xxx"), Locale("fr","CA"), Locale("fr"), Locale("en"]
* </pre>
*
* <p>The result list begins with the most specific locale, then the
* next more general and so on, finishing with the default locale.
* The list will never contain the same locale twice.</p>
*
* @param locale the locale to start from, null returns empty list
* @param defaultLocale the default locale to use if no other is found
* @return the unmodifiable list of Locale objects, 0 being locale, not null
*/
public static
List<
Locale>
localeLookupList(final
Locale locale, final
Locale defaultLocale) {
final
List<
Locale>
list = new
ArrayList<
Locale>(4);
if (
locale != null) {
list.
add(
locale);
if (
locale.
getVariant().
length() > 0) {
list.
add(new
Locale(
locale.
getLanguage(),
locale.
getCountry()));
}
if (
locale.
getCountry().
length() > 0) {
list.
add(new
Locale(
locale.
getLanguage(),
StringUtils.
EMPTY));
}
if (
list.
contains(
defaultLocale) == false) {
list.
add(
defaultLocale);
}
}
return
Collections.
unmodifiableList(
list);
}
//-----------------------------------------------------------------------
/**
* <p>Obtains an unmodifiable list of installed locales.</p>
*
* <p>This method is a wrapper around {@link Locale#getAvailableLocales()}.
* It is more efficient, as the JDK method must create a new array each
* time it is called.</p>
*
* @return the unmodifiable list of available locales
*/
public static
List<
Locale>
availableLocaleList() {
return
SyncAvoid.
AVAILABLE_LOCALE_LIST;
}
//-----------------------------------------------------------------------
/**
* <p>Obtains an unmodifiable set of installed locales.</p>
*
* <p>This method is a wrapper around {@link Locale#getAvailableLocales()}.
* It is more efficient, as the JDK method must create a new array each
* time it is called.</p>
*
* @return the unmodifiable set of available locales
*/
public static
Set<
Locale>
availableLocaleSet() {
return
SyncAvoid.
AVAILABLE_LOCALE_SET;
}
//-----------------------------------------------------------------------
/**
* <p>Checks if the locale specified is in the list of available locales.</p>
*
* @param locale the Locale object to check if it is available
* @return true if the locale is a known locale
*/
public static boolean
isAvailableLocale(final
Locale locale) {
return
availableLocaleList().
contains(
locale);
}
//-----------------------------------------------------------------------
/**
* <p>Obtains the list of languages supported for a given country.</p>
*
* <p>This method takes a country code and searches to find the
* languages available for that country. Variant locales are removed.</p>
*
* @param countryCode the 2 letter country code, null returns empty
* @return an unmodifiable List of Locale objects, not null
*/
public static
List<
Locale>
languagesByCountry(final
String countryCode) {
if (
countryCode == null) {
return
Collections.
emptyList();
}
List<
Locale>
langs =
cLanguagesByCountry.
get(
countryCode);
if (
langs == null) {
langs = new
ArrayList<
Locale>();
final
List<
Locale>
locales =
availableLocaleList();
for (int
i = 0;
i <
locales.
size();
i++) {
final
Locale locale =
locales.
get(
i);
if (
countryCode.
equals(
locale.
getCountry()) &&
locale.
getVariant().
isEmpty()) {
langs.
add(
locale);
}
}
langs =
Collections.
unmodifiableList(
langs);
cLanguagesByCountry.
putIfAbsent(
countryCode,
langs);
langs =
cLanguagesByCountry.
get(
countryCode);
}
return
langs;
}
//-----------------------------------------------------------------------
/**
* <p>Obtains the list of countries supported for a given language.</p>
*
* <p>This method takes a language code and searches to find the
* countries available for that language. Variant locales are removed.</p>
*
* @param languageCode the 2 letter language code, null returns empty
* @return an unmodifiable List of Locale objects, not null
*/
public static
List<
Locale>
countriesByLanguage(final
String languageCode) {
if (
languageCode == null) {
return
Collections.
emptyList();
}
List<
Locale>
countries =
cCountriesByLanguage.
get(
languageCode);
if (
countries == null) {
countries = new
ArrayList<
Locale>();
final
List<
Locale>
locales =
availableLocaleList();
for (int
i = 0;
i <
locales.
size();
i++) {
final
Locale locale =
locales.
get(
i);
if (
languageCode.
equals(
locale.
getLanguage()) &&
locale.
getCountry().
length() != 0 &&
locale.
getVariant().
isEmpty()) {
countries.
add(
locale);
}
}
countries =
Collections.
unmodifiableList(
countries);
cCountriesByLanguage.
putIfAbsent(
languageCode,
countries);
countries =
cCountriesByLanguage.
get(
languageCode);
}
return
countries;
}
//-----------------------------------------------------------------------
// class to avoid synchronization (Init on demand)
static class
SyncAvoid {
/** Unmodifiable list of available locales. */
private static final
List<
Locale>
AVAILABLE_LOCALE_LIST;
/** Unmodifiable set of available locales. */
private static final
Set<
Locale>
AVAILABLE_LOCALE_SET;
static {
final
List<
Locale>
list = new
ArrayList<
Locale>(
Arrays.
asList(
Locale.
getAvailableLocales())); // extra safe
AVAILABLE_LOCALE_LIST =
Collections.
unmodifiableList(
list);
AVAILABLE_LOCALE_SET =
Collections.
unmodifiableSet(new
HashSet<
Locale>(
list));
}
}
}