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

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

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

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 * 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).

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/*

 * This file is available under and governed by the GNU General Public

 * License version 2 only, as published by the Free Software Foundation.

 * However, the following notice accompanied the original version of this

 * file:

 *

 * Copyright (c) 2009-2012, Stephen Colebourne & Michael Nascimento Santos

 *

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 *

 *  * Redistributions of source code must retain the above copyright notice,

 *    this list of conditions and the following disclaimer.

 *

 *  * Redistributions in binary form must reproduce the above copyright notice,

 *    this list of conditions and the following disclaimer in the documentation

 *    and/or other materials provided with the distribution.

 *

 *  * Neither the name of JSR-310 nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR

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 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

package java.time.format;

import java.text.SimpleDateFormat;

import java.util.Locale;

import java.util.concurrent.ConcurrentHashMap;

import java.util.concurrent.ConcurrentMap;

/**

 * A provider to obtain date-time formatters for a style.

 * <p>

 *

 * <h3>Specification for implementors</h3>

 * This implementation is based on extraction of data from a {@link SimpleDateFormat}.

 * This class is immutable and thread-safe.

 * This Implementations caches the returned formatters.

 *

 * @since 1.8

 */

final class DateTimeFormatStyleProvider {

    // TODO: Better implementation based on CLDR

    /** Cache of formatters. */

    private static final ConcurrentMap<String, Object> FORMATTER_CACHE = new ConcurrentHashMap<>(16, 0.75f, 2);

    private DateTimeFormatStyleProvider() {}

    /**

     * Gets an Instance of the provider of format styles.

     *

     * @return the provider, not null

     */

    static DateTimeFormatStyleProvider getInstance() {

        return new DateTimeFormatStyleProvider();

    }

    /**

     * Gets a localized date, time or date-time formatter.

     * <p>

     * The formatter will be the most appropriate to use for the date and time style in the locale.

     * For example, some locales will use the month name while others will use the number.

     *

     * @param dateStyle  the date formatter style to obtain, null to obtain a time formatter

     * @param timeStyle  the time formatter style to obtain, null to obtain a date formatter

     * @param chrono  the chronology to use, not null

     * @param locale  the locale to use, not null

     * @return the date-time formatter, not null

     * @throws IllegalArgumentException if both format styles are null or if the locale is not recognized

     */

    public DateTimeFormatter getFormatter(

        if (dateStyle == null && timeStyle == null) {

            throw new IllegalArgumentException("Date and Time style must not both be null");

        }

        String key = chrono.getId() + '|' + locale.toString() + '|' + dateStyle + timeStyle;

        Object cached = FORMATTER_CACHE.get(key);

        if (cached != null) {

            return (DateTimeFormatter) cached;

        }

    }

    /**

     */

    private int convertStyle(FormatStyle style) {

        return style.ordinal();  // indices happen to align

    }

}