/*

  * Copyright (c) 1996, 2011, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.  Oracle designates this

  * particular file as subject to the "Classpath" exception as provided

  * by Oracle in the LICENSE file that accompanied this code.

  *

  * This code 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 General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

  */

 /*

  * (C) Copyright Taligent, Inc. 1996, 1997 - All Rights Reserved

  * (C) Copyright IBM Corp. 1996 - 1998 - All Rights Reserved

  *

  * The original version of this source code and documentation

  * is copyrighted and owned by Taligent, Inc., a wholly-owned

  * subsidiary of IBM. These materials are provided under terms

  * of a License Agreement between Taligent and Sun. This technology

  * is protected by multiple US and International patents.

  *

  * This notice and attribution to Taligent may not be removed.

  * Taligent is a registered trademark of Taligent, Inc.

  *

  */

 package java.util;

 import java.io.IOException;

 import java.io.ObjectInputStream;

 import java.io.ObjectOutputStream;

 import java.io.ObjectStreamField;

 import java.io.Serializable;

 import java.security.AccessController;

 import java.text.MessageFormat;

 import java.util.spi.LocaleNameProvider;

 import sun.security.action.GetPropertyAction;

 import sun.util.LocaleServiceProviderPool;

 import sun.util.locale.BaseLocale;

 import sun.util.locale.InternalLocaleBuilder;

 import sun.util.locale.LanguageTag;

 import sun.util.locale.LocaleExtensions;

 import sun.util.locale.LocaleObjectCache;

 import sun.util.locale.LocaleSyntaxException;

 import sun.util.locale.LocaleUtils;

 import sun.util.locale.ParseStatus;

 import sun.util.locale.UnicodeLocaleExtension;

 import sun.util.resources.LocaleData;

 import sun.util.resources.OpenListResourceBundle;

 /**

  * A <code>Locale</code> object represents a specific geographical, political,

  * or cultural region. An operation that requires a <code>Locale</code> to perform

  * its task is called <em>locale-sensitive</em> and uses the <code>Locale</code>

  * to tailor information for the user. For example, displaying a number

  * is a locale-sensitive operation— the number should be formatted

  * according to the customs and conventions of the user's native country,

  * region, or culture.

  *

  * <p> The <code>Locale</code> class implements identifiers

  * interchangeable with BCP 47 (IETF BCP 47, "Tags for Identifying

  * Languages"), with support for the LDML (UTS#35, "Unicode Locale

  * Data Markup Language") BCP 47-compatible extensions for locale data

  * exchange.

  *

  * <p> A <code>Locale</code> object logically consists of the fields

  * described below.

  *

  * <dl>

  *   <dt><a name="def_language"/><b>language</b></dt>

  *

  *   <dd>ISO 639 alpha-2 or alpha-3 language code, or registered

  *   language subtags up to 8 alpha letters (for future enhancements).

  *   When a language has both an alpha-2 code and an alpha-3 code, the

  *   alpha-2 code must be used.  You can find a full list of valid

  *   language codes in the IANA Language Subtag Registry (search for

  *   "Type: language").  The language field is case insensitive, but

  *   <code>Locale</code> always canonicalizes to lower case.</dd><br>

  *

  *   <dd>Well-formed language values have the form

  *   <code>[a-zA-Z]{2,8}</code>.  Note that this is not the the full

  *   BCP47 language production, since it excludes extlang.  They are

  *   not needed since modern three-letter language codes replace

  *   them.</dd><br>

  *

  *   <dd>Example: "en" (English), "ja" (Japanese), "kok" (Konkani)</dd><br>

  *

  *   <dt><a name="def_script"/><b>script</b></dt>

  *

  *   <dd>ISO 15924 alpha-4 script code.  You can find a full list of

  *   valid script codes in the IANA Language Subtag Registry (search

  *   for "Type: script").  The script field is case insensitive, but

  *   <code>Locale</code> always canonicalizes to title case (the first

  *   letter is upper case and the rest of the letters are lower

  *   case).</dd><br>

  *

  *   <dd>Well-formed script values have the form

  *   <code>[a-zA-Z]{4}</code></dd><br>

  *

  *   <dd>Example: "Latn" (Latin), "Cyrl" (Cyrillic)</dd><br>

  *

  *   <dt><a name="def_region"/><b>country (region)</b></dt>

  *

  *   <dd>ISO 3166 alpha-2 country code or UN M.49 numeric-3 area code.

  *   You can find a full list of valid country and region codes in the

  *   IANA Language Subtag Registry (search for "Type: region").  The

  *   country (region) field is case insensitive, but

  *   <code>Locale</code> always canonicalizes to upper case.</dd><br>

  *

  *   <dd>Well-formed country/region values have

  *   the form <code>[a-zA-Z]{2} | [0-9]{3}</code></dd><br>

  *

  *   <dd>Example: "US" (United States), "FR" (France), "029"

  *   (Caribbean)</dd><br>

  *

  *   <dt><a name="def_variant"/><b>variant</b></dt>

  *

  *   <dd>Any arbitrary value used to indicate a variation of a

  *   <code>Locale</code>.  Where there are two or more variant values

  *   each indicating its own semantics, these values should be ordered

  *   by importance, with most important first, separated by

  *   underscore('_').  The variant field is case sensitive.</dd><br>

  *

  *   <dd>Note: IETF BCP 47 places syntactic restrictions on variant

  *   subtags.  Also BCP 47 subtags are strictly used to indicate

  *   additional variations that define a language or its dialects that

  *   are not covered by any combinations of language, script and

  *   region subtags.  You can find a full list of valid variant codes

  *   in the IANA Language Subtag Registry (search for "Type: variant").

  *

  *   <p>However, the variant field in <code>Locale</code> has

  *   historically been used for any kind of variation, not just

  *   language variations.  For example, some supported variants

  *   available in Java SE Runtime Environments indicate alternative

  *   cultural behaviors such as calendar type or number script.  In

  *   BCP 47 this kind of information, which does not identify the

  *   language, is supported by extension subtags or private use

  *   subtags.</dd><br>

  *

  *   <dd>Well-formed variant values have the form <code>SUBTAG

  *   (('_'|'-') SUBTAG)*</code> where <code>SUBTAG =

  *   [0-9][0-9a-zA-Z]{3} | [0-9a-zA-Z]{5,8}</code>. (Note: BCP 47 only

  *   uses hyphen ('-') as a delimiter, this is more lenient).</dd><br>

  *

  *   <dd>Example: "polyton" (Polytonic Greek), "POSIX"</dd><br>

  *

  *   <dt><a name="def_extensions"/><b>extensions</b></dt>

  *

  *   <dd>A map from single character keys to string values, indicating

  *   extensions apart from language identification.  The extensions in

  *   <code>Locale</code> implement the semantics and syntax of BCP 47

  *   extension subtags and private use subtags. The extensions are

  *   case insensitive, but <code>Locale</code> canonicalizes all

  *   extension keys and values to lower case. Note that extensions

  *   cannot have empty values.</dd><br>

  *

  *   <dd>Well-formed keys are single characters from the set

  *   <code>[0-9a-zA-Z]</code>.  Well-formed values have the form

  *   <code>SUBTAG ('-' SUBTAG)*</code> where for the key 'x'

  *   <code>SUBTAG = [0-9a-zA-Z]{1,8}</code> and for other keys

  *   <code>SUBTAG = [0-9a-zA-Z]{2,8}</code> (that is, 'x' allows

  *   single-character subtags).</dd><br>

  *

  *   <dd>Example: key="u"/value="ca-japanese" (Japanese Calendar),

  *   key="x"/value="java-1-7"</dd>

  * </dl>

  *

  * <b>Note:</b> Although BCP 47 requires field values to be registered

  * in the IANA Language Subtag Registry, the <code>Locale</code> class

  * does not provide any validation features.  The <code>Builder</code>

  * only checks if an individual field satisfies the syntactic

  * requirement (is well-formed), but does not validate the value

  * itself.  See {@link Builder} for details.

  *

  * <h4><a name="def_locale_extension">Unicode locale/language extension</h4>

  *

  * <p>UTS#35, "Unicode Locale Data Markup Language" defines optional

  * attributes and keywords to override or refine the default behavior

  * associated with a locale.  A keyword is represented by a pair of

  * key and type.  For example, "nu-thai" indicates that Thai local

  * digits (value:"thai") should be used for formatting numbers

  * (key:"nu").

  *

  * <p>The keywords are mapped to a BCP 47 extension value using the

  * extension key 'u' ({@link #UNICODE_LOCALE_EXTENSION}).  The above

  * example, "nu-thai", becomes the extension "u-nu-thai".code

  *

  * <p>Thus, when a <code>Locale</code> object contains Unicode locale

  * attributes and keywords,

  * <code>getExtension(UNICODE_LOCALE_EXTENSION)</code> will return a

  * String representing this information, for example, "nu-thai".  The

  * <code>Locale</code> class also provides {@link

  * #getUnicodeLocaleAttributes}, {@link #getUnicodeLocaleKeys}, and

  * {@link #getUnicodeLocaleType} which allow you to access Unicode

  * locale attributes and key/type pairs directly.  When represented as

  * a string, the Unicode Locale Extension lists attributes

  * alphabetically, followed by key/type sequences with keys listed

  * alphabetically (the order of subtags comprising a key's type is

  * fixed when the type is defined)

  *

  * <p>A well-formed locale key has the form

  * <code>[0-9a-zA-Z]{2}</code>.  A well-formed locale type has the

  * form <code>"" | [0-9a-zA-Z]{3,8} ('-' [0-9a-zA-Z]{3,8})*</code> (it

  * can be empty, or a series of subtags 3-8 alphanums in length).  A

  * well-formed locale attribute has the form

  * <code>[0-9a-zA-Z]{3,8}</code> (it is a single subtag with the same

  * form as a locale type subtag).

  *

  * <p>The Unicode locale extension specifies optional behavior in

  * locale-sensitive services.  Although the LDML specification defines

  * various keys and values, actual locale-sensitive service

  * implementations in a Java Runtime Environment might not support any

  * particular Unicode locale attributes or key/type pairs.

  *

  * <h4>Creating a Locale</h4>

  *

  * <p>There are several different ways to create a <code>Locale</code>

  * object.

  *

  * <h5>Builder</h5>

  *

  * <p>Using {@link Builder} you can construct a <code>Locale</code> object

  * that conforms to BCP 47 syntax.

  *

  * <h5>Constructors</h5>

  *

  * <p>The <code>Locale</code> class provides three constructors:

  * <blockquote>

  * <pre>

  *     {@link #Locale(String language)}

  *     {@link #Locale(String language, String country)}

  *     {@link #Locale(String language, String country, String variant)}

  * </pre>

  * </blockquote>

  * These constructors allow you to create a <code>Locale</code> object

  * with language, country and variant, but you cannot specify

  * script or extensions.

  *

  * <h5>Factory Methods</h5>

  *

  * <p>The method {@link #forLanguageTag} creates a <code>Locale</code>

  * object for a well-formed BCP 47 language tag.

  *

  * <h5>Locale Constants</h5>

  *

  * <p>The <code>Locale</code> class provides a number of convenient constants

  * that you can use to create <code>Locale</code> objects for commonly used

  * locales. For example, the following creates a <code>Locale</code> object

  * for the United States:

  * <blockquote>

  * <pre>

  *     Locale.US

  * </pre>

  * </blockquote>

  *

  * <h4>Use of Locale</h4>

  *

  * <p>Once you've created a <code>Locale</code> you can query it for information

  * about itself. Use <code>getCountry</code> to get the country (or region)

  * code and <code>getLanguage</code> to get the language code.

