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 * Copyright (c) 2005, 2012, 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

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package sun.util.locale.provider;

import java.util.ArrayList;

import java.util.Collections;

import java.util.HashSet;

import java.util.IllformedLocaleException;

import java.util.List;

import java.util.Locale;

import java.util.Locale.Builder;

import java.util.ResourceBundle.Control;

import java.util.Set;

import java.util.concurrent.ConcurrentHashMap;

import java.util.concurrent.ConcurrentMap;

import java.util.spi.LocaleServiceProvider;

import sun.util.logging.PlatformLogger;

/**

 * An instance of this class holds a set of the third party implementations of a particular

 * locale sensitive service, such as {@link java.util.spi.LocaleNameProvider}.

 *

 * @author Naoto Sato

 * @author Masayoshi Okutsu

 */

public final class LocaleServiceProviderPool {

    /**

     * A Map that holds singleton instances of this class.  Each instance holds a

     * set of provider implementations of a particular locale sensitive service.

     */

    private static ConcurrentMap<Class<? extends LocaleServiceProvider>, LocaleServiceProviderPool> poolOfPools =

        new ConcurrentHashMap<>();

    /**

     * A Map containing locale service providers that implement the

     * specified provider SPI, keyed by a LocaleProviderAdapter.Type

     */

    private ConcurrentMap<LocaleProviderAdapter.Type, LocaleServiceProvider> providers =

        new ConcurrentHashMap<>();

    /**

     * A Map that retains Locale->provider mapping

     */

    private ConcurrentMap<Locale, List<LocaleProviderAdapter.Type>> providersCache =

        new ConcurrentHashMap<>();

    /**

     * Available locales for this locale sensitive service.  This also contains

     * JRE's available locales

     */

    private Set<Locale> availableLocales = null;

    /**

     * Provider class

     */

    private Class<? extends LocaleServiceProvider> providerClass;

    /**

     * Array of all Locale Sensitive SPI classes.

     *

     * We know "spiClasses" contains classes that extends LocaleServiceProvider,

     * but generic array creation is not allowed, thus the "unchecked" warning

     * is suppressed here.

     */

    @SuppressWarnings("unchecked")

    static final Class<LocaleServiceProvider>[] spiClasses =

                (Class<LocaleServiceProvider>[]) new Class<?>[] {

        java.text.spi.BreakIteratorProvider.class,

        java.text.spi.CollatorProvider.class,

        java.text.spi.DateFormatProvider.class,

        java.text.spi.DateFormatSymbolsProvider.class,

        java.text.spi.DecimalFormatSymbolsProvider.class,

        java.text.spi.NumberFormatProvider.class,

        java.util.spi.CurrencyNameProvider.class,

        java.util.spi.LocaleNameProvider.class,

        java.util.spi.TimeZoneNameProvider.class,

        java.util.spi.CalendarDataProvider.class

    };

    /**

     * A factory method that returns a singleton instance

     */

    public static LocaleServiceProviderPool getPool(Class<? extends LocaleServiceProvider> providerClass) {

        LocaleServiceProviderPool pool = poolOfPools.get(providerClass);

        if (pool == null) {

            LocaleServiceProviderPool newPool =

                new LocaleServiceProviderPool(providerClass);

            pool = poolOfPools.putIfAbsent(providerClass, newPool);

            if (pool == null) {

                pool = newPool;

            }

        }

        return pool;

    }

    /**

     * The sole constructor.

     *

     * @param c class of the locale sensitive service

     */

    private LocaleServiceProviderPool (final Class<? extends LocaleServiceProvider> c) {

        providerClass = c;

        // Add the JRE Locale Data Adapter implementation.

        providers.putIfAbsent(LocaleProviderAdapter.Type.JRE,

            LocaleProviderAdapter.forJRE().getLocaleServiceProvider(c));

        // Add the SPI Locale Data Adapter implementation.

