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package java.util.spi;

import java.util.Calendar;

import java.util.Locale;

import java.util.Map;

/**

 * An abstract class for service providers that provide localized string

 * representations (display names) of {@code Calendar} field values.

 *

 * <p><a id="calendartypes"><b>Calendar Types</b></a>

 *

 * <p>Calendar types are used to specify calendar systems for which the {@link

 * #getDisplayName(String, int, int, int, Locale) getDisplayName} and {@link

 * #getDisplayNames(String, int, int, Locale) getDisplayNames} methods provide

 * calendar field value names. See {@link Calendar#getCalendarType()} for details.

 *

 * <p><b>Calendar Fields</b>

 *

 * <p>Calendar fields are specified with the constants defined in {@link

 * Calendar}. The following are calendar-common fields and their values to be

 * supported for each calendar system.

 *

 * <table class="striped">

 * <caption style="display:none">Field values</caption>

 * <thead>

 *   <tr>

 *     <th scope="col">Field</th>

 *     <th scope="col">Value</th>

 *     <th scope="col">Description</th>

 *   </tr>

 * </thead>

 * <tbody>

 *   <tr>

 *     <th scope="row" style="vertical-align:top">{@link Calendar#MONTH}</th>

 *     <td style="vertical-align:top">{@link Calendar#JANUARY} to {@link Calendar#UNDECIMBER}</td>

 *     <td>Month numbering is 0-based (e.g., 0 - January, ..., 11 -

 *         December). Some calendar systems have 13 months. Month

 *         names need to be supported in both the formatting and

 *         stand-alone forms if required by the supported locales. If there's

 *         no distinction in the two forms, the same names should be returned

 *         in both of the forms.</td>

 *   </tr>

 *   <tr>

 *     <th scope="row" style="vertical-align:top">{@link Calendar#DAY_OF_WEEK}</th>

 *     <td style="vertical-align:top">{@link Calendar#SUNDAY} to {@link Calendar#SATURDAY}</td>

 *     <td>Day-of-week numbering is 1-based starting from Sunday (i.e., 1 - Sunday,

 *         ..., 7 - Saturday).</td>

 *   </tr>

 *   <tr>

 *     <th scope="row" style="vertical-align:top">{@link Calendar#AM_PM}</th>

 *     <td style="vertical-align:top">{@link Calendar#AM} to {@link Calendar#PM}</td>

 *     <td>0 - AM, 1 - PM</td>

 *   </tr>

 * </tbody>

 * </table>

 *

 * <p style="margin-top:20px">The following are calendar-specific fields and their values to be supported.

 *

 * <table class="plain">

 * <caption style="display:none">Calendar type and field values</caption>

 * <thead>

 *   <tr>

 *     <th scope="col">Calendar Type</th>

 *     <th scope="col">Field</th>

 *     <th scope="col">Value</th>

 *     <th scope="col">Description</th>

 *   </tr>

 * </thead>

 * <tbody>

 *   <tr>

 *     <th scope="row"rowspan="2" style="font-weight:normal; text-align:left; vertical-align:top">{@code "gregory"}</th>

 *     <th scope="row" rowspan="2" style="font-weight:normal; text-align:left; vertical-align:top">{@link Calendar#ERA}</th>

 *     <th scope="row" style="font-weight:normal">0</th>

 *     <td>{@link java.util.GregorianCalendar#BC} (BCE)</td>

 *   </tr>

 *   <tr>

 *     <th scope="row" style="font-weight:normal">1</th>

 *     <td>{@link java.util.GregorianCalendar#AD} (CE)</td>

 *   </tr>

 *   <tr>

 *     <th scope="row" rowspan="2" style="font-weight:normal; text-align:left; vertical-align:top">{@code "buddhist"}</th>

 *     <th scope="row" rowspan="2" style="font-weight:normal; text-align:left; vertical-align:top">{@link Calendar#ERA}</th>