  * You can use <code>getDisplayCountry</code> to get the

  * name of the country suitable for displaying to the user. Similarly,

  * you can use <code>getDisplayLanguage</code> to get the name of

  * the language suitable for displaying to the user. Interestingly,

  * the <code>getDisplayXXX</code> methods are themselves locale-sensitive

  * and have two versions: one that uses the default locale and one

  * that uses the locale specified as an argument.

  *

  * <p>The Java Platform provides a number of classes that perform locale-sensitive

  * operations. For example, the <code>NumberFormat</code> class formats

  * numbers, currency, and percentages in a locale-sensitive manner. Classes

  * such as <code>NumberFormat</code> have several convenience methods

  * for creating a default object of that type. For example, the

  * <code>NumberFormat</code> class provides these three convenience methods

  * for creating a default <code>NumberFormat</code> object:

  * <blockquote>

  * <pre>

  *     NumberFormat.getInstance()

  *     NumberFormat.getCurrencyInstance()

  *     NumberFormat.getPercentInstance()

  * </pre>

  * </blockquote>

  * Each of these methods has two variants; one with an explicit locale

  * and one without; the latter uses the default locale:

  * <blockquote>

  * <pre>

  *     NumberFormat.getInstance(myLocale)

  *     NumberFormat.getCurrencyInstance(myLocale)

  *     NumberFormat.getPercentInstance(myLocale)

  * </pre>

  * </blockquote>

  * A <code>Locale</code> is the mechanism for identifying the kind of object

  * (<code>NumberFormat</code>) that you would like to get. The locale is

  * <STRONG>just</STRONG> a mechanism for identifying objects,

  * <STRONG>not</STRONG> a container for the objects themselves.

  *

  * <h4>Compatibility</h4>

  *

  * <p>In order to maintain compatibility with existing usage, Locale's

  * constructors retain their behavior prior to the Java Runtime

  * Environment version 1.7.  The same is largely true for the

  * <code>toString</code> method. Thus Locale objects can continue to

  * be used as they were. In particular, clients who parse the output

  * of toString into language, country, and variant fields can continue

  * to do so (although this is strongly discouraged), although the

  * variant field will have additional information in it if script or

  * extensions are present.

  *

  * <p>In addition, BCP 47 imposes syntax restrictions that are not

  * imposed by Locale's constructors. This means that conversions

  * between some Locales and BCP 47 language tags cannot be made without

  * losing information. Thus <code>toLanguageTag</code> cannot

  * represent the state of locales whose language, country, or variant

  * do not conform to BCP 47.

  *

  * <p>Because of these issues, it is recommended that clients migrate

  * away from constructing non-conforming locales and use the

  * <code>forLanguageTag</code> and <code>Locale.Builder</code> APIs instead.

  * Clients desiring a string representation of the complete locale can

  * then always rely on <code>toLanguageTag</code> for this purpose.

  *

  * <h5><a name="special_cases_constructor"/>Special cases</h5>

  *

  * <p>For compatibility reasons, two

  * non-conforming locales are treated as special cases.  These are

  * <b><tt>ja_JP_JP</tt></b> and <b><tt>th_TH_TH</tt></b>. These are ill-formed

  * in BCP 47 since the variants are too short. To ease migration to BCP 47,

  * these are treated specially during construction.  These two cases (and only

  * these) cause a constructor to generate an extension, all other values behave

  * exactly as they did prior to Java 7.

  *

  * <p>Java has used <tt>ja_JP_JP</tt> to represent Japanese as used in

  * Japan together with the Japanese Imperial calendar. This is now

  * representable using a Unicode locale extension, by specifying the

  * Unicode locale key <tt>ca</tt> (for "calendar") and type

  * <tt>japanese</tt>. When the Locale constructor is called with the

  * arguments "ja", "JP", "JP", the extension "u-ca-japanese" is

  * automatically added.

  *

  * <p>Java has used <tt>th_TH_TH</tt> to represent Thai as used in

  * Thailand together with Thai digits. This is also now representable using

  * a Unicode locale extension, by specifying the Unicode locale key

  * <tt>nu</tt> (for "number") and value <tt>thai</tt>. When the Locale

  * constructor is called with the arguments "th", "TH", "TH", the

  * extension "u-nu-thai" is automatically added.

  *

  * <h5>Serialization</h5>

  *

  * <p>During serialization, writeObject writes all fields to the output

  * stream, including extensions.

  *

  * <p>During deserialization, readResolve adds extensions as described

  * in <a href="#special_cases_constructor">Special Cases</a>, only

  * for the two cases th_TH_TH and ja_JP_JP.

  *

  * <h5>Legacy language codes</h5>

  *

  * <p>Locale's constructor has always converted three language codes to

  * their earlier, obsoleted forms: <tt>he</tt> maps to <tt>iw</tt>,

  * <tt>yi</tt> maps to <tt>ji</tt>, and <tt>id</tt> maps to

  * <tt>in</tt>.  This continues to be the case, in order to not break

  * backwards compatibility.

  *

  * <p>The APIs added in 1.7 map between the old and new language codes,

  * maintaining the old codes internal to Locale (so that

  * <code>getLanguage</code> and <code>toString</code> reflect the old

  * code), but using the new codes in the BCP 47 language tag APIs (so

  * that <code>toLanguageTag</code> reflects the new one). This

  * preserves the equivalence between Locales no matter which code or

  * API is used to construct them. Java's default resource bundle

  * lookup mechanism also implements this mapping, so that resources

  * can be named using either convention, see {@link ResourceBundle.Control}.

  *

  * <h5>Three-letter language/country(region) codes</h5>

  *

  * <p>The Locale constructors have always specified that the language

  * and the country param be two characters in length, although in

  * practice they have accepted any length.  The specification has now

  * been relaxed to allow language codes of two to eight characters and

  * country (region) codes of two to three characters, and in

  * particular, three-letter language codes and three-digit region

  * codes as specified in the IANA Language Subtag Registry.  For

  * compatibility, the implementation still does not impose a length

  * constraint.

  *

  * @see Builder

  * @see ResourceBundle

  * @see java.text.Format

  * @see java.text.NumberFormat

  * @see java.text.Collator

  * @author Mark Davis

  * @since 1.1

  */

 public final class Locale implements Cloneable, Serializable {

     static private final  Cache LOCALECACHE = new Cache();

     /** Useful constant for language.

      */

     static public final Locale ENGLISH = createConstant("en", "");

     /** Useful constant for language.

      */

     static public final Locale FRENCH = createConstant("fr", "");

     /** Useful constant for language.

      */

     static public final Locale GERMAN = createConstant("de", "");

     /** Useful constant for language.

      */

     static public final Locale ITALIAN = createConstant("it", "");

     /** Useful constant for language.

      */

     static public final Locale JAPANESE = createConstant("ja", "");

     /** Useful constant for language.

      */

     static public final Locale KOREAN = createConstant("ko", "");

     /** Useful constant for language.

      */

     static public final Locale CHINESE = createConstant("zh", "");

     /** Useful constant for language.

      */

     static public final Locale SIMPLIFIED_CHINESE = createConstant("zh", "CN");

     /** Useful constant for language.

      */

     static public final Locale TRADITIONAL_CHINESE = createConstant("zh", "TW");

     /** Useful constant for country.

      */

     static public final Locale FRANCE = createConstant("fr", "FR");

     /** Useful constant for country.

      */

     static public final Locale GERMANY = createConstant("de", "DE");

     /** Useful constant for country.

      */

     static public final Locale ITALY = createConstant("it", "IT");

     /** Useful constant for country.

      */

     static public final Locale JAPAN = createConstant("ja", "JP");

     /** Useful constant for country.

      */

     static public final Locale KOREA = createConstant("ko", "KR");

     /** Useful constant for country.

      */

     static public final Locale CHINA = SIMPLIFIED_CHINESE;

     /** Useful constant for country.

      */

     static public final Locale PRC = SIMPLIFIED_CHINESE;

     /** Useful constant for country.

      */

     static public final Locale TAIWAN = TRADITIONAL_CHINESE;

     /** Useful constant for country.

      */

     static public final Locale UK = createConstant("en", "GB");

     /** Useful constant for country.

      */

     static public final Locale US = createConstant("en", "US");

     /** Useful constant for country.

      */

     static public final Locale CANADA = createConstant("en", "CA");

     /** Useful constant for country.

      */

     static public final Locale CANADA_FRENCH = createConstant("fr", "CA");

     /**

      * Useful constant for the root locale.  The root locale is the locale whose

      * language, country, and variant are empty ("") strings.  This is regarded

      * as the base locale of all locales, and is used as the language/country

      * neutral locale for the locale sensitive operations.

      *

      * @since 1.6

      */

     static public final Locale ROOT = createConstant("", "");

     /**

      * The key for the private use extension ('x').

      *

      * @see #getExtension(char)

      * @see Builder#setExtension(char, String)

      * @since 1.7

      */

     static public final char PRIVATE_USE_EXTENSION = 'x';

     /**

      * The key for Unicode locale extension ('u').

      *

      * @see #getExtension(char)

      * @see Builder#setExtension(char, String)

      * @since 1.7

      */

     static public final char UNICODE_LOCALE_EXTENSION = 'u';

     /** serialization ID

      */

     static final long serialVersionUID = 9149081749638150636L;

     /**

      * Display types for retrieving localized names from the name providers.

      */

     private static final int DISPLAY_LANGUAGE = 0;

     private static final int DISPLAY_COUNTRY  = 1;

     private static final int DISPLAY_VARIANT  = 2;

     private static final int DISPLAY_SCRIPT   = 3;

     /**

      * Private constructor used by getInstance method

      */

     private Locale(BaseLocale baseLocale, LocaleExtensions extensions) {

         this.baseLocale = baseLocale;

         this.localeExtensions = extensions;

     }

     /**

      * Construct a locale from language, country and variant.

      * This constructor normalizes the language value to lowercase and

      * the country value to uppercase.

      * <p>

      * <b>Note:</b>

      * <ul>

      * <li>ISO 639 is not a stable standard; some of the language codes it defines

      * (specifically "iw", "ji", and "in") have changed.  This constructor accepts both the

      * old codes ("iw", "ji", and "in") and the new codes ("he", "yi", and "id"), but all other

      * API on Locale will return only the OLD codes.

      * <li>For backward compatibility reasons, this constructor does not make

      * any syntactic checks on the input.

      * <li>The two cases ("ja", "JP", "JP") and ("th", "TH", "TH") are handled specially,

      * see <a href="#special_cases_constructor">Special Cases</a> for more information.

      * </ul>

      *

      * @param language An ISO 639 alpha-2 or alpha-3 language code, or a language subtag

      * up to 8 characters in length.  See the <code>Locale</code> class description about

      * valid language values.

      * @param country An ISO 3166 alpha-2 country code or a UN M.49 numeric-3 area code.

      * See the <code>Locale</code> class description about valid country values.

      * @param variant Any arbitrary value used to indicate a variation of a <code>Locale</code>.

      * See the <code>Locale</code> class description for the details.

      * @exception NullPointerException thrown if any argument is null.

      */

     public Locale(String language, String country, String variant) {

         if (language== null || country == null || variant == null) {

             throw new NullPointerException();

         }

         baseLocale = BaseLocale.getInstance(convertOldISOCodes(language), "", country, variant);

         localeExtensions = getCompatibilityExtensions(language, "", country, variant);

     }

     /**

      * Construct a locale from language and country.

      * This constructor normalizes the language value to lowercase and

      * the country value to uppercase.

      * <p>

      * <b>Note:</b>

      * <ul>

      * <li>ISO 639 is not a stable standard; some of the language codes it defines

      * (specifically "iw", "ji", and "in") have changed.  This constructor accepts both the

      * old codes ("iw", "ji", and "in") and the new codes ("he", "yi", and "id"), but all other

      * API on Locale will return only the OLD codes.

