362 lines
14 KiB
Java
362 lines
14 KiB
Java
/*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.apache.commons.lang3;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.Collections;
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import java.util.HashSet;
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import java.util.List;
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import java.util.Locale;
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import java.util.Set;
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import java.util.concurrent.ConcurrentHashMap;
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import java.util.concurrent.ConcurrentMap;
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/**
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* <p>Operations to assist when working with a {@link Locale}.</p>
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*
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* <p>This class tries to handle {@code null} input gracefully.
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* An exception will not be thrown for a {@code null} input.
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* Each method documents its behavior in more detail.</p>
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*
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* @since 2.2
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*/
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public class LocaleUtils {
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// class to avoid synchronization (Init on demand)
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static class SyncAvoid {
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/** Unmodifiable list of available locales. */
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private static final List<Locale> AVAILABLE_LOCALE_LIST;
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/** Unmodifiable set of available locales. */
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private static final Set<Locale> AVAILABLE_LOCALE_SET;
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static {
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final List<Locale> list = new ArrayList<>(Arrays.asList(Locale.getAvailableLocales())); // extra safe
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AVAILABLE_LOCALE_LIST = Collections.unmodifiableList(list);
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AVAILABLE_LOCALE_SET = Collections.unmodifiableSet(new HashSet<>(list));
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}
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}
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/** Concurrent map of language locales by country. */
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private static final ConcurrentMap<String, List<Locale>> cLanguagesByCountry =
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new ConcurrentHashMap<>();
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/** Concurrent map of country locales by language. */
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private static final ConcurrentMap<String, List<Locale>> cCountriesByLanguage =
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new ConcurrentHashMap<>();
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/**
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* <p>Obtains an unmodifiable list of installed locales.</p>
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*
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* <p>This method is a wrapper around {@link Locale#getAvailableLocales()}.
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* It is more efficient, as the JDK method must create a new array each
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* time it is called.</p>
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*
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* @return the unmodifiable list of available locales
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*/
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public static List<Locale> availableLocaleList() {
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return SyncAvoid.AVAILABLE_LOCALE_LIST;
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}
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/**
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* <p>Obtains an unmodifiable set of installed locales.</p>
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*
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* <p>This method is a wrapper around {@link Locale#getAvailableLocales()}.
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* It is more efficient, as the JDK method must create a new array each
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* time it is called.</p>
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*
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* @return the unmodifiable set of available locales
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*/
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public static Set<Locale> availableLocaleSet() {
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return SyncAvoid.AVAILABLE_LOCALE_SET;
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}
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/**
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* <p>Obtains the list of countries supported for a given language.</p>
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*
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* <p>This method takes a language code and searches to find the
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* countries available for that language. Variant locales are removed.</p>
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*
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* @param languageCode the 2 letter language code, null returns empty
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* @return an unmodifiable List of Locale objects, not null
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*/
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public static List<Locale> countriesByLanguage(final String languageCode) {
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if (languageCode == null) {
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return Collections.emptyList();
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}
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List<Locale> countries = cCountriesByLanguage.get(languageCode);
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if (countries == null) {
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countries = new ArrayList<>();
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final List<Locale> locales = availableLocaleList();
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for (final Locale locale : locales) {
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if (languageCode.equals(locale.getLanguage()) &&
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!locale.getCountry().isEmpty() &&
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locale.getVariant().isEmpty()) {
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countries.add(locale);
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}
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}
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countries = Collections.unmodifiableList(countries);
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cCountriesByLanguage.putIfAbsent(languageCode, countries);
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countries = cCountriesByLanguage.get(languageCode);
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}
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return countries;
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}
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/**
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* <p>Checks if the locale specified is in the list of available locales.</p>
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*
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* @param locale the Locale object to check if it is available
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* @return true if the locale is a known locale
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*/
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public static boolean isAvailableLocale(final Locale locale) {
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return availableLocaleList().contains(locale);
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}
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/**
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* Checks whether the given String is a ISO 3166 alpha-2 country code.
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*
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* @param str the String to check
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* @return true, is the given String is a ISO 3166 compliant country code.
