Converts a String to a Locale
// Copyright 2008 The Apache Software Foundation
//
// 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.
import java.util.Locale;
/**
* Contains code borrowed from <a href="http://commons.apache.org/lang/">commons-lang</a>.
*/
public class LocaleUtils
{
/**
* <p>Converts a String to a Locale.</p> <p/> <p>This method takes the string format of a locale and creates the
* locale object from it.</p> <p/>
* <pre>
* 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/> <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/> <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 input the locale String to convert, null returns null
* @return a Locale, null if null input
* @throws IllegalArgumentException if the string is an invalid format
*/
public static Locale toLocale(String input)
{
if (input == null)
return null;
int len = input.length();
if (len != 2 && len != 5 && len < 7)
fail(input);
char ch0 = input.charAt(0);
char ch1 = input.charAt(1);
if (ch0 < 'a' || ch0 > 'z' || ch1 < 'a' || ch1 > 'z')
fail(input);
if (len == 2)
return new Locale(input, "");
if (input.charAt(2) != '_')
fail(input);
char ch3 = input.charAt(3);
if (ch3 == '_')
return new Locale(input.substring(0, 2), "", input.substring(4));
char ch4 = input.charAt(4);
if (ch3 < 'A' || ch3 > 'Z' || ch4 < 'A' || ch4 > 'Z')
fail(input);
if (len == 5)
return new Locale(input.substring(0, 2), input.substring(3, 5));
if (input.charAt(5) != '_')
fail(input);
return new Locale(input.substring(0, 2), input.substring(3, 5), input.substring(6));
}
private static void fail(String input)
{
throw new IllegalArgumentException(String.format("Unable to convert '%s' to a Locale instance.", input));
}
}
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