      * <li>For backward compatibility reasons, this constructor does not make

      * any syntactic checks on the input.

      * </ul>

      *

      * @param language An ISO 639 alpha-2 or alpha-3 language code, or a language subtag

      * up to 8 characters in length.  See the <code>Locale</code> class description about

      * valid language values.

      * @param country An ISO 3166 alpha-2 country code or a UN M.49 numeric-3 area code.

      * See the <code>Locale</code> class description about valid country values.

      * @exception NullPointerException thrown if either argument is null.

      */

     public Locale(String language, String country) {

         this(language, country, "");

     }

     /**

      * Construct a locale from a language code.

      * This constructor normalizes the language value to lowercase.

      * <p>

      * <b>Note:</b>

      * <ul>

      * <li>ISO 639 is not a stable standard; some of the language codes it defines

      * (specifically "iw", "ji", and "in") have changed.  This constructor accepts both the

      * old codes ("iw", "ji", and "in") and the new codes ("he", "yi", and "id"), but all other

      * API on Locale will return only the OLD codes.

      * <li>For backward compatibility reasons, this constructor does not make

      * any syntactic checks on the input.

      * </ul>

      *

      * @param language An ISO 639 alpha-2 or alpha-3 language code, or a language subtag

      * up to 8 characters in length.  See the <code>Locale</code> class description about

      * valid language values.

      * @exception NullPointerException thrown if argument is null.

      * @since 1.4

      */

     public Locale(String language) {

         this(language, "", "");

     }

     /**

      * This method must be called only for creating the Locale.*

      * constants due to making shortcuts.

      */

     private static Locale createConstant(String lang, String country) {

         BaseLocale base = BaseLocale.createInstance(lang, country);

         return getInstance(base, null);

     }

     /**

      * Returns a <code>Locale</code> constructed from the given

      * <code>language</code>, <code>country</code> and

      * <code>variant</code>. If the same <code>Locale</code> instance

      * is available in the cache, then that instance is

      * returned. Otherwise, a new <code>Locale</code> instance is

      * created and cached.

      *

      * @param language lowercase 2 to 8 language code.

      * @param country uppercase two-letter ISO-3166 code and numric-3 UN M.49 area code.

      * @param variant vendor and browser specific code. See class description.

      * @return the <code>Locale</code> instance requested

      * @exception NullPointerException if any argument is null.

      */

     static Locale getInstance(String language, String country, String variant) {

         return getInstance(language, "", country, variant, null);

     }

     static Locale getInstance(String language, String script, String country,

                                       String variant, LocaleExtensions extensions) {

         if (language== null || script == null || country == null || variant == null) {

             throw new NullPointerException();

         }

         if (extensions == null) {

             extensions = getCompatibilityExtensions(language, script, country, variant);

         }

         BaseLocale baseloc = BaseLocale.getInstance(language, script, country, variant);

         return getInstance(baseloc, extensions);

     }

     static Locale getInstance(BaseLocale baseloc, LocaleExtensions extensions) {

         LocaleKey key = new LocaleKey(baseloc, extensions);

         return LOCALECACHE.get(key);

     }

     private static class Cache extends LocaleObjectCache<LocaleKey, Locale> {

         private Cache() {

         }

         @Override

         protected Locale createObject(LocaleKey key) {

             return new Locale(key.base, key.exts);

         }

     }

     private static final class LocaleKey {

         private final BaseLocale base;

         private final LocaleExtensions exts;

         private final int hash;

         private LocaleKey(BaseLocale baseLocale, LocaleExtensions extensions) {

             base = baseLocale;

             exts = extensions;

             // Calculate the hash value here because it's always used.

             int h = base.hashCode();

             if (exts != null) {

                 h ^= exts.hashCode();

             }

             hash = h;

         }

         @Override

         public boolean equals(Object obj) {

             if (this == obj) {

                 return true;

             }

             if (!(obj instanceof LocaleKey)) {

                 return false;

             }

             LocaleKey other = (LocaleKey)obj;

             if (hash != other.hash || !base.equals(other.base)) {

                 return false;

             }

             if (exts == null) {

                 return other.exts == null;

             }

             return exts.equals(other.exts);

         }

         @Override

         public int hashCode() {

             return hash;

         }

     }

     /**

      * Gets the current value of the default locale for this instance

      * of the Java Virtual Machine.

      * <p>

      * The Java Virtual Machine sets the default locale during startup

      * based on the host environment. It is used by many locale-sensitive

      * methods if no locale is explicitly specified.

      * It can be changed using the

      * {@link #setDefault(java.util.Locale) setDefault} method.

      *

      * @return the default locale for this instance of the Java Virtual Machine

      */

     public static Locale getDefault() {

         // do not synchronize this method - see 4071298

         // it's OK if more than one default locale happens to be created

         if (defaultLocale == null) {

             initDefault();

         }

         return defaultLocale;

     }

     /**

      * Gets the current value of the default locale for the specified Category

      * for this instance of the Java Virtual Machine.

      * <p>

      * The Java Virtual Machine sets the default locale during startup based

      * on the host environment. It is used by many locale-sensitive methods

      * if no locale is explicitly specified. It can be changed using the

      * setDefault(Locale.Category, Locale) method.

      *

      * @param category - the specified category to get the default locale

      * @throws NullPointerException - if category is null

      * @return the default locale for the specified Category for this instance

      *     of the Java Virtual Machine

      * @see #setDefault(Locale.Category, Locale)

      * @since 1.7

      */

     public static Locale getDefault(Locale.Category category) {

         // do not synchronize this method - see 4071298

         // it's OK if more than one default locale happens to be created

         switch (category) {

         case DISPLAY:

             if (defaultDisplayLocale == null) {

                 initDefault(category);

             }

             return defaultDisplayLocale;

         case FORMAT:

             if (defaultFormatLocale == null) {

                 initDefault(category);

             }

             return defaultFormatLocale;

         default:

             assert false: "Unknown Category";

         }

         return getDefault();

     }

     private static void initDefault() {

         String language, region, script, country, variant;

         language = AccessController.doPrivileged(

             new GetPropertyAction("user.language", "en"));

         // for compatibility, check for old user.region property

         region = AccessController.doPrivileged(

             new GetPropertyAction("user.region"));

         if (region != null) {

             // region can be of form country, country_variant, or _variant

             int i = region.indexOf('_');

             if (i >= 0) {

                 country = region.substring(0, i);

                 variant = region.substring(i + 1);

             } else {

                 country = region;

                 variant = "";

             }

             script = "";

         } else {

             script = AccessController.doPrivileged(

                 new GetPropertyAction("user.script", ""));

             country = AccessController.doPrivileged(

                 new GetPropertyAction("user.country", ""));

             variant = AccessController.doPrivileged(

                 new GetPropertyAction("user.variant", ""));

         }

         defaultLocale = getInstance(language, script, country, variant, null);

     }

     private static void initDefault(Locale.Category category) {

         // make sure defaultLocale is initialized

         if (defaultLocale == null) {

             initDefault();

         }

         Locale defaultCategoryLocale = getInstance(

             AccessController.doPrivileged(

                 new GetPropertyAction(category.languageKey, defaultLocale.getLanguage())),

             AccessController.doPrivileged(

                 new GetPropertyAction(category.scriptKey, defaultLocale.getScript())),

             AccessController.doPrivileged(

                 new GetPropertyAction(category.countryKey, defaultLocale.getCountry())),

             AccessController.doPrivileged(

                 new GetPropertyAction(category.variantKey, defaultLocale.getVariant())),

             null);

         switch (category) {

         case DISPLAY:

             defaultDisplayLocale = defaultCategoryLocale;

             break;

         case FORMAT:

             defaultFormatLocale = defaultCategoryLocale;

             break;

         }

     }

     /**

      * Sets the default locale for this instance of the Java Virtual Machine.

      * This does not affect the host locale.

      * <p>

      * If there is a security manager, its <code>checkPermission</code>

      * method is called with a <code>PropertyPermission("user.language", "write")</code>

      * permission before the default locale is changed.

      * <p>

      * The Java Virtual Machine sets the default locale during startup

      * based on the host environment. It is used by many locale-sensitive

      * methods if no locale is explicitly specified.

      * <p>

      * Since changing the default locale may affect many different areas

      * of functionality, this method should only be used if the caller

      * is prepared to reinitialize locale-sensitive code running

      * within the same Java Virtual Machine.

      * <p>

      * By setting the default locale with this method, all of the default

      * locales for each Category are also set to the specified default locale.

      *

      * @throws SecurityException

      *        if a security manager exists and its

      *        <code>checkPermission</code> method doesn't allow the operation.

      * @throws NullPointerException if <code>newLocale</code> is null

      * @param newLocale the new default locale

      * @see SecurityManager#checkPermission

      * @see java.util.PropertyPermission

      */

     public static synchronized void setDefault(Locale newLocale) {

         setDefault(Category.DISPLAY, newLocale);

         setDefault(Category.FORMAT, newLocale);

         defaultLocale = newLocale;

     }

     /**

      * Sets the default locale for the specified Category for this instance

      * of the Java Virtual Machine. This does not affect the host locale.

      * <p>

      * If there is a security manager, its checkPermission method is called

      * with a PropertyPermission("user.language", "write") permission before

      * the default locale is changed.

      * <p>

      * The Java Virtual Machine sets the default locale during startup based

      * on the host environment. It is used by many locale-sensitive methods

      * if no locale is explicitly specified.

      * <p>

      * Since changing the default locale may affect many different areas of

      * functionality, this method should only be used if the caller is

      * prepared to reinitialize locale-sensitive code running within the

      * same Java Virtual Machine.

      * <p>

      *

      * @param category - the specified category to set the default locale

      * @param newLocale - the new default locale

      * @throws SecurityException - if a security manager exists and its

      *     checkPermission method doesn't allow the operation.

      * @throws NullPointerException - if category and/or newLocale is null

      * @see SecurityManager#checkPermission(java.security.Permission)

      * @see PropertyPermission

      * @see #getDefault(Locale.Category)

      * @since 1.7

      */

     public static synchronized void setDefault(Locale.Category category,

         Locale newLocale) {

         if (category == null)

             throw new NullPointerException("Category cannot be NULL");

         if (newLocale == null)

             throw new NullPointerException("Can't set default locale to NULL");

         SecurityManager sm = System.getSecurityManager();

         if (sm != null) sm.checkPermission(new PropertyPermission

                         ("user.language", "write"));

         switch (category) {

         case DISPLAY:

             defaultDisplayLocale = newLocale;

             break;

         case FORMAT:

             defaultFormatLocale = newLocale;

             break;

         default:

             assert false: "Unknown Category";

         }

     }

     /**

      * Returns an array of all installed locales.

      * The returned array represents the union of locales supported

      * by the Java runtime environment and by installed

      * {@link java.util.spi.LocaleServiceProvider LocaleServiceProvider}

      * implementations.  It must contain at least a <code>Locale</code>

      * instance equal to {@link java.util.Locale#US Locale.US}.

      *

      * @return An array of installed locales.

      */

     public static Locale[] getAvailableLocales() {

         return LocaleServiceProviderPool.getAllAvailableLocales();

     }

     /**

      * Returns a list of all 2-letter country codes defined in ISO 3166.

      * Can be used to create Locales.

      * <p>

      * <b>Note:</b> The <code>Locale</code> class also supports other codes for

      * country (region), such as 3-letter numeric UN M.49 area codes.

      * Therefore, the list returned by this method does not contain ALL valid

      * codes that can be used to create Locales.

