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    1   /*
    2    * Copyright (c) 1996, 2010, Oracle and/or its affiliates. All rights reserved.
    3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
    4    *
    5    * This code is free software; you can redistribute it and/or modify it
    6    * under the terms of the GNU General Public License version 2 only, as
    7    * published by the Free Software Foundation.  Oracle designates this
    8    * particular file as subject to the "Classpath" exception as provided
    9    * by Oracle in the LICENSE file that accompanied this code.
   10    *
   11    * This code is distributed in the hope that it will be useful, but WITHOUT
   12    * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   13    * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   14    * version 2 for more details (a copy is included in the LICENSE file that
   15    * accompanied this code).
   16    *
   17    * You should have received a copy of the GNU General Public License version
   18    * 2 along with this work; if not, write to the Free Software Foundation,
   19    * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   20    *
   21    * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   22    * or visit www.oracle.com if you need additional information or have any
   23    * questions.
   24    */
   25   
   26   /*
   27    * (C) Copyright Taligent, Inc. 1996 - All Rights Reserved
   28    * (C) Copyright IBM Corp. 1996 - All Rights Reserved
   29    *
   30    *   The original version of this source code and documentation is copyrighted
   31    * and owned by Taligent, Inc., a wholly-owned subsidiary of IBM. These
   32    * materials are provided under terms of a License Agreement between Taligent
   33    * and Sun. This technology is protected by multiple US and International
   34    * patents. This notice and attribution to Taligent may not be removed.
   35    *   Taligent is a registered trademark of Taligent, Inc.
   36    *
   37    */
   38   
   39   package java.text;
   40   
   41   import java.io.InvalidObjectException;
   42   import java.text.spi.DateFormatProvider;
   43   import java.util.Calendar;
   44   import java.util.Date;
   45   import java.util.GregorianCalendar;
   46   import java.util.HashMap;
   47   import java.util.Locale;
   48   import java.util.Map;
   49   import java.util.MissingResourceException;
   50   import java.util.ResourceBundle;
   51   import java.util.TimeZone;
   52   import java.util.spi.LocaleServiceProvider;
   53   import sun.util.LocaleServiceProviderPool;
   54   
   55   /**
   56    * {@code DateFormat} is an abstract class for date/time formatting subclasses which
   57    * formats and parses dates or time in a language-independent manner.
   58    * The date/time formatting subclass, such as {@link SimpleDateFormat}, allows for
   59    * formatting (i.e., date -> text), parsing (text -> date), and
   60    * normalization.  The date is represented as a <code>Date</code> object or
   61    * as the milliseconds since January 1, 1970, 00:00:00 GMT.
   62    *
   63    * <p>{@code DateFormat} provides many class methods for obtaining default date/time
   64    * formatters based on the default or a given locale and a number of formatting
   65    * styles. The formatting styles include {@link #FULL}, {@link #LONG}, {@link #MEDIUM}, and {@link #SHORT}. More
   66    * detail and examples of using these styles are provided in the method
   67    * descriptions.
   68    *
   69    * <p>{@code DateFormat} helps you to format and parse dates for any locale.
   70    * Your code can be completely independent of the locale conventions for
   71    * months, days of the week, or even the calendar format: lunar vs. solar.
   72    *
   73    * <p>To format a date for the current Locale, use one of the
   74    * static factory methods:
   75    * <pre>
   76    *  myString = DateFormat.getDateInstance().format(myDate);
   77    * </pre>
   78    * <p>If you are formatting multiple dates, it is
   79    * more efficient to get the format and use it multiple times so that
   80    * the system doesn't have to fetch the information about the local
   81    * language and country conventions multiple times.
   82    * <pre>
   83    *  DateFormat df = DateFormat.getDateInstance();
   84    *  for (int i = 0; i < myDate.length; ++i) {
   85    *    output.println(df.format(myDate[i]) + "; ");
   86    *  }
   87    * </pre>
   88    * <p>To format a date for a different Locale, specify it in the
   89    * call to {@link #getDateInstance(int, Locale) getDateInstance()}.
   90    * <pre>
   91    *  DateFormat df = DateFormat.getDateInstance(DateFormat.LONG, Locale.FRANCE);
   92    * </pre>
   93    * <p>You can use a DateFormat to parse also.
   94    * <pre>
   95    *  myDate = df.parse(myString);
   96    * </pre>
   97    * <p>Use {@code getDateInstance} to get the normal date format for that country.
   98    * There are other static factory methods available.
   99    * Use {@code getTimeInstance} to get the time format for that country.