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*/
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private static boolean isISO3166CountryCode(final String str) {
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return StringUtils.isAllUpperCase(str) && str.length() == 2;
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}
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/**
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* Checks whether the given String is a ISO 639 compliant language code.
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*
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* @param str the String to check.
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* @return true, if the given String is a ISO 639 compliant language code.
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*/
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private static boolean isISO639LanguageCode(final String str) {
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return StringUtils.isAllLowerCase(str) && (str.length() == 2 || str.length() == 3);
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}
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/**
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* Checks whether the given String is a UN M.49 numeric area code.
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*
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* @param str the String to check
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* @return true, is the given String is a UN M.49 numeric area code.
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*/
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private static boolean isNumericAreaCode(final String str) {
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return StringUtils.isNumeric(str) && str.length() == 3;
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}
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/**
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* <p>Obtains the list of languages supported for a given country.</p>
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*
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* <p>This method takes a country code and searches to find the
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* languages available for that country. Variant locales are removed.</p>
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*
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* @param countryCode the 2 letter country code, null returns empty
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* @return an unmodifiable List of Locale objects, not null
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*/
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public static List<Locale> languagesByCountry(final String countryCode) {
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if (countryCode == null) {
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return Collections.emptyList();
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}
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List<Locale> langs = cLanguagesByCountry.get(countryCode);
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if (langs == null) {
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langs = new ArrayList<>();
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final List<Locale> locales = availableLocaleList();
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for (final Locale locale : locales) {
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if (countryCode.equals(locale.getCountry()) &&
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locale.getVariant().isEmpty()) {
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langs.add(locale);
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}
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}
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langs = Collections.unmodifiableList(langs);
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cLanguagesByCountry.putIfAbsent(countryCode, langs);
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langs = cLanguagesByCountry.get(countryCode);
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}
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return langs;
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}
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/**
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* <p>Obtains the list of locales to search through when performing
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* a locale search.</p>
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*
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* <pre>
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* localeLookupList(Locale("fr", "CA", "xxx"))
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* = [Locale("fr", "CA", "xxx"), Locale("fr", "CA"), Locale("fr")]
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* </pre>
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*
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* @param locale the locale to start from
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* @return the unmodifiable list of Locale objects, 0 being locale, not null
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*/
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public static List<Locale> localeLookupList(final Locale locale) {
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return localeLookupList(locale, locale);
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}
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/**
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* <p>Obtains the list of locales to search through when performing
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* a locale search.</p>
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*
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* <pre>
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* localeLookupList(Locale("fr", "CA", "xxx"), Locale("en"))
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* = [Locale("fr", "CA", "xxx"), Locale("fr", "CA"), Locale("fr"), Locale("en"]
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* </pre>
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*
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* <p>The result list begins with the most specific locale, then the
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* next more general and so on, finishing with the default locale.
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* The list will never contain the same locale twice.</p>
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*
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* @param locale the locale to start from, null returns empty list
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* @param defaultLocale the default locale to use if no other is found
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* @return the unmodifiable list of Locale objects, 0 being locale, not null
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*/
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public static List<Locale> localeLookupList(final Locale locale, final Locale defaultLocale) {
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final List<Locale> list = new ArrayList<>(4);
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if (locale != null) {
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list.add(locale);
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if (!locale.getVariant().isEmpty()) {
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list.add(new Locale(locale.getLanguage(), locale.getCountry()));
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}
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if (!locale.getCountry().isEmpty()) {
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list.add(new Locale(locale.getLanguage(), StringUtils.EMPTY));
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}
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if (!list.contains(defaultLocale)) {
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list.add(defaultLocale);
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}
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}
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return Collections.unmodifiableList(list);
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}
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/**
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* Tries to parse a locale from the given String.
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*
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* @param str the String to parse a locale from.
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* @return a Locale instance parsed from the given String.
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* @throws IllegalArgumentException if the given String can not be parsed.