      */

     public static String[] getISOCountries() {

         if (isoCountries == null) {

             isoCountries = getISO2Table(LocaleISOData.isoCountryTable);

         }

         String[] result = new String[isoCountries.length];

         System.arraycopy(isoCountries, 0, result, 0, isoCountries.length);

         return result;

     }

     /**

      * Returns a list of all 2-letter language codes defined in ISO 639.

      * Can be used to create Locales.

      * <p>

      * <b>Note:</b>

      * <ul>

      * <li>ISO 639 is not a stable standard&mdash; some languages' codes have changed.

      * The list this function returns includes both the new and the old codes for the

      * languages whose codes have changed.

      * <li>The <code>Locale</code> class also supports language codes up to

      * 8 characters in length.  Therefore, the list returned by this method does

      * not contain ALL valid codes that can be used to create Locales.

      * </ul>

      */

     public static String[] getISOLanguages() {

         if (isoLanguages == null) {

             isoLanguages = getISO2Table(LocaleISOData.isoLanguageTable);

         }

         String[] result = new String[isoLanguages.length];

         System.arraycopy(isoLanguages, 0, result, 0, isoLanguages.length);

         return result;

     }

     private static final String[] getISO2Table(String table) {

         int len = table.length() / 5;

         String[] isoTable = new String[len];

         for (int i = 0, j = 0; i < len; i++, j += 5) {

             isoTable[i] = table.substring(j, j + 2);

         }

         return isoTable;

     }

     /**

      * Returns the language code of this Locale.

      *

      * <p><b>Note:</b> ISO 639 is not a stable standard&mdash; some languages' codes have changed.

      * Locale's constructor recognizes both the new and the old codes for the languages

      * whose codes have changed, but this function always returns the old code.  If you

      * want to check for a specific language whose code has changed, don't do

      * <pre>

      * if (locale.getLanguage().equals("he")) // BAD!

      *    ...

      * </pre>

      * Instead, do

      * <pre>

      * if (locale.getLanguage().equals(new Locale("he").getLanguage()))

      *    ...

      * </pre>

      * @return The language code, or the empty string if none is defined.

      * @see #getDisplayLanguage

      */

     public String getLanguage() {

         return baseLocale.getLanguage();

     }

     /**

      * Returns the script for this locale, which should

      * either be the empty string or an ISO 15924 4-letter script

      * code. The first letter is uppercase and the rest are

      * lowercase, for example, 'Latn', 'Cyrl'.

      *

      * @return The script code, or the empty string if none is defined.

      * @see #getDisplayScript

      * @since 1.7

      */

     public String getScript() {

         return baseLocale.getScript();

     }

     /**

      * Returns the country/region code for this locale, which should

      * either be the empty string, an uppercase ISO 3166 2-letter code,

      * or a UN M.49 3-digit code.

      *

      * @return The country/region code, or the empty string if none is defined.

      * @see #getDisplayCountry

      */

     public String getCountry() {

         return baseLocale.getRegion();

     }

     /**

      * Returns the variant code for this locale.

      *

      * @return The variant code, or the empty string if none is defined.

      * @see #getDisplayVariant

      */

     public String getVariant() {

         return baseLocale.getVariant();

     }

     /**

      * Returns the extension (or private use) value associated with

      * the specified key, or null if there is no extension

      * associated with the key. To be well-formed, the key must be one

      * of <code>[0-9A-Za-z]</code>. Keys are case-insensitive, so

      * for example 'z' and 'Z' represent the same extension.

      *

      * @param key the extension key

      * @return The extension, or null if this locale defines no

      * extension for the specified key.

      * @throws IllegalArgumentException if key is not well-formed

      * @see #PRIVATE_USE_EXTENSION

      * @see #UNICODE_LOCALE_EXTENSION

      * @since 1.7

      */

     public String getExtension(char key) {

         if (!LocaleExtensions.isValidKey(key)) {

             throw new IllegalArgumentException("Ill-formed extension key: " + key);

         }

         return (localeExtensions == null) ? null : localeExtensions.getExtensionValue(key);

     }

     /**

      * Returns the set of extension keys associated with this locale, or the

      * empty set if it has no extensions. The returned set is unmodifiable.

      * The keys will all be lower-case.

      *

      * @return The set of extension keys, or the empty set if this locale has

      * no extensions.

      * @since 1.7

      */

     public Set<Character> getExtensionKeys() {

         if (localeExtensions == null) {

             return Collections.emptySet();

         }

         return localeExtensions.getKeys();

     }

     /**

      * Returns the set of unicode locale attributes associated with

      * this locale, or the empty set if it has no attributes. The

      * returned set is unmodifiable.

      *

      * @return The set of attributes.

      * @since 1.7

      */

     public Set<String> getUnicodeLocaleAttributes() {

         if (localeExtensions == null) {

             return Collections.emptySet();

         }

         return localeExtensions.getUnicodeLocaleAttributes();

     }

     /**

      * Returns the Unicode locale type associated with the specified Unicode locale key

      * for this locale. Returns the empty string for keys that are defined with no type.

      * Returns null if the key is not defined. Keys are case-insensitive. The key must

      * be two alphanumeric characters ([0-9a-zA-Z]), or an IllegalArgumentException is

      * thrown.

      *

      * @param key the Unicode locale key

      * @return The Unicode locale type associated with the key, or null if the

      * locale does not define the key.

      * @throws IllegalArgumentException if the key is not well-formed

      * @throws NullPointerException if <code>key</code> is null

      * @since 1.7

      */

     public String getUnicodeLocaleType(String key) {

         if (!UnicodeLocaleExtension.isKey(key)) {

             throw new IllegalArgumentException("Ill-formed Unicode locale key: " + key);

         }

         return (localeExtensions == null) ? null : localeExtensions.getUnicodeLocaleType(key);

     }

     /**

      * Returns the set of Unicode locale keys defined by this locale, or the empty set if

      * this locale has none.  The returned set is immutable.  Keys are all lower case.

      *

      * @return The set of Unicode locale keys, or the empty set if this locale has

      * no Unicode locale keywords.

      * @since 1.7

      */

     public Set<String> getUnicodeLocaleKeys() {

         if (localeExtensions == null) {

             return Collections.emptySet();

         }

         return localeExtensions.getUnicodeLocaleKeys();

     }

     /**

      * Package locale method returning the Locale's BaseLocale,

      * used by ResourceBundle

      * @return base locale of this Locale

      */

     BaseLocale getBaseLocale() {

         return baseLocale;

     }

     /**

      * Package private method returning the Locale's LocaleExtensions,

      * used by ResourceBundle.

      * @return locale exnteions of this Locale,

      *         or {@code null} if no extensions are defined

      */

      LocaleExtensions getLocaleExtensions() {

          return localeExtensions;

      }

     /**

      * Returns a string representation of this <code>Locale</code>

      * object, consisting of language, country, variant, script,

      * and extensions as below:

      * <p><blockquote>

      * language + "_" + country + "_" + (variant + "_#" | "#") + script + "-" + extensions

      * </blockquote>

      *

      * Language is always lower case, country is always upper case, script is always title

      * case, and extensions are always lower case.  Extensions and private use subtags

      * will be in canonical order as explained in {@link #toLanguageTag}.

      *

      * <p>When the locale has neither script nor extensions, the result is the same as in

      * Java 6 and prior.

      *

      * <p>If both the language and country fields are missing, this function will return

      * the empty string, even if the variant, script, or extensions field is present (you

      * can't have a locale with just a variant, the variant must accompany a well-formed

      * language or country code).

      *

      * <p>If script or extensions are present and variant is missing, no underscore is

      * added before the "#".

      *

      * <p>This behavior is designed to support debugging and to be compatible with

      * previous uses of <code>toString</code> that expected language, country, and variant

      * fields only.  To represent a Locale as a String for interchange purposes, use

      * {@link #toLanguageTag}.

      *

      * <p>Examples: <ul><tt>

      * <li>en

      * <li>de_DE

      * <li>_GB

      * <li>en_US_WIN

      * <li>de__POSIX

      * <li>zh_CN_#Hans

      * <li>zh_TW_#Hant-x-java

      * <li>th_TH_TH_#u-nu-thai</tt></ul>

      *

      * @return A string representation of the Locale, for debugging.

      * @see #getDisplayName

      * @see #toLanguageTag

      */

     @Override

     public final String toString() {

         boolean l = (baseLocale.getLanguage().length() != 0);

         boolean s = (baseLocale.getScript().length() != 0);

         boolean r = (baseLocale.getRegion().length() != 0);

         boolean v = (baseLocale.getVariant().length() != 0);

         boolean e = (localeExtensions != null && localeExtensions.getID().length() != 0);

         StringBuilder result = new StringBuilder(baseLocale.getLanguage());

         if (r || (l && (v || s || e))) {

             result.append('_')

                 .append(baseLocale.getRegion()); // This may just append '_'

         }

         if (v && (l || r)) {

             result.append('_')

                 .append(baseLocale.getVariant());

         }

         if (s && (l || r)) {

             result.append("_#")

                 .append(baseLocale.getScript());

         }

         if (e && (l || r)) {

             result.append('_');

             if (!s) {

                 result.append('#');

             }

             result.append(localeExtensions.getID());

         }

         return result.toString();

     }

     /**

      * Returns a well-formed IETF BCP 47 language tag representing

      * this locale.

      *

      * <p>If this <code>Locale</code> has a language, country, or

      * variant that does not satisfy the IETF BCP 47 language tag

      * syntax requirements, this method handles these fields as

      * described below:

      *

      * <p><b>Language:</b> If language is empty, or not <a

      * href="#def_language" >well-formed</a> (for example "a" or

      * "e2"), it will be emitted as "und" (Undetermined).

      *

      * <p><b>Country:</b> If country is not <a

      * href="#def_region">well-formed</a> (for example "12" or "USA"),

      * it will be omitted.

      *

      * <p><b>Variant:</b> If variant <b>is</b> <a

      * href="#def_variant">well-formed</a>, each sub-segment

      * (delimited by '-' or '_') is emitted as a subtag.  Otherwise:

      * <ul>

      *

      * <li>if all sub-segments match <code>[0-9a-zA-Z]{1,8}</code>

      * (for example "WIN" or "Oracle_JDK_Standard_Edition"), the first

      * ill-formed sub-segment and all following will be appended to

      * the private use subtag.  The first appended subtag will be

      * "lvariant", followed by the sub-segments in order, separated by

      * hyphen. For example, "x-lvariant-WIN",

      * "Oracle-x-lvariant-JDK-Standard-Edition".

      *

      * <li>if any sub-segment does not match

      * <code>[0-9a-zA-Z]{1,8}</code>, the variant will be truncated

      * and the problematic sub-segment and all following sub-segments

      * will be omitted.  If the remainder is non-empty, it will be

      * emitted as a private use subtag as above (even if the remainder

      * turns out to be well-formed).  For example,

      * "Solaris_isjustthecoolestthing" is emitted as

      * "x-lvariant-Solaris", not as "solaris".</li></ul>

      *

      * <p><b>Special Conversions:</b> Java supports some old locale

      * representations, including deprecated ISO language codes,

      * for compatibility. This method performs the following

      * conversions:

      * <ul>

      *

      * <li>Deprecated ISO language codes "iw", "ji", and "in" are

      * converted to "he", "yi", and "id", respectively.

      *

      * <li>A locale with language "no", country "NO", and variant

      * "NY", representing Norwegian Nynorsk (Norway), is converted

      * to a language tag "nn-NO".</li></ul>

      *

      * <p><b>Note:</b> Although the language tag created by this

      * method is well-formed (satisfies the syntax requirements

      * defined by the IETF BCP 47 specification), it is not

      * necessarily a valid BCP 47 language tag.  For example,

      * <pre>

      *   new Locale("xx", "YY").toLanguageTag();</pre>

      *

      * will return "xx-YY", but the language subtag "xx" and the

      * region subtag "YY" are invalid because they are not registered

      * in the IANA Language Subtag Registry.