  100    * Use {@code getDateTimeInstance} to get a date and time format. You can pass in
  101    * different options to these factory methods to control the length of the
  102    * result; from {@link #SHORT} to {@link #MEDIUM} to {@link #LONG} to {@link #FULL}. The exact result depends
  103    * on the locale, but generally:
  104    * <ul><li>{@link #SHORT} is completely numeric, such as {@code 12.13.52} or {@code 3:30pm}
  105    * <li>{@link #MEDIUM} is longer, such as {@code Jan 12, 1952}
  106    * <li>{@link #LONG} is longer, such as {@code January 12, 1952} or {@code 3:30:32pm}
  107    * <li>{@link #FULL} is pretty completely specified, such as
  108    * {@code Tuesday, April 12, 1952 AD or 3:30:42pm PST}.
  109    * </ul>
  110    *
  111    * <p>You can also set the time zone on the format if you wish.
  112    * If you want even more control over the format or parsing,
  113    * (or want to give your users more control),
  114    * you can try casting the {@code DateFormat} you get from the factory methods
  115    * to a {@link SimpleDateFormat}. This will work for the majority
  116    * of countries; just remember to put it in a {@code try} block in case you
  117    * encounter an unusual one.
  118    *
  119    * <p>You can also use forms of the parse and format methods with
  120    * {@link ParsePosition} and {@link FieldPosition} to
  121    * allow you to
  122    * <ul><li>progressively parse through pieces of a string.
  123    * <li>align any particular field, or find out where it is for selection
  124    * on the screen.
  125    * </ul>
  126    *
  127    * <h4><a name="synchronization">Synchronization</a></h4>
  128    *
  129    * <p>
  130    * Date formats are not synchronized.
  131    * It is recommended to create separate format instances for each thread.
  132    * If multiple threads access a format concurrently, it must be synchronized
  133    * externally.
  134    *
  135    * @see          Format
  136    * @see          NumberFormat
  137    * @see          SimpleDateFormat
  138    * @see          java.util.Calendar
  139    * @see          java.util.GregorianCalendar
  140    * @see          java.util.TimeZone
  141    * @author       Mark Davis, Chen-Lieh Huang, Alan Liu
  142    */
  143   public abstract class DateFormat extends Format {
  144   
  145       /**
  146        * The {@link Calendar} instance used for calculating the date-time fields
  147        * and the instant of time. This field is used for both formatting and
  148        * parsing.
  149        *
  150        * <p>Subclasses should initialize this field to a {@link Calendar}
  151        * appropriate for the {@link Locale} associated with this
  152        * <code>DateFormat</code>.
  153        * @serial
  154        */
  155       protected Calendar calendar;
  156   
  157       /**
  158        * The number formatter that <code>DateFormat</code> uses to format numbers
  159        * in dates and times.  Subclasses should initialize this to a number format
  160        * appropriate for the locale associated with this <code>DateFormat</code>.
  161        * @serial
  162        */
  163       protected NumberFormat numberFormat;
  164   
  165       /**
  166        * Useful constant for ERA field alignment.
  167        * Used in FieldPosition of date/time formatting.
  168        */
  169       public final static int ERA_FIELD = 0;
  170       /**
  171        * Useful constant for YEAR field alignment.
  172        * Used in FieldPosition of date/time formatting.
  173        */
  174       public final static int YEAR_FIELD = 1;
  175       /**
  176        * Useful constant for MONTH field alignment.
  177        * Used in FieldPosition of date/time formatting.
  178        */
  179       public final static int MONTH_FIELD = 2;
  180       /**
  181        * Useful constant for DATE field alignment.
  182        * Used in FieldPosition of date/time formatting.
  183        */
  184       public final static int DATE_FIELD = 3;
  185       /**
  186        * Useful constant for one-based HOUR_OF_DAY field alignment.
  187        * Used in FieldPosition of date/time formatting.
  188        * HOUR_OF_DAY1_FIELD is used for the one-based 24-hour clock.
  189        * For example, 23:59 + 01:00 results in 24:59.
  190        */
  191       public final static int HOUR_OF_DAY1_FIELD = 4;
  192       /**
  193        * Useful constant for zero-based HOUR_OF_DAY field alignment.
  194        * Used in FieldPosition of date/time formatting.
  195        * HOUR_OF_DAY0_FIELD is used for the zero-based 24-hour clock.
  196        * For example, 23:59 + 01:00 results in 00:59.
  197        */
  198       public final static int HOUR_OF_DAY0_FIELD = 5;
  199       /**
  200        * Useful constant for MINUTE field alignment.
  201        * Used in FieldPosition of date/time formatting.
  202        */
  203       public final static int MINUTE_FIELD = 6;
