/*
* Copyright (C) 2011 eXo Platform SAS.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.exoplatform.commons.utils;
import java.util.Locale;
/**
* Various I18N utility methods.
*
* @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a>
*/
public class I18N {
/**
* Provide a string representation of the locale argument to the {@link java.util.Locale#toString()} method.
*
* @param locale the locale
* @return the java representation
* @throws NullPointerException if the locale argument is null
*/
public static String toJavaIdentifier(Locale locale) throws NullPointerException {
if (locale == null) {
throw new NullPointerException("No null locale accepted");
}
return locale.toString();
}
private static boolean isLetter(char c) {
return c >= 'A' && c <= 'Z' || c >= 'a' && c <= 'z';
}
/**
* Parse the java string representation and returns a locale. See {@link #toJavaIdentifier(java.util.Locale)} method for
* more details.
*
* @param s the java representation to parse
* @return the corresponding locale
* @throws NullPointerException if the locale argument is null
* @throws IllegalArgumentException if the string cannot be parsed to a locale
*/
public static Locale parseJavaIdentifier(String s) throws NullPointerException, IllegalArgumentException {
if (s.length() == 0) {
throw new IllegalArgumentException("Empty locale");
}
//
char c0 = s.charAt(0);
if (c0 == '_') {
return parseCountry("", s, 0);
} else if (!isLetter(c0) || s.length() < 2 || !isLetter(s.charAt(1))) {
throw new IllegalArgumentException("Invalid Java Locale identifier: '" + s + "'");
} else {
return parseCountry(s.substring(0, 2), s, 2);
}
}
private static Locale parseCountry(String lang, String s, int index) throws IllegalArgumentException {
if (s.length() == index) {
return new Locale(lang);
} else if (s.charAt(index) != '_' || s.length() < index + 3) {
throw new IllegalArgumentException();
} else {
char c0 = s.charAt(index + 1);
if (c0 == '_') {
if (lang.length() == 0) {
throw new IllegalArgumentException();
} else {
return parseVariant(lang, "", s, index + 1);
}
} else if (!isLetter(c0) || !isLetter(s.charAt(index + 2))) {
throw new IllegalArgumentException();
} else {
return parseVariant(lang, s.substring(index + 1, index + 3), s, index + 3);
}
}
}
private static Locale parseVariant(String lang, String country, String s, int index) throws IllegalArgumentException {
if (s.length() == index) {
return new Locale(lang, country);
} else if (s.charAt(index) != '_' || s.length() < index + 2) {
throw new IllegalArgumentException();
} else {
final String variant;
if ("ja_JP_JP_#u-ca-japanese".equals(s)) {
variant = "JP";
} else if ("th_TH_TH_#u-nu-thai".equals(s)) {
variant = "TH";
} else {
for (int i = index + 1; i < s.length(); i++) {
if (!isLetter(s.charAt(i))) {
throw new IllegalArgumentException("Invalid Java Locale identifier: '" + s + "'");
}
}
variant = s.substring(index + 1);
}
return new Locale(lang, country, variant);
}
}
/**
* Provide a string representation of the locale argument according to the <a
* href="RFC 1766">http://www.ietf.org/rfc/rfc1766.txt</a>:
* <ul>
* <li>locale with a language only will return the language string</li>
* <li>otherwise it returns the language and country separated by an hyphen '-'</li>
* </ul>
*
* @param locale the locale
* @return the RFC1766 representation
* @throws NullPointerException if the locale argument is null
*/
public static String toTagIdentifier(Locale locale) throws NullPointerException {
if (locale == null) {
throw new NullPointerException("No null locale accepted");
}
String country = locale.getCountry();
String lang = locale.getLanguage();
if (country != null && country.length() > 0) {
return lang + "-" + country;
} else {
return lang;
}
}
/**
* Parse the <a href="RFC 1766">http://www.ietf.org/rfc/rfc1766.txt</a> string representation and returns a locale. See
* {@link #toTagIdentifier(java.util.Locale)} method for more details.
*
* @param s the RFC1766 representation to parse
* @return the corresponding locale
* @throws NullPointerException if the locale argument is null
* @throws IllegalArgumentException if the string cannot be parsed to a locale
*/
public static Locale parseTagIdentifier(String s) throws NullPointerException, IllegalArgumentException {
if (s == null) {
throw new NullPointerException("No null string accepted");
}
if (s.length() == 2) {
return new Locale(s.substring(0, 2));
} else if (s.length() == 5 && s.charAt(2) == '-') {
String lang = s.substring(0, 2);
String country = s.substring(3, 5);
return new Locale(lang, country);
} else {
throw new IllegalArgumentException("Locale " + s + " cannot be parsed");
}
}
/**
* Returns the parent locale of a locale or null when it does not have one.
*
* @param locale the locale
* @return the parent locale
* @throws NullPointerException if the specified locale is null
*/
public static Locale getParent(Locale locale) throws NullPointerException {
if (locale == null) {
throw new NullPointerException("No null locale accepted");
}
//
if (locale.getVariant() != null && locale.getVariant().length() > 0) {
return new Locale(locale.getLanguage(), locale.getCountry());
} else {
if (locale.getCountry() != null && locale.getCountry().length() > 0) {
return new Locale(locale.getLanguage());
} else {
return null;
}
}
}
}