        LocaleProviderAdapter lda = LocaleProviderAdapter.forType(LocaleProviderAdapter.Type.SPI);

        LocaleServiceProvider provider = lda.getLocaleServiceProvider(c);

        if (provider != null) {

            providers.putIfAbsent(LocaleProviderAdapter.Type.SPI, provider);

        }

        // Add the CLDR Locale Data Adapter implementation, if needed.

        lda =  LocaleProviderAdapter.forType(LocaleProviderAdapter.Type.CLDR);

        if (lda != null) {

            provider = lda.getLocaleServiceProvider(c);

            if (provider != null) {

                providers.putIfAbsent(LocaleProviderAdapter.Type.CLDR, provider);

            }

        }

        // Add the Host Locale Data Adapter implementation, if needed.

        lda =  LocaleProviderAdapter.forType(LocaleProviderAdapter.Type.HOST);

        if (lda != null) {

            provider = lda.getLocaleServiceProvider(c);

            if (provider != null) {

                providers.putIfAbsent(LocaleProviderAdapter.Type.HOST, provider);

            }

        }

    }

    static void config(Class<? extends Object> caller, String message) {

        PlatformLogger logger = PlatformLogger.getLogger(caller.getCanonicalName());

        logger.config(message);

    }

    /**

     * Lazy loaded set of available locales.

     * Loading all locales is a very long operation.

     */

    private static class AllAvailableLocales {

        /**

         * Available locales for all locale sensitive services.

         * This also contains JRE's available locales

         */

        static final Locale[] allAvailableLocales;

        static {

            Set<Locale> all = new HashSet<>();

            for (Class<? extends LocaleServiceProvider> c : spiClasses) {

                LocaleServiceProviderPool pool =

                    LocaleServiceProviderPool.getPool(c);

                all.addAll(pool.getAvailableLocaleList());

            }

            allAvailableLocales = all.toArray(new Locale[0]);

        }

        // No instantiation

        private AllAvailableLocales() {

        }

    }

    /**

     * Returns an array of available locales for all the provider classes.

     * This array is a merged array of all the locales that are provided by each

     * provider, including the JRE.

     *

     * @return an array of the available locales for all provider classes

     */

    public static Locale[] getAllAvailableLocales() {

        return AllAvailableLocales.allAvailableLocales.clone();

    }

    /**

     * Returns an array of available locales.  This array is a

     * merged array of all the locales that are provided by each

     * provider, including the JRE.

     *

     * @return an array of the available locales

     */

    public Locale[] getAvailableLocales() {

        Set<Locale> locList = getAvailableLocaleList();

        Locale[] tmp = new Locale[locList.size()];

        locList.toArray(tmp);

        return tmp;

    }

    private synchronized Set<Locale> getAvailableLocaleList() {

        if (availableLocales == null) {

            availableLocales = new HashSet<>();

            for (LocaleServiceProvider lsp : providers.values()) {

                Locale[] locales = lsp.getAvailableLocales();

                for (Locale locale: locales) {

                    availableLocales.add(getLookupLocale(locale));

                }

            }

            // Remove Locale.ROOT for the compatibility.

            availableLocales.remove(Locale.ROOT);

        }

        return availableLocales;

    }

    /**

     * Returns whether any provider for this locale sensitive

     * service is available or not, excluding JRE's one.

     *

     * @return true if any provider (other than JRE) is available

     */

    boolean hasProviders() {

        return providers.size() != 1 ||

               providers.get(LocaleProviderAdapter.Type.JRE) == null;

    }

    /**

     * Returns the provider's localized object for the specified

     * locale.

     *

     * @param getter an object on which getObject() method

     *     is called to obtain the provider's instance.

     * @param locale the given locale that is used as the starting one

     * @param params provider specific parameters

     * @return provider's instance, or null.

     */

    public <P extends LocaleServiceProvider, S> S getLocalizedObject(LocalizedObjectGetter<P, S> getter,

                                     Locale locale,

                                     Object... params) {

        return getLocalizedObjectImpl(getter, locale, true, null, params);

    }

    /**

     * Returns the provider's localized name for the specified

     * locale.

     *

     * @param getter an object on which getObject() method

     *     is called to obtain the provider's instance.

     * @param locale the given locale that is used as the starting one

     * @param key the key string for name providers

     * @param params provider specific parameters

     * @return provider's instance, or null.