      *

      * @return a BCP47 language tag representing the locale

      * @see #forLanguageTag(String)

      * @since 1.7

      */

     public String toLanguageTag() {

         LanguageTag tag = LanguageTag.parseLocale(baseLocale, localeExtensions);

         StringBuilder buf = new StringBuilder();

         String subtag = tag.getLanguage();

         if (subtag.length() > 0) {

             buf.append(LanguageTag.canonicalizeLanguage(subtag));

         }

         subtag = tag.getScript();

         if (subtag.length() > 0) {

             buf.append(LanguageTag.SEP);

             buf.append(LanguageTag.canonicalizeScript(subtag));

         }

         subtag = tag.getRegion();

         if (subtag.length() > 0) {

             buf.append(LanguageTag.SEP);

             buf.append(LanguageTag.canonicalizeRegion(subtag));

         }

         List<String>subtags = tag.getVariants();

         for (String s : subtags) {

             buf.append(LanguageTag.SEP);

             // preserve casing

             buf.append(s);

         }

         subtags = tag.getExtensions();

         for (String s : subtags) {

             buf.append(LanguageTag.SEP);

             buf.append(LanguageTag.canonicalizeExtension(s));

         }

         subtag = tag.getPrivateuse();

         if (subtag.length() > 0) {

             if (buf.length() > 0) {

                 buf.append(LanguageTag.SEP);

             }

             buf.append(LanguageTag.PRIVATEUSE).append(LanguageTag.SEP);

             // preserve casing

             buf.append(subtag);

         }

         return buf.toString();

     }

     /**

      * Returns a locale for the specified IETF BCP 47 language tag string.

      *

      * <p>If the specified language tag contains any ill-formed subtags,

      * the first such subtag and all following subtags are ignored.  Compare

      * to {@link Locale.Builder#setLanguageTag} which throws an exception

      * in this case.

      *

      * <p>The following <b>conversions</b> are performed:<ul>

      *

      * <li>The language code "und" is mapped to language "".

      *

      * <li>The language codes "he", "yi", and "id" are mapped to "iw",

      * "ji", and "in" respectively. (This is the same canonicalization

      * that's done in Locale's constructors.)

      *

      * <li>The portion of a private use subtag prefixed by "lvariant",

      * if any, is removed and appended to the variant field in the

      * result locale (without case normalization).  If it is then

      * empty, the private use subtag is discarded:

      *

      * <pre>

      *     Locale loc;

      *     loc = Locale.forLanguageTag("en-US-x-lvariant-POSIX");

      *     loc.getVariant(); // returns "POSIX"

      *     loc.getExtension('x'); // returns null

      *

      *     loc = Locale.forLanguageTag("de-POSIX-x-URP-lvariant-Abc-Def");

      *     loc.getVariant(); // returns "POSIX_Abc_Def"

      *     loc.getExtension('x'); // returns "urp"

      * </pre>

      *

      * <li>When the languageTag argument contains an extlang subtag,

      * the first such subtag is used as the language, and the primary

      * language subtag and other extlang subtags are ignored:

      *

      * <pre>

      *     Locale.forLanguageTag("ar-aao").getLanguage(); // returns "aao"

      *     Locale.forLanguageTag("en-abc-def-us").toString(); // returns "abc_US"

      * </pre>

      *

      * <li>Case is normalized except for variant tags, which are left

      * unchanged.  Language is normalized to lower case, script to

      * title case, country to upper case, and extensions to lower

      * case.

      *

      * <li>If, after processing, the locale would exactly match either

      * ja_JP_JP or th_TH_TH with no extensions, the appropriate

      * extensions are added as though the constructor had been called:

      *

      * <pre>

      *    Locale.forLanguageTag("ja-JP-x-lvariant-JP").toLanguageTag();

      *    // returns "ja-JP-u-ca-japanese-x-lvariant-JP"

      *    Locale.forLanguageTag("th-TH-x-lvariant-TH").toLanguageTag();

      *    // returns "th-TH-u-nu-thai-x-lvariant-TH"

      * <pre></ul>

      *

      * <p>This implements the 'Language-Tag' production of BCP47, and

      * so supports grandfathered (regular and irregular) as well as

      * private use language tags.  Stand alone private use tags are

      * represented as empty language and extension 'x-whatever',

      * and grandfathered tags are converted to their canonical replacements

      * where they exist.

      *

      * <p>Grandfathered tags with canonical replacements are as follows:

      *

      * <table>

      * <tbody align="center">

      * <tr><th>grandfathered tag</th><th>&nbsp;</th><th>modern replacement</th></tr>

      * <tr><td>art-lojban</td><td>&nbsp;</td><td>jbo</td></tr>

      * <tr><td>i-ami</td><td>&nbsp;</td><td>ami</td></tr>

      * <tr><td>i-bnn</td><td>&nbsp;</td><td>bnn</td></tr>

      * <tr><td>i-hak</td><td>&nbsp;</td><td>hak</td></tr>

      * <tr><td>i-klingon</td><td>&nbsp;</td><td>tlh</td></tr>

      * <tr><td>i-lux</td><td>&nbsp;</td><td>lb</td></tr>

      * <tr><td>i-navajo</td><td>&nbsp;</td><td>nv</td></tr>

      * <tr><td>i-pwn</td><td>&nbsp;</td><td>pwn</td></tr>

      * <tr><td>i-tao</td><td>&nbsp;</td><td>tao</td></tr>

      * <tr><td>i-tay</td><td>&nbsp;</td><td>tay</td></tr>

      * <tr><td>i-tsu</td><td>&nbsp;</td><td>tsu</td></tr>

      * <tr><td>no-bok</td><td>&nbsp;</td><td>nb</td></tr>

      * <tr><td>no-nyn</td><td>&nbsp;</td><td>nn</td></tr>

      * <tr><td>sgn-BE-FR</td><td>&nbsp;</td><td>sfb</td></tr>

      * <tr><td>sgn-BE-NL</td><td>&nbsp;</td><td>vgt</td></tr>

      * <tr><td>sgn-CH-DE</td><td>&nbsp;</td><td>sgg</td></tr>

      * <tr><td>zh-guoyu</td><td>&nbsp;</td><td>cmn</td></tr>

      * <tr><td>zh-hakka</td><td>&nbsp;</td><td>hak</td></tr>

      * <tr><td>zh-min-nan</td><td>&nbsp;</td><td>nan</td></tr>

      * <tr><td>zh-xiang</td><td>&nbsp;</td><td>hsn</td></tr>

      * </tbody>

      * </table>

      *

      * <p>Grandfathered tags with no modern replacement will be

      * converted as follows:

      *

      * <table>

      * <tbody align="center">

      * <tr><th>grandfathered tag</th><th>&nbsp;</th><th>converts to</th></tr>

      * <tr><td>cel-gaulish</td><td>&nbsp;</td><td>xtg-x-cel-gaulish</td></tr>

      * <tr><td>en-GB-oed</td><td>&nbsp;</td><td>en-GB-x-oed</td></tr>

      * <tr><td>i-default</td><td>&nbsp;</td><td>en-x-i-default</td></tr>

      * <tr><td>i-enochian</td><td>&nbsp;</td><td>und-x-i-enochian</td></tr>

      * <tr><td>i-mingo</td><td>&nbsp;</td><td>see-x-i-mingo</td></tr>

      * <tr><td>zh-min</td><td>&nbsp;</td><td>nan-x-zh-min</td></tr>

      * </tbody>

      * </table>

      *

      * <p>For a list of all grandfathered tags, see the

      * IANA Language Subtag Registry (search for "Type: grandfathered").

      *

      * <p><b>Note</b>: there is no guarantee that <code>toLanguageTag</code>

      * and <code>forLanguageTag</code> will round-trip.

      *

      * @param languageTag the language tag

      * @return The locale that best represents the language tag.

      * @throws NullPointerException if <code>languageTag</code> is <code>null</code>

      * @see #toLanguageTag()

      * @see java.util.Locale.Builder#setLanguageTag(String)

      * @since 1.7

      */

     public static Locale forLanguageTag(String languageTag) {

         LanguageTag tag = LanguageTag.parse(languageTag, null);

         InternalLocaleBuilder bldr = new InternalLocaleBuilder();

         bldr.setLanguageTag(tag);

         BaseLocale base = bldr.getBaseLocale();

         LocaleExtensions exts = bldr.getLocaleExtensions();

         if (exts == null && base.getVariant().length() > 0) {

             exts = getCompatibilityExtensions(base.getLanguage(), base.getScript(),

                                               base.getRegion(), base.getVariant());

         }

         return getInstance(base, exts);

     }

     /**

      * Returns a three-letter abbreviation of this locale's language.

      * If the language matches an ISO 639-1 two-letter code, the

      * corresponding ISO 639-2/T three-letter lowercase code is

      * returned.  The ISO 639-2 language codes can be found on-line,

      * see "Codes for the Representation of Names of Languages Part 2:

      * Alpha-3 Code".  If the locale specifies a three-letter

      * language, the language is returned as is.  If the locale does

      * not specify a language the empty string is returned.

      *

      * @return A three-letter abbreviation of this locale's language.

      * @exception MissingResourceException Throws MissingResourceException if

      * three-letter language abbreviation is not available for this locale.

      */

     public String getISO3Language() throws MissingResourceException {

         String lang = baseLocale.getLanguage();

         if (lang.length() == 3) {

             return lang;

         }

         String language3 = getISO3Code(lang, LocaleISOData.isoLanguageTable);

         if (language3 == null) {

             throw new MissingResourceException("Couldn't find 3-letter language code for "

                     + lang, "FormatData_" + toString(), "ShortLanguage");

         }

         return language3;

     }

     /**

      * Returns a three-letter abbreviation for this locale's country.

      * If the country matches an ISO 3166-1 alpha-2 code, the

      * corresponding ISO 3166-1 alpha-3 uppercase code is returned.

      * If the locale doesn't specify a country, this will be the empty

      * string.

      *

      * <p>The ISO 3166-1 codes can be found on-line.

      *

      * @return A three-letter abbreviation of this locale's country.

      * @exception MissingResourceException Throws MissingResourceException if the

      * three-letter country abbreviation is not available for this locale.

      */

     public String getISO3Country() throws MissingResourceException {

         String country3 = getISO3Code(baseLocale.getRegion(), LocaleISOData.isoCountryTable);

         if (country3 == null) {

             throw new MissingResourceException("Couldn't find 3-letter country code for "

                     + baseLocale.getRegion(), "FormatData_" + toString(), "ShortCountry");

         }

         return country3;

     }

     private static final String getISO3Code(String iso2Code, String table) {

         int codeLength = iso2Code.length();

         if (codeLength == 0) {

             return "";

         }

         int tableLength = table.length();

         int index = tableLength;

         if (codeLength == 2) {

             char c1 = iso2Code.charAt(0);

             char c2 = iso2Code.charAt(1);

             for (index = 0; index < tableLength; index += 5) {

                 if (table.charAt(index) == c1

                     && table.charAt(index + 1) == c2) {

                     break;

                 }

             }

         }

         return index < tableLength ? table.substring(index + 2, index + 5) : null;

     }

     /**

      * Returns a name for the locale's language that is appropriate for display to the

      * user.

      * If possible, the name returned will be localized for the default locale.

      * For example, if the locale is fr_FR and the default locale

      * is en_US, getDisplayLanguage() will return "French"; if the locale is en_US and

      * the default locale is fr_FR, getDisplayLanguage() will return "anglais".