 *     <th scope="row" style="font-weight:normal">0</th>

 *     <td>BC (BCE)</td>

 *   </tr>

 *   <tr>

 *     <th scope="row" style="font-weight:normal">1</th>

 *     <td>B.E. (Buddhist Era)</td>

 *   </tr>

 *   <tr>

 *     <th scope="row" style="font-weight:normal">0</th>

 *     <td>Seireki (Before Meiji)</td>

 *   </tr>

 *   <tr>

 *     <th scope="row" style="font-weight:normal">1</th>

 *     <td>Meiji</td>

 *   </tr>

 *   <tr>

 *     <th scope="row" style="font-weight:normal">2</th>

 *     <td>Taisho</td>

 *   </tr>

 *   <tr>

 *     <th scope="row" style="font-weight:normal">3</th>

 *     <td>Showa</td>

 *   </tr>

 *   <tr>

 *     <th scope="row" style="font-weight:normal">4</th>

 *   </tr>

 *   <tr>

 *     <th scope="row" style="font-weight:normal; text-align:left; vertical-align:top">{@link Calendar#YEAR}</th>

 *     <th scope="row" style="font-weight:normal">1</th>

 *     <td>the first year in each era. It should be returned when a long

 *     style ({@link Calendar#LONG_FORMAT} or {@link Calendar#LONG_STANDALONE}) is

 *     specified. See also the <a href="../../text/SimpleDateFormat.html#year">

 *     Year representation in {@code SimpleDateFormat}</a>.</td>

 *   </tr>

 *   <tr>

 *     <th scope="row" rowspan="2" style="font-weight:normal; text-align:left; vertical-align:top">{@code "roc"}</th>

 *     <th scope="row" rowspan="2" style="font-weight:normal; text-align:left; vertical-align:top">{@link Calendar#ERA}</th>

 *     <th scope="row" style="font-weight:normal">0</th>

 *     <td>Before R.O.C.</td>

 *   </tr>

 *   <tr>

 *     <th scope="row" style="font-weight:normal">1</th>

 *     <td>R.O.C.</td>

 *   </tr>

 *   <tr>

 *     <th scope="row" rowspan="2" style="font-weight:normal; text-align:left; vertical-align:top">{@code "islamic"}</th>

 *     <th scope="row" rowspan="2" style="font-weight:normal; text-align:left; vertical-align:top">{@link Calendar#ERA}</th>

 *     <th scope="row" style="font-weight:normal">0</th>

 *     <td>Before AH</td>

 *   </tr>

 *   <tr>

 *     <th scope="row" style="font-weight:normal">1</th>

 *     <td>Anno Hijrah (AH)</td>

 *   </tr>

 * </tbody>

 * </table>

 *

 * <p>Calendar field value names for {@code "gregory"} must be consistent with

 * the date-time symbols provided by {@link java.text.spi.DateFormatSymbolsProvider}.

 *

 * <p>Time zone names are supported by {@link TimeZoneNameProvider}.

 *

 * @author Masayoshi Okutsu

 * @since 1.8

 * @see CalendarDataProvider

 * @see Locale#getUnicodeLocaleType(String)

 */

public abstract class CalendarNameProvider extends LocaleServiceProvider {

    /**

     * Sole constructor. (For invocation by subclass constructors, typically

     * implicit.)

     */

    protected CalendarNameProvider() {

    }

    /**

     * Returns the string representation (display name) of the calendar

     * <code>field value</code> in the given <code>style</code> and

     * <code>locale</code>.  If no string representation is

     * applicable, <code>null</code> is returned.

     *

     * <p>{@code field} is a {@code Calendar} field index, such as {@link

     * Calendar#MONTH}. The time zone fields, {@link Calendar#ZONE_OFFSET} and

     * {@link Calendar#DST_OFFSET}, are <em>not</em> supported by this

     * method. {@code null} must be returned if any time zone fields are

     * specified.

     *

     * <p>{@code value} is the numeric representation of the {@code field} value.

     * For example, if {@code field} is {@link Calendar#DAY_OF_WEEK}, the valid

     * values are {@link Calendar#SUNDAY} to {@link Calendar#SATURDAY}

     * (inclusive).

     *

     * <p>{@code style} gives the style of the string representation. It is one

     * of {@link Calendar#SHORT_FORMAT} ({@link Calendar#SHORT SHORT}),

     * {@link Calendar#SHORT_STANDALONE}, {@link Calendar#LONG_FORMAT}

     * ({@link Calendar#LONG LONG}), {@link Calendar#LONG_STANDALONE},

     * {@link Calendar#NARROW_FORMAT}, or {@link Calendar#NARROW_STANDALONE}.

     *

     * <p>For example, the following call will return {@code "Sunday"}.

     * <pre>

     * getDisplayName("gregory", Calendar.DAY_OF_WEEK, Calendar.SUNDAY,

     *                Calendar.LONG_STANDALONE, Locale.ENGLISH);

     * </pre>

     *

     * @param calendarType

     *              the calendar type. (Any calendar type given by {@code locale}

     *              is ignored.)