     */

    public <P extends LocaleServiceProvider, S> S getLocalizedObject(LocalizedObjectGetter<P, S> getter,

                                     Locale locale,

                                     String key,

                                     Object... params) {

        return getLocalizedObjectImpl(getter, locale, false, key, params);

    }

    @SuppressWarnings("unchecked")

    private <P extends LocaleServiceProvider, S> S getLocalizedObjectImpl(LocalizedObjectGetter<P, S> getter,

                                     Locale locale,

                                     boolean isObjectProvider,

                                     String key,

                                     Object... params) {

        if (locale == null) {

            throw new NullPointerException();

        }

        // Check whether JRE is the sole locale data provider or not,

        // and directly call it if it is.

        if (!hasProviders()) {

            return getter.getObject(

                (P)providers.get(LocaleProviderAdapter.Type.JRE),

                locale, key, params);

        }

        List<Locale> lookupLocales = getLookupLocales(locale);

        Set<Locale> available = getAvailableLocaleList();

        for (Locale current : lookupLocales) {

            if (available.contains(current)) {

                S providersObj;

                for (LocaleProviderAdapter.Type type: findProviders(current)) {

                    LocaleServiceProvider lsp = providers.get(type);

                    if (providersObj != null) {

                        return providersObj;

                    } else if (isObjectProvider) {

                        config(LocaleServiceProviderPool.class,

                            "A locale sensitive service provider returned null for a localized objects,  which should not happen.  provider: "

                                + lsp + " locale: " + locale);

                    }

                }

            }

        }

        // not found.

        return null;

    }

    /**

     * Returns the list of locale service provider instances that support

     * the specified locale.

     *

     * @param locale the given locale

     * @return the list of locale data adapter types

     */

    private List<LocaleProviderAdapter.Type> findProviders(Locale locale) {

        List<LocaleProviderAdapter.Type> providersList = providersCache.get(locale);

        if (providersList == null) {

            for (LocaleProviderAdapter.Type type : LocaleProviderAdapter.getAdapterPreference()) {

                LocaleServiceProvider lsp = providers.get(type);

                if (lsp != null) {

                    if (lsp.isSupportedLocale(locale)) {

                        if (providersList == null) {

                            providersList = new ArrayList<>(2);

                        }

                        providersList.add(type);

                    }

                }

            }

            if (providersList == null) {

                providersList = NULL_LIST;

            }

            List<LocaleProviderAdapter.Type> val = providersCache.putIfAbsent(locale, providersList);

            if (val != null) {

                providersList = val;

            }

        }

            return providersList;

        }

    /**

     * Returns a list of candidate locales for service look up.

     * @param locale the input locale

     * @return the list of candidate locales for the given locale

     */

    private static List<Locale> getLookupLocales(Locale locale) {

        // Note: We currently use the default implementation of

        // ResourceBundle.Control.getCandidateLocales. The result

        // returned by getCandidateLocales are already normalized

        // (no extensions) for service look up.

        List<Locale> lookupLocales = Control.getNoFallbackControl(Control.FORMAT_DEFAULT)

                                            .getCandidateLocales("", locale);

        return lookupLocales;

    }

    /**

     * Returns an instance of Locale used for service look up.

     * The result Locale has no extensions except for ja_JP_JP

     * and th_TH_TH

     *

     * @param locale the locale

     * @return the locale used for service look up

     */

    static Locale getLookupLocale(Locale locale) {

        Locale lookupLocale = locale;

        if (locale.hasExtensions()

                && !locale.equals(JRELocaleConstants.JA_JP_JP)

                && !locale.equals(JRELocaleConstants.TH_TH_TH)) {

            // remove extensions

            Builder locbld = new Builder();

            try {

                locbld.setLocale(locale);

                locbld.clearExtensions();

                lookupLocale = locbld.build();

            } catch (IllformedLocaleException e) {

                // A Locale with non-empty extensions

                // should have well-formed fields except

                // for ja_JP_JP and th_TH_TH. Therefore,

                // it should never enter in this catch clause.

                config(LocaleServiceProviderPool.class,

                       "A locale(" + locale + ") has non-empty extensions, but has illformed fields.");

                // Fallback - script field will be lost.

                lookupLocale = new Locale(locale.getLanguage(), locale.getCountry(), locale.getVariant());

            }

        }

        return lookupLocale;

    }

    /**

     * A dummy locale service provider list that indicates there is no

     * provider available

     */

    private static List<LocaleProviderAdapter.Type> NULL_LIST =

        Collections.emptyList();

    /**

     * An interface to get a localized object for each locale sensitive

     * service class.

     */

    public interface LocalizedObjectGetter<P extends LocaleServiceProvider, S> {

        /**

         * Returns an object from the provider

         *

         * @param lsp the provider

         * @param locale the locale

         * @param key key string to localize, or null if the provider is not

         *     a name provider

         * @param params provider specific params

         * @return localized object from the provider

         */

        public S getObject(P lsp,

                           Locale locale,

                           String key,

                           Object... params);

    }

}