      * If the name returned cannot be localized for the default locale,

      * (say, we don't have a Japanese name for Croatian),

      * this function falls back on the English name, and uses the ISO code as a last-resort

      * value.  If the locale doesn't specify a language, this function returns the empty string.

      */

     public final String getDisplayLanguage() {

         return getDisplayLanguage(getDefault(Category.DISPLAY));

     }

     /**

      * Returns a name for the locale's language that is appropriate for display to the

      * user.

      * If possible, the name returned will be localized according to inLocale.

      * For example, if the locale is fr_FR and inLocale

      * is en_US, getDisplayLanguage() will return "French"; if the locale is en_US and

      * inLocale is fr_FR, getDisplayLanguage() will return "anglais".

      * If the name returned cannot be localized according to inLocale,

      * (say, we don't have a Japanese name for Croatian),

      * this function falls back on the English name, and finally

      * on the ISO code as a last-resort value.  If the locale doesn't specify a language,

      * this function returns the empty string.

      *

      * @exception NullPointerException if <code>inLocale</code> is <code>null</code>

      */

     public String getDisplayLanguage(Locale inLocale) {

         return getDisplayString(baseLocale.getLanguage(), inLocale, DISPLAY_LANGUAGE);

     }

     /**

      * Returns a name for the the locale's script that is appropriate for display to

      * the user. If possible, the name will be localized for the default locale.  Returns

      * the empty string if this locale doesn't specify a script code.

      *

      * @return the display name of the script code for the current default locale

      * @since 1.7

      */

     public String getDisplayScript() {

         return getDisplayScript(getDefault());

     }

     /**

      * Returns a name for the locale's script that is appropriate

      * for display to the user. If possible, the name will be

      * localized for the given locale. Returns the empty string if

      * this locale doesn't specify a script code.

      *

      * @return the display name of the script code for the current default locale

      * @throws NullPointerException if <code>inLocale</code> is <code>null</code>

      * @since 1.7

      */

     public String getDisplayScript(Locale inLocale) {

         return getDisplayString(baseLocale.getScript(), inLocale, DISPLAY_SCRIPT);

     }

     /**

      * Returns a name for the locale's country that is appropriate for display to the

      * user.

      * If possible, the name returned will be localized for the default locale.

      * For example, if the locale is fr_FR and the default locale

      * is en_US, getDisplayCountry() will return "France"; if the locale is en_US and

      * the default locale is fr_FR, getDisplayCountry() will return "Etats-Unis".

      * If the name returned cannot be localized for the default locale,

      * (say, we don't have a Japanese name for Croatia),

      * this function falls back on the English name, and uses the ISO code as a last-resort

      * value.  If the locale doesn't specify a country, this function returns the empty string.

      */

     public final String getDisplayCountry() {

         return getDisplayCountry(getDefault(Category.DISPLAY));

     }

     /**

      * Returns a name for the locale's country that is appropriate for display to the

      * user.

      * If possible, the name returned will be localized according to inLocale.

      * For example, if the locale is fr_FR and inLocale

      * is en_US, getDisplayCountry() will return "France"; if the locale is en_US and

      * inLocale is fr_FR, getDisplayCountry() will return "Etats-Unis".

      * If the name returned cannot be localized according to inLocale.

      * (say, we don't have a Japanese name for Croatia),

      * this function falls back on the English name, and finally

      * on the ISO code as a last-resort value.  If the locale doesn't specify a country,

      * this function returns the empty string.

      *

      * @exception NullPointerException if <code>inLocale</code> is <code>null</code>

      */

     public String getDisplayCountry(Locale inLocale) {

         return getDisplayString(baseLocale.getRegion(), inLocale, DISPLAY_COUNTRY);

     }

     private String getDisplayString(String code, Locale inLocale, int type) {

         if (code.length() == 0) {

             return "";

         }

         if (inLocale == null) {

             throw new NullPointerException();

         }

         try {

             OpenListResourceBundle bundle = LocaleData.getLocaleNames(inLocale);

             String key = (type == DISPLAY_VARIANT ? "%%"+code : code);

             String result = null;

             // Check whether a provider can provide an implementation that's closer

             // to the requested locale than what the Java runtime itself can provide.

             LocaleServiceProviderPool pool =

                 LocaleServiceProviderPool.getPool(LocaleNameProvider.class);

             if (pool.hasProviders()) {

                 result = pool.getLocalizedObject(

                                     LocaleNameGetter.INSTANCE,

                                     inLocale, bundle, key,

                                     type, code);

             }

             if (result == null) {

                 result = bundle.getString(key);

             }

             if (result != null) {

                 return result;

             }

         }

         catch (Exception e) {

             // just fall through

         }

         return code;

     }

     /**

      * Returns a name for the locale's variant code that is appropriate for display to the

      * user.  If possible, the name will be localized for the default locale.  If the locale

      * doesn't specify a variant code, this function returns the empty string.

      */

     public final String getDisplayVariant() {

         return getDisplayVariant(getDefault(Category.DISPLAY));

     }

     /**

      * Returns a name for the locale's variant code that is appropriate for display to the

      * user.  If possible, the name will be localized for inLocale.  If the locale

      * doesn't specify a variant code, this function returns the empty string.

      *

      * @exception NullPointerException if <code>inLocale</code> is <code>null</code>

      */

     public String getDisplayVariant(Locale inLocale) {

         if (baseLocale.getVariant().length() == 0)

             return "";

         OpenListResourceBundle bundle = LocaleData.getLocaleNames(inLocale);

         String names[] = getDisplayVariantArray(bundle, inLocale);

         // Get the localized patterns for formatting a list, and use

         // them to format the list.

         String listPattern = null;

         String listCompositionPattern = null;

         try {

             listPattern = bundle.getString("ListPattern");

             listCompositionPattern = bundle.getString("ListCompositionPattern");

         } catch (MissingResourceException e) {

         }

         return formatList(names, listPattern, listCompositionPattern);

     }

     /**

      * Returns a name for the locale that is appropriate for display to the

      * user. This will be the values returned by getDisplayLanguage(),

      * getDisplayScript(), getDisplayCountry(), and getDisplayVariant() assembled

      * into a single string. The the non-empty values are used in order,

      * with the second and subsequent names in parentheses.  For example:

      * <blockquote>

      * language (script, country, variant)<br>

      * language (country)<br>

      * language (variant)<br>

      * script (country)<br>

      * country<br>

      * </blockquote>

      * depending on which fields are specified in the locale.  If the

      * language, sacript, country, and variant fields are all empty,

      * this function returns the empty string.

      */

     public final String getDisplayName() {

         return getDisplayName(getDefault(Category.DISPLAY));

     }

     /**

      * Returns a name for the locale that is appropriate for display

      * to the user.  This will be the values returned by

      * getDisplayLanguage(), getDisplayScript(),getDisplayCountry(),

      * and getDisplayVariant() assembled into a single string.

      * The non-empty values are used in order,

      * with the second and subsequent names in parentheses.  For example:

      * <blockquote>

      * language (script, country, variant)<br>

      * language (country)<br>

      * language (variant)<br>

      * script (country)<br>

      * country<br>

      * </blockquote>

      * depending on which fields are specified in the locale.  If the

      * language, script, country, and variant fields are all empty,

      * this function returns the empty string.

      *

      * @throws NullPointerException if <code>inLocale</code> is <code>null</code>

      */

     public String getDisplayName(Locale inLocale) {

         OpenListResourceBundle bundle = LocaleData.getLocaleNames(inLocale);

         String languageName = getDisplayLanguage(inLocale);

         String scriptName = getDisplayScript(inLocale);

         String countryName = getDisplayCountry(inLocale);

         String[] variantNames = getDisplayVariantArray(bundle, inLocale);

         // Get the localized patterns for formatting a display name.

         String displayNamePattern = null;

         String listPattern = null;

         String listCompositionPattern = null;

         try {

             displayNamePattern = bundle.getString("DisplayNamePattern");

             listPattern = bundle.getString("ListPattern");

             listCompositionPattern = bundle.getString("ListCompositionPattern");

         } catch (MissingResourceException e) {

         }

         // The display name consists of a main name, followed by qualifiers.

         // Typically, the format is "MainName (Qualifier, Qualifier)" but this

         // depends on what pattern is stored in the display locale.

         String   mainName       = null;

         String[] qualifierNames = null;

         // The main name is the language, or if there is no language, the script,

         // then if no script, the country. If there is no language/script/country

         // (an anomalous situation) then the display name is simply the variant's

         // display name.

         if (languageName.length() == 0 && scriptName.length() == 0 && countryName.length() == 0) {

             if (variantNames.length == 0) {

                 return "";

             } else {

                 return formatList(variantNames, listPattern, listCompositionPattern);

             }

         }

         ArrayList<String> names = new ArrayList<>(4);

         if (languageName.length() != 0) {

             names.add(languageName);

         }

         if (scriptName.length() != 0) {

             names.add(scriptName);

         }

         if (countryName.length() != 0) {

             names.add(countryName);

         }

         if (variantNames.length != 0) {

             for (String var : variantNames) {

                 names.add(var);

             }

         }

         // The first one in the main name

         mainName = names.get(0);

         // Others are qualifiers

         int numNames = names.size();

         qualifierNames = (numNames > 1) ?

                 names.subList(1, numNames).toArray(new String[numNames - 1]) : new String[0];

         // Create an array whose first element is the number of remaining

         // elements.  This serves as a selector into a ChoiceFormat pattern from

         // the resource.  The second and third elements are the main name and

         // the qualifier; if there are no qualifiers, the third element is

         // unused by the format pattern.

         Object[] displayNames = {

             new Integer(qualifierNames.length != 0 ? 2 : 1),

             mainName,

             // We could also just call formatList() and have it handle the empty

             // list case, but this is more efficient, and we want it to be

             // efficient since all the language-only locales will not have any

             // qualifiers.

             qualifierNames.length != 0 ? formatList(qualifierNames, listPattern, listCompositionPattern) : null

         };

         if (displayNamePattern != null) {

             return new MessageFormat(displayNamePattern).format(displayNames);

         }

         else {

             // If we cannot get the message format pattern, then we use a simple

             // hard-coded pattern.  This should not occur in practice unless the

             // installation is missing some core files (FormatData etc.).

             StringBuilder result = new StringBuilder();

             result.append((String)displayNames[1]);

             if (displayNames.length > 2) {

                 result.append(" (");

                 result.append((String)displayNames[2]);

                 result.append(')');

             }

             return result.toString();

         }

     }

     /**

      * Overrides Cloneable.

      */

     public Object clone()

     {

         try {

             Locale that = (Locale)super.clone();

             return that;

         } catch (CloneNotSupportedException e) {

             throw new InternalError();

         }

     }

     /**

      * Override hashCode.

      * Since Locales are often used in hashtables, caches the value

      * for speed.

      */

     @Override

     public int hashCode() {

         int hc = hashCodeValue;

         if (hc == 0) {

             hc = baseLocale.hashCode();

             if (localeExtensions != null) {

                 hc ^= localeExtensions.hashCode();

             }

             hashCodeValue = hc;

         }

         return hc;

     }

     // Overrides

     /**

      * Returns true if this Locale is equal to another object.  A Locale is

      * deemed equal to another Locale with identical language, script, country,

      * variant and extensions, and unequal to all other objects.

      *

      * @return true if this Locale is equal to the specified object.