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*/
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private static Locale parseLocale(final String str) {
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if (isISO639LanguageCode(str)) {
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return new Locale(str);
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}
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final String[] segments = str.split("_", -1);
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final String language = segments[0];
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if (segments.length == 2) {
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final String country = segments[1];
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if (isISO639LanguageCode(language) && isISO3166CountryCode(country) ||
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isNumericAreaCode(country)) {
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return new Locale(language, country);
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}
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} else if (segments.length == 3) {
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final String country = segments[1];
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final String variant = segments[2];
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if (isISO639LanguageCode(language) &&
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(country.isEmpty() || isISO3166CountryCode(country) || isNumericAreaCode(country)) &&
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!variant.isEmpty()) {
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return new Locale(language, country, variant);
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}
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}
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throw new IllegalArgumentException("Invalid locale format: " + str);
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}
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/**
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* Returns the given locale if non-{@code null}, otherwise {@link Locale#getDefault()}.
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*
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* @param locale a locale or {@code null}.
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* @return the given locale if non-{@code null}, otherwise {@link Locale#getDefault()}.
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* @since 3.12.0
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*/
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public static Locale toLocale(final Locale locale) {
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return locale != null ? locale : Locale.getDefault();
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}
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/**
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* <p>Converts a String to a Locale.</p>
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*
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* <p>This method takes the string format of a locale and creates the
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* locale object from it.</p>
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*
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* <pre>
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* LocaleUtils.toLocale("") = new Locale("", "")
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* LocaleUtils.toLocale("en") = new Locale("en", "")
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* LocaleUtils.toLocale("en_GB") = new Locale("en", "GB")
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* LocaleUtils.toLocale("en_001") = new Locale("en", "001")
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* LocaleUtils.toLocale("en_GB_xxx") = new Locale("en", "GB", "xxx") (#)
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* </pre>
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*
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* <p>(#) The behavior of the JDK variant constructor changed between JDK1.3 and JDK1.4.
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* In JDK1.3, the constructor upper cases the variant, in JDK1.4, it doesn't.
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* Thus, the result from getVariant() may vary depending on your JDK.</p>
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*
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* <p>This method validates the input strictly.
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* The language code must be lowercase.
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* The country code must be uppercase.
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* The separator must be an underscore.
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* The length must be correct.
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* </p>
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*
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* @param str the locale String to convert, null returns null
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* @return a Locale, null if null input
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* @throws IllegalArgumentException if the string is an invalid format
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* @see Locale#forLanguageTag(String)
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*/
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public static Locale toLocale(final String str) {
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if (str == null) {
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return null;
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}
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if (str.isEmpty()) { // LANG-941 - JDK 8 introduced an empty locale where all fields are blank
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return new Locale(StringUtils.EMPTY, StringUtils.EMPTY);
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}
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if (str.contains("#")) { // LANG-879 - Cannot handle Java 7 script & extensions
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throw new IllegalArgumentException("Invalid locale format: " + str);
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}
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final int len = str.length();
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if (len < 2) {
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throw new IllegalArgumentException("Invalid locale format: " + str);
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}
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final char ch0 = str.charAt(0);
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if (ch0 == '_') {
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if (len < 3) {
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throw new IllegalArgumentException("Invalid locale format: " + str);
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}
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final char ch1 = str.charAt(1);
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final char ch2 = str.charAt(2);
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if (!Character.isUpperCase(ch1) || !Character.isUpperCase(ch2)) {
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throw new IllegalArgumentException("Invalid locale format: " + str);
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}
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if (len == 3) {
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return new Locale(StringUtils.EMPTY, str.substring(1, 3));
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}
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if (len < 5) {
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throw new IllegalArgumentException("Invalid locale format: " + str);
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}
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if (str.charAt(3) != '_') {
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throw new IllegalArgumentException("Invalid locale format: " + str);
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}
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return new Locale(StringUtils.EMPTY, str.substring(1, 3), str.substring(4));
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}
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return parseLocale(str);
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}
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/**
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* <p>{@code LocaleUtils} instances should NOT be constructed in standard programming.
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* Instead, the class should be used as {@code LocaleUtils.toLocale("en_GB");}.</p>
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*
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* <p>This constructor is public to permit tools that require a JavaBean instance
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* to operate.</p>
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*/
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public LocaleUtils() {
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}
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}
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