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'databene commons' is an open source Java library by Volker Bergmann.
It provides extensions to the Java core library by utility classes, abstract concepts
and concrete implementations.
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/*
* Copyright (C) 2004-2015 Volker Bergmann ([email protected]).
* All rights reserved.
*
* 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 org.databene.commons;
import java.text.DecimalFormat;
import java.util.*;
import java.util.concurrent.Callable;
import java.io.IOException;
/**
* Provides locale operations like determining the parent of a locale,
* finding a locale by code, providing the characters of a locale
* and a so-called 'fallback locale'.
* Created: 26.09.2006 23:34:41
* @author Volker Bergmann
*/
public final class LocaleUtil {
/** The locale to use by default */
private static final Locale FALLBACK_LOCALE = Locale.US;
/** collects the special letters of locales as set of Characters, indexed by the locale. */
private static Map> specialLetters;
/** Static initializer calls readConfigFile(). @see #readConfigFile() */
static {
readConfigFile();
}
// interface -------------------------------------------------------------------------------------------------------
/**
* Returns a set that contains all letters of the specified locale.
* @param locale the locale of which the character set is requested
* @return a set of characters that contains all letters of the specified locale
* @exception UnsupportedOperationException if the locale is not supported
*/
public static Set letters(Locale locale) {
Set set = nullTolerantLetters(locale);
if (set == null)
throw new UnsupportedOperationException("Locale not supported: " + locale);
return set;
}
/**
* Determines a locale's parent, e.g. for a locale 'de_DE' it returns 'de'.
* @param locale the locale of which to determine the parent
* @return the locale's parent, or null if the locale has no parent.
*/
public static Locale parent(Locale locale) {
String variant = locale.getVariant();
if (!StringUtil.isEmpty(variant)){
if (variant.contains("_")) {
String[] variantPath = StringUtil.tokenize(variant, '_');
variant = ArrayFormat.formatPart("_", 0, variantPath.length - 1, variantPath);
return new Locale(locale.getLanguage(), locale.getCountry(), variant);
} else
return new Locale(locale.getLanguage(), locale.getCountry());
} else if (!StringUtil.isEmpty(locale.getCountry()))
return new Locale(locale.getLanguage());
else
return null;
}
/**
* Returns the fallback locale.
* This differs from the default locale for cases in which it is desirable to
* restrict the used character ranges to an unproblematic minimum.
* @return the fallback locale.
*/
public static Locale getFallbackLocale() {
return FALLBACK_LOCALE;
}
/**
* Maps the locale code to a locale, e.g. de_DE to Locale.GERMANY.
* @param code the locale colde to map
* @return a locale instance the represents the code
*/
public static Locale getLocale(String code) {
if (StringUtil.isEmpty(code))
throw new IllegalArgumentException("code is empty");
String[] path = StringUtil.tokenize(code, '_');
switch (path.length) {
case 1 : return new Locale(path[0]);
case 2 : return new Locale(path[0], path[1]);
case 3 : return new Locale(path[0], path[1], path[2]);
default : return new Locale(path[0], path[1], ArrayFormat.formatPart("_", 2, path.length - 2, path));
}
}
public static String availableLocaleUrl(String baseName, Locale locale, String suffix) {
String localeString = locale.toString();
do {
String url = baseName;
if (!StringUtil.isEmpty(localeString))
url += "_" + localeString;
url += suffix;
if (IOUtil.isURIAvailable(url))
return url;
localeString = reduceLocaleString(localeString);
} while (localeString != null);
return null;
}
private static String reduceLocaleString(String localeString) {
if (localeString == null || localeString.length() == 0)
return null;
int separatorIndex = localeString.lastIndexOf('_');
if (separatorIndex < 0)
return "";
return localeString.substring(0, separatorIndex);
}
public static String getDefaultCountryCode() {
String result = Locale.getDefault().getCountry();
if (StringUtil.isEmpty(result))
result = getFallbackLocale().getCountry();
return result;
}
public static Locale language(Locale locale) {
Locale result = locale;
Locale parent;
while ((parent = parent(result)) != null)
result = parent;
return result;
}
// private helpers -------------------------------------------------------------------------------------------------
/**
* @param locale the locale of which to get the letters.
* @return the letters of a locale, null if the locale is unknown.
*/
private static Set nullTolerantLetters(Locale locale) {
if (locale == null)
return null;
Set set = specialLetters.get(locale);
if (set != null)
return set;
Locale parent = locale;
while ((parent = parent(parent)) != null) {
set = specialLetters.get(parent);
if (set != null)
return set;
}
return latinSet();
}
/**
* Reads the config file org/databene/commons/special-letters.properties from the file system or the path
* and initializes the internal specialLetters map.
*/
private static void readConfigFile() {
try {
specialLetters = new HashMap>();
Map properties = IOUtil.readProperties(
"org/databene/commons/special-letters.properties", Encodings.UTF_8);
for (Map.Entry entry : properties.entrySet()) {
Locale locale = getLocale(String.valueOf(entry.getKey()));
String specialChars = String.valueOf(entry.getValue());
Set charSet = latinSet();
for (int i = 0; i < specialChars.length(); i++)
charSet.add(specialChars.charAt(i));
specialLetters.put(locale, charSet);
}
} catch (IOException e) {
throw new ConfigurationError("Setup file for locale-specific letters is missing", e);
}
}
private static Set latinSet() {
return new CharSet('A', 'Z').addRange('a', 'z').getSet();
}
public static void runInLocale(Locale locale, Runnable task) {
Locale realLocale = Locale.getDefault();
try {
Locale.setDefault(locale);
task.run();
} finally {
Locale.setDefault(realLocale);
}
}
public static T callInLocale(Locale locale, Callable task) throws Exception {
Locale realLocale = Locale.getDefault();
try {
Locale.setDefault(locale);
return task.call();
} finally {
Locale.setDefault(realLocale);
}
}
public static char getDecimalSeparator() {
return new DecimalFormat().getDecimalFormatSymbols().getDecimalSeparator();
}
}