      */

     @Override

     public boolean equals(Object obj) {

         if (this == obj)                      // quick check

             return true;

         if (!(obj instanceof Locale))

             return false;

         BaseLocale otherBase = ((Locale)obj).baseLocale;

         if (!baseLocale.equals(otherBase)) {

             return false;

         }

         if (localeExtensions == null) {

             return ((Locale)obj).localeExtensions == null;

         }

         return localeExtensions.equals(((Locale)obj).localeExtensions);

     }

     // ================= privates =====================================

     private transient BaseLocale baseLocale;

     private transient LocaleExtensions localeExtensions;

     /**

      * Calculated hashcode

      */

     private transient volatile int hashCodeValue = 0;

     private static Locale defaultLocale = null;

     private static Locale defaultDisplayLocale = null;

     private static Locale defaultFormatLocale = null;

     /**

      * Return an array of the display names of the variant.

      * @param bundle the ResourceBundle to use to get the display names

      * @return an array of display names, possible of zero length.

      */

     private String[] getDisplayVariantArray(OpenListResourceBundle bundle, Locale inLocale) {

         // Split the variant name into tokens separated by '_'.

         StringTokenizer tokenizer = new StringTokenizer(baseLocale.getVariant(), "_");

         String[] names = new String[tokenizer.countTokens()];

         // For each variant token, lookup the display name.  If

         // not found, use the variant name itself.

         for (int i=0; i<names.length; ++i) {

             names[i] = getDisplayString(tokenizer.nextToken(),

                                 inLocale, DISPLAY_VARIANT);

         }

         return names;

     }

     /**

      * Format a list using given pattern strings.

      * If either of the patterns is null, then a the list is

      * formatted by concatenation with the delimiter ','.

      * @param stringList the list of strings to be formatted.

      * @param listPattern should create a MessageFormat taking 0-3 arguments

      * and formatting them into a list.

      * @param listCompositionPattern should take 2 arguments

      * and is used by composeList.

      * @return a string representing the list.

      */

     private static String formatList(String[] stringList, String listPattern, String listCompositionPattern) {

         // If we have no list patterns, compose the list in a simple,

         // non-localized way.

         if (listPattern == null || listCompositionPattern == null) {

             StringBuffer result = new StringBuffer();

             for (int i=0; i<stringList.length; ++i) {

                 if (i>0) result.append(',');

                 result.append(stringList[i]);

             }

             return result.toString();

         }

         // Compose the list down to three elements if necessary

         if (stringList.length > 3) {

             MessageFormat format = new MessageFormat(listCompositionPattern);

             stringList = composeList(format, stringList);

         }

         // Rebuild the argument list with the list length as the first element

         Object[] args = new Object[stringList.length + 1];

         System.arraycopy(stringList, 0, args, 1, stringList.length);

         args[0] = new Integer(stringList.length);

         // Format it using the pattern in the resource

         MessageFormat format = new MessageFormat(listPattern);

         return format.format(args);

     }

     /**

      * Given a list of strings, return a list shortened to three elements.

      * Shorten it by applying the given format to the first two elements

      * recursively.

      * @param format a format which takes two arguments

      * @param list a list of strings

      * @return if the list is three elements or shorter, the same list;

      * otherwise, a new list of three elements.

      */

     private static String[] composeList(MessageFormat format, String[] list) {

         if (list.length <= 3) return list;

         // Use the given format to compose the first two elements into one

         String[] listItems = { list[0], list[1] };

         String newItem = format.format(listItems);

         // Form a new list one element shorter

         String[] newList = new String[list.length-1];

         System.arraycopy(list, 2, newList, 1, newList.length-1);

         newList[0] = newItem;

         // Recurse

         return composeList(format, newList);

     }

     /**

      * @serialField language    String

      *      language subtag in lower case. (See <a href="java/util/Locale.html#getLanguage()">getLanguage()</a>)

      * @serialField country     String

      *      country subtag in upper case. (See <a href="java/util/Locale.html#getCountry()">getCountry()</a>)

      * @serialField variant     String

      *      variant subtags separated by LOWLINE characters. (See <a href="java/util/Locale.html#getVariant()">getVariant()</a>)

      * @serialField hashcode    int

      *      deprecated, for forward compatibility only

      * @serialField script      String

      *      script subtag in title case (See <a href="java/util/Locale.html#getScript()">getScript()</a>)

      * @serialField extensions  String

      *      canonical representation of extensions, that is,

      *      BCP47 extensions in alphabetical order followed by

      *      BCP47 private use subtags, all in lower case letters

      *      separated by HYPHEN-MINUS characters.

      *      (See <a href="java/util/Locale.html#getExtensionKeys()">getExtensionKeys()</a>,

      *      <a href="java/util/Locale.html#getExtension(char)">getExtension(char)</a>)

      */

     private static final ObjectStreamField[] serialPersistentFields = {

         new ObjectStreamField("language", String.class),

         new ObjectStreamField("country", String.class),

         new ObjectStreamField("variant", String.class),

         new ObjectStreamField("hashcode", int.class),

         new ObjectStreamField("script", String.class),

         new ObjectStreamField("extensions", String.class),

     };

     /**

      * Serializes this <code>Locale</code> to the specified <code>ObjectOutputStream</code>.

      * @param out the <code>ObjectOutputStream</code> to write

      * @throws IOException

      * @since 1.7

      */

     private void writeObject(ObjectOutputStream out) throws IOException {

         ObjectOutputStream.PutField fields = out.putFields();

         fields.put("language", baseLocale.getLanguage());

         fields.put("script", baseLocale.getScript());

         fields.put("country", baseLocale.getRegion());

         fields.put("variant", baseLocale.getVariant());

         fields.put("extensions", localeExtensions == null ? "" : localeExtensions.getID());

         fields.put("hashcode", -1); // place holder just for backward support

         out.writeFields();

     }

     /**

      * Deserializes this <code>Locale</code>.

      * @param in the <code>ObjectInputStream</code> to read

      * @throws IOException

      * @throws ClassNotFoundException

      * @throws IllformdLocaleException

      * @since 1.7

      */

     private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {

         ObjectInputStream.GetField fields = in.readFields();

         String language = (String)fields.get("language", "");

         String script = (String)fields.get("script", "");

         String country = (String)fields.get("country", "");

         String variant = (String)fields.get("variant", "");

         String extStr = (String)fields.get("extensions", "");

         baseLocale = BaseLocale.getInstance(convertOldISOCodes(language), script, country, variant);

         if (extStr.length() > 0) {

             try {

                 InternalLocaleBuilder bldr = new InternalLocaleBuilder();

                 bldr.setExtensions(extStr);

                 localeExtensions = bldr.getLocaleExtensions();

             } catch (LocaleSyntaxException e) {

                 throw new IllformedLocaleException(e.getMessage());

             }

         } else {

             localeExtensions = null;

         }

     }

     /**

      * Returns a cached <code>Locale</code> instance equivalent to

      * the deserialized <code>Locale</code>. When serialized

      * language, country and variant fields read from the object data stream

      * are exactly "ja", "JP", "JP" or "th", "TH", "TH" and script/extensions

      * fields are empty, this method supplies <code>UNICODE_LOCALE_EXTENSION</code>

      * "ca"/"japanese" (calendar type is "japanese") or "nu"/"thai" (number script

      * type is "thai"). See <a href="Locale.html#special_cases_constructor"/>Special Cases</a>

      * for more information.

      *

      * @return an instance of <code>Locale</code> equivalent to

      * the deserialized <code>Locale</code>.

      * @throws java.io.ObjectStreamException

      */

     private Object readResolve() throws java.io.ObjectStreamException {

         return getInstance(baseLocale.getLanguage(), baseLocale.getScript(),

                 baseLocale.getRegion(), baseLocale.getVariant(), localeExtensions);

     }

     private static volatile String[] isoLanguages = null;

     private static volatile String[] isoCountries = null;

     private static String convertOldISOCodes(String language) {

         // we accept both the old and the new ISO codes for the languages whose ISO

         // codes have changed, but we always store the OLD code, for backward compatibility

         language = LocaleUtils.toLowerString(language).intern();

         if (language == "he") {

             return "iw";

         } else if (language == "yi") {

             return "ji";

         } else if (language == "id") {

             return "in";

         } else {

             return language;

         }

     }

     private static LocaleExtensions getCompatibilityExtensions(String language,

                                                                String script,

                                                                String country,

                                                                String variant) {

         LocaleExtensions extensions = null;

         // Special cases for backward compatibility support

         if (LocaleUtils.caseIgnoreMatch(language, "ja")

                 && script.length() == 0

                 && LocaleUtils.caseIgnoreMatch(country, "jp")

                 && "JP".equals(variant)) {

             // ja_JP_JP -> u-ca-japanese (calendar = japanese)

             extensions = LocaleExtensions.CALENDAR_JAPANESE;

         } else if (LocaleUtils.caseIgnoreMatch(language, "th")

                 && script.length() == 0

                 && LocaleUtils.caseIgnoreMatch(country, "th")

                 && "TH".equals(variant)) {

             // th_TH_TH -> u-nu-thai (numbersystem = thai)

             extensions = LocaleExtensions.NUMBER_THAI;

         }

         return extensions;

     }

     /**

      * Obtains a localized locale names from a LocaleNameProvider

      * implementation.

      */

     private static class LocaleNameGetter

         implements LocaleServiceProviderPool.LocalizedObjectGetter<LocaleNameProvider, String> {

         private static final LocaleNameGetter INSTANCE = new LocaleNameGetter();

         public String getObject(LocaleNameProvider localeNameProvider,

                                 Locale locale,

                                 String key,

                                 Object... params) {

             assert params.length == 2;

             int type = (Integer)params[0];

             String code = (String)params[1];

             switch(type) {

             case DISPLAY_LANGUAGE:

                 return localeNameProvider.getDisplayLanguage(code, locale);

             case DISPLAY_COUNTRY:

                 return localeNameProvider.getDisplayCountry(code, locale);

             case DISPLAY_VARIANT:

                 return localeNameProvider.getDisplayVariant(code, locale);

             case DISPLAY_SCRIPT:

                 return localeNameProvider.getDisplayScript(code, locale);

             default:

                 assert false; // shouldn't happen

             }

             return null;

         }

     }

     /**

      * Enum for locale categories.  These locale categories are used to get/set

      * the default locale for the specific functionality represented by the

      * category.

      *

      * @see #getDefault(Locale.Category)

      * @see #setDefault(Locale.Category, Locale)

      * @since 1.7

      */

     public enum Category {

         /**

          * Category used to represent the default locale for

          * displaying user interfaces.

          */

         DISPLAY("user.language.display",

                 "user.script.display",

                 "user.country.display",

                 "user.variant.display"),

         /**

          * Category used to represent the default locale for

          * formatting dates, numbers, and/or currencies.

          */

         FORMAT("user.language.format",

                "user.script.format",

                "user.country.format",

                "user.variant.format");

         Category(String languageKey, String scriptKey, String countryKey, String variantKey) {

             this.languageKey = languageKey;

             this.scriptKey = scriptKey;

             this.countryKey = countryKey;

             this.variantKey = variantKey;

         }

         final String languageKey;

         final String scriptKey;

         final String countryKey;

         final String variantKey;

     }

     /**

      * <code>Builder</code> is used to build instances of <code>Locale</code>

      * from values configured by the setters.  Unlike the <code>Locale</code>

      * constructors, the <code>Builder</code> checks if a value configured by a

      * setter satisfies the syntax requirements defined by the <code>Locale</code>

      * class.  A <code>Locale</code> object created by a <code>Builder</code> is

      * well-formed and can be transformed to a well-formed IETF BCP 47 language tag

      * without losing information.

      *

      * <p><b>Note:</b> The <code>Locale</code> class does not provide any

      * syntactic restrictions on variant, while BCP 47 requires each variant

      * subtag to be 5 to 8 alphanumerics or a single numeric followed by 3

      * alphanumerics.  The method <code>setVariant</code> throws

      * <code>IllformedLocaleException</code> for a variant that does not satisfy

      * this restriction. If it is necessary to support such a variant, use a

      * Locale constructor.  However, keep in mind that a <code>Locale</code>

      * object created this way might lose the variant information when

      * transformed to a BCP 47 language tag.