     * @param field

     *              the {@code Calendar} field index,

     *              such as {@link Calendar#DAY_OF_WEEK}

     * @param value

     *              the value of the {@code Calendar field},

     *              such as {@link Calendar#MONDAY}

     * @param style

     *              the string representation style: one of {@link

     *              Calendar#SHORT_FORMAT} ({@link Calendar#SHORT SHORT}),

     *              {@link Calendar#SHORT_STANDALONE}, {@link

     *              Calendar#LONG_FORMAT} ({@link Calendar#LONG LONG}),

     *              {@link Calendar#LONG_STANDALONE},

     *              {@link Calendar#NARROW_FORMAT},

     *              or {@link Calendar#NARROW_STANDALONE}

     * @param locale

     *              the desired locale

     * @return the string representation of the {@code field value}, or {@code

     *         null} if the string representation is not applicable or

     *         the given calendar type is unknown

     * @throws IllegalArgumentException

     *         if {@code field} or {@code style} is invalid

     * @throws NullPointerException if {@code locale} is {@code null}

     * @see TimeZoneNameProvider

     * @see java.util.Calendar#get(int)

     * @see java.util.Calendar#getDisplayName(int, int, Locale)

     */

    public abstract String getDisplayName(String calendarType,

                                          int field, int value,

                                          int style, Locale locale);

    /**

     * Returns a {@code Map} containing all string representations (display

     * names) of the {@code Calendar} {@code field} in the given {@code style}

     * and {@code locale} and their corresponding field values.

     *

     * <p>{@code field} is a {@code Calendar} field index, such as {@link

     * Calendar#MONTH}. The time zone fields, {@link Calendar#ZONE_OFFSET} and

     * {@link Calendar#DST_OFFSET}, are <em>not</em> supported by this

     * method. {@code null} must be returned if any time zone fields are specified.

     *

     * <p>{@code style} gives the style of the string representation. It must be

     * one of {@link Calendar#ALL_STYLES}, {@link Calendar#SHORT_FORMAT} ({@link

     * Calendar#SHORT SHORT}), {@link Calendar#SHORT_STANDALONE}, {@link

     * Calendar#LONG_FORMAT} ({@link Calendar#LONG LONG}), {@link

     * Calendar#LONG_STANDALONE}, {@link Calendar#NARROW_FORMAT}, or

     * {@link Calendar#NARROW_STANDALONE}. Note that narrow names may

     * not be unique due to use of single characters, such as "S" for Sunday

     * and Saturday, and that no narrow names are included in that case.

     *

     * <p>For example, the following call will return a {@code Map} containing

     * {@code "January"} to {@link Calendar#JANUARY}, {@code "Jan"} to {@link

     * Calendar#JANUARY}, {@code "February"} to {@link Calendar#FEBRUARY},

     * {@code "Feb"} to {@link Calendar#FEBRUARY}, and so on.

     * <pre>

     * getDisplayNames("gregory", Calendar.MONTH, Calendar.ALL_STYLES, Locale.ENGLISH);

     * </pre>

     *

     * @param calendarType

     *              the calendar type. (Any calendar type given by {@code locale}

     *              is ignored.)

     * @param field

     *              the calendar field for which the display names are returned

     * @param style

     *              the style applied to the display names; one of

     *              {@link Calendar#ALL_STYLES}, {@link Calendar#SHORT_FORMAT}

     *              ({@link Calendar#SHORT SHORT}), {@link

     *              Calendar#SHORT_STANDALONE}, {@link Calendar#LONG_FORMAT}

     *              ({@link Calendar#LONG LONG}), {@link Calendar#LONG_STANDALONE},

     *              {@link Calendar#NARROW_FORMAT},

     *              or {@link Calendar#NARROW_STANDALONE}

     * @param locale

     *              the desired locale

     * @return a {@code Map} containing all display names of {@code field} in

     *         {@code style} and {@code locale} and their {@code field} values,

     *         or {@code null} if no display names are defined for {@code field}

     * @throws NullPointerException

     *         if {@code locale} is {@code null}

     * @see Calendar#getDisplayNames(int, int, Locale)

     */

    public abstract Map<String, Integer> getDisplayNames(String calendarType,

                                                         int field, int style,

                                                         Locale locale);

}