      *

      * <p>The following example shows how to create a <code>Locale</code> object

      * with the <code>Builder</code>.

      * <blockquote>

      * <pre>

      *     Locale aLocale = new Builder().setLanguage("sr").setScript("Latn").setRegion("RS").build();

      * </pre>

      * </blockquote>

      *

      * <p>Builders can be reused; <code>clear()</code> resets all

      * fields to their default values.

      *

      * @see Locale#forLanguageTag

      * @since 1.7

      */

     public static final class Builder {

         private final InternalLocaleBuilder localeBuilder;

         /**

          * Constructs an empty Builder. The default value of all

          * fields, extensions, and private use information is the

          * empty string.

          */

         public Builder() {

             localeBuilder = new InternalLocaleBuilder();

         }

         /**

          * Resets the <code>Builder</code> to match the provided

          * <code>locale</code>.  Existing state is discarded.

          *

          * <p>All fields of the locale must be well-formed, see {@link Locale}.

          *

          * <p>Locales with any ill-formed fields cause

          * <code>IllformedLocaleException</code> to be thrown, except for the

          * following three cases which are accepted for compatibility

          * reasons:<ul>

          * <li>Locale("ja", "JP", "JP") is treated as "ja-JP-u-ca-japanese"

          * <li>Locale("th", "TH", "TH") is treated as "th-TH-u-nu-thai"

          * <li>Locale("no", "NO", "NY") is treated as "nn-NO"</ul>

          *

          * @param locale the locale

          * @return This builder.

          * @throws IllformedLocaleException if <code>locale</code> has

          * any ill-formed fields.

          * @throws NullPointerException if <code>locale</code> is null.

          */

         public Builder setLocale(Locale locale) {

             try {

                 localeBuilder.setLocale(locale.baseLocale, locale.localeExtensions);

             } catch (LocaleSyntaxException e) {

                 throw new IllformedLocaleException(e.getMessage(), e.getErrorIndex());

             }

             return this;

         }

         /**

          * Resets the Builder to match the provided IETF BCP 47

          * language tag.  Discards the existing state.  Null and the

          * empty string cause the builder to be reset, like {@link

          * #clear}.  Grandfathered tags (see {@link

          * Locale#forLanguageTag}) are converted to their canonical

          * form before being processed.  Otherwise, the language tag

          * must be well-formed (see {@link Locale}) or an exception is

          * thrown (unlike <code>Locale.forLanguageTag</code>, which

          * just discards ill-formed and following portions of the

          * tag).

          *

          * @param languageTag the language tag

          * @return This builder.

          * @throws IllformedLocaleException if <code>languageTag</code> is ill-formed

          * @see Locale#forLanguageTag(String)

          */

         public Builder setLanguageTag(String languageTag) {

             ParseStatus sts = new ParseStatus();

             LanguageTag tag = LanguageTag.parse(languageTag, sts);

             if (sts.isError()) {

                 throw new IllformedLocaleException(sts.getErrorMessage(), sts.getErrorIndex());

             }

             localeBuilder.setLanguageTag(tag);

             return this;

         }

         /**

          * Sets the language.  If <code>language</code> is the empty string or

          * null, the language in this <code>Builder</code> is removed.  Otherwise,

          * the language must be <a href="./Locale.html#def_language">well-formed</a>

          * or an exception is thrown.

          *

          * <p>The typical language value is a two or three-letter language

          * code as defined in ISO639.

          *

          * @param language the language

          * @return This builder.

          * @throws IllformedLocaleException if <code>language</code> is ill-formed

          */

         public Builder setLanguage(String language) {

             try {

                 localeBuilder.setLanguage(language);

             } catch (LocaleSyntaxException e) {

                 throw new IllformedLocaleException(e.getMessage(), e.getErrorIndex());

             }

             return this;

         }

         /**

          * Sets the script. If <code>script</code> is null or the empty string,

          * the script in this <code>Builder</code> is removed.

          * Otherwise, the script must be <a href="./Locale.html#def_script">well-formed</a> or an

          * exception is thrown.

          *

          * <p>The typical script value is a four-letter script code as defined by ISO 15924.

          *

          * @param script the script

          * @return This builder.

          * @throws IllformedLocaleException if <code>script</code> is ill-formed

          */

         public Builder setScript(String script) {

             try {

                 localeBuilder.setScript(script);

             } catch (LocaleSyntaxException e) {

                 throw new IllformedLocaleException(e.getMessage(), e.getErrorIndex());

             }

             return this;

         }

         /**

          * Sets the region.  If region is null or the empty string, the region

          * in this <code>Builder</code> is removed.  Otherwise,

          * the region must be <a href="./Locale.html#def_region">well-formed</a> or an

          * exception is thrown.

          *

          * <p>The typical region value is a two-letter ISO 3166 code or a

          * three-digit UN M.49 area code.

          *

          * <p>The country value in the <code>Locale</code> created by the

          * <code>Builder</code> is always normalized to upper case.

          *

          * @param region the region

          * @return This builder.

          * @throws IllformedLocaleException if <code>region</code> is ill-formed

          */

         public Builder setRegion(String region) {

             try {

                 localeBuilder.setRegion(region);

             } catch (LocaleSyntaxException e) {

                 throw new IllformedLocaleException(e.getMessage(), e.getErrorIndex());

             }

             return this;

         }

         /**

          * Sets the variant.  If variant is null or the empty string, the

          * variant in this <code>Builder</code> is removed.  Otherwise, it

          * must consist of one or more <a href="./Locale.html#def_variant">well-formed</a>

          * subtags, or an exception is thrown.

          *

          * <p><b>Note:</b> This method checks if <code>variant</code>

          * satisfies the IETF BCP 47 variant subtag's syntax requirements,

          * and normalizes the value to lowercase letters.  However,

          * the <code>Locale</code> class does not impose any syntactic

          * restriction on variant, and the variant value in

          * <code>Locale</code> is case sensitive.  To set such a variant,

          * use a Locale constructor.

          *

          * @param variant the variant

          * @return This builder.

          * @throws IllformedLocaleException if <code>variant</code> is ill-formed

          */

         public Builder setVariant(String variant) {

             try {

                 localeBuilder.setVariant(variant);

             } catch (LocaleSyntaxException e) {

                 throw new IllformedLocaleException(e.getMessage(), e.getErrorIndex());

             }

             return this;

         }

         /**

          * Sets the extension for the given key. If the value is null or the

          * empty string, the extension is removed.  Otherwise, the extension

          * must be <a href="./Locale.html#def_extensions">well-formed</a> or an exception

          * is thrown.

          *

          * <p><b>Note:</b> The key {@link Locale#UNICODE_LOCALE_EXTENSION

          * UNICODE_LOCALE_EXTENSION} ('u') is used for the Unicode locale extension.

          * Setting a value for this key replaces any existing Unicode locale key/type

          * pairs with those defined in the extension.

          *

          * <p><b>Note:</b> The key {@link Locale#PRIVATE_USE_EXTENSION

          * PRIVATE_USE_EXTENSION} ('x') is used for the private use code. To be

          * well-formed, the value for this key needs only to have subtags of one to

          * eight alphanumeric characters, not two to eight as in the general case.

          *

          * @param key the extension key

          * @param value the extension value

          * @return This builder.

          * @throws IllformedLocaleException if <code>key</code> is illegal

          * or <code>value</code> is ill-formed

          * @see #setUnicodeLocaleKeyword(String, String)

          */

         public Builder setExtension(char key, String value) {

             try {

                 localeBuilder.setExtension(key, value);

             } catch (LocaleSyntaxException e) {

                 throw new IllformedLocaleException(e.getMessage(), e.getErrorIndex());

             }

             return this;

         }

         /**

          * Sets the Unicode locale keyword type for the given key.  If the type

          * is null, the Unicode keyword is removed.  Otherwise, the key must be

          * non-null and both key and type must be <a

          * href="./Locale.html#def_locale_extension">well-formed</a> or an exception

          * is thrown.

          *

          * <p>Keys and types are converted to lower case.

          *

          * <p><b>Note</b>:Setting the 'u' extension via {@link #setExtension}

          * replaces all Unicode locale keywords with those defined in the

          * extension.

          *

          * @param key the Unicode locale key

          * @param type the Unicode locale type

          * @return This builder.

          * @throws IllformedLocaleException if <code>key</code> or <code>type</code>

          * is ill-formed

          * @throws NullPointerException if <code>key</code> is null

          * @see #setExtension(char, String)

          */

         public Builder setUnicodeLocaleKeyword(String key, String type) {

             try {

                 localeBuilder.setUnicodeLocaleKeyword(key, type);

             } catch (LocaleSyntaxException e) {

                 throw new IllformedLocaleException(e.getMessage(), e.getErrorIndex());

             }

             return this;

         }

         /**

          * Adds a unicode locale attribute, if not already present, otherwise

          * has no effect.  The attribute must not be null and must be <a

          * href="./Locale.html#def_locale_extension">well-formed</a> or an exception

          * is thrown.

          *

          * @param attribute the attribute

          * @return This builder.

          * @throws NullPointerException if <code>attribute</code> is null

          * @throws IllformedLocaleException if <code>attribute</code> is ill-formed

          * @see #setExtension(char, String)

          */

         public Builder addUnicodeLocaleAttribute(String attribute) {

             try {

                 localeBuilder.addUnicodeLocaleAttribute(attribute);

             } catch (LocaleSyntaxException e) {

                 throw new IllformedLocaleException(e.getMessage(), e.getErrorIndex());

             }

             return this;

         }

         /**

          * Removes a unicode locale attribute, if present, otherwise has no

          * effect.  The attribute must not be null and must be <a

          * href="./Locale.html#def_locale_extension">well-formed</a> or an exception

          * is thrown.

          *

          * <p>Attribute comparision for removal is case-insensitive.

          *

          * @param attribute the attribute

          * @return This builder.

          * @throws NullPointerException if <code>attribute</code> is null

          * @throws IllformedLocaleException if <code>attribute</code> is ill-formed

          * @see #setExtension(char, String)

          */

         public Builder removeUnicodeLocaleAttribute(String attribute) {

             try {

                 localeBuilder.removeUnicodeLocaleAttribute(attribute);

             } catch (LocaleSyntaxException e) {

                 throw new IllformedLocaleException(e.getMessage(), e.getErrorIndex());

             }

             return this;

         }

         /**

          * Resets the builder to its initial, empty state.

          *

          * @return This builder.

          */

         public Builder clear() {

             localeBuilder.clear();

             return this;

         }

         /**

          * Resets the extensions to their initial, empty state.

          * Language, script, region and variant are unchanged.

          *

          * @return This builder.

          * @see #setExtension(char, String)

          */

         public Builder clearExtensions() {

             localeBuilder.clearExtensions();

             return this;

         }

         /**

          * Returns an instance of <code>Locale</code> created from the fields set

          * on this builder.

          *

          * <p>This applies the conversions listed in {@link Locale#forLanguageTag}

          * when constructing a Locale. (Grandfathered tags are handled in

          * {@link #setLanguageTag}.)

          *

          * @return A Locale.

          */

         public Locale build() {

             BaseLocale baseloc = localeBuilder.getBaseLocale();

             LocaleExtensions extensions = localeBuilder.getLocaleExtensions();

             if (extensions == null && baseloc.getVariant().length() > 0) {

                 extensions = getCompatibilityExtensions(baseloc.getLanguage(), baseloc.getScript(),

                         baseloc.getRegion(), baseloc.getVariant());

             }

             return Locale.getInstance(baseloc, extensions);

         }

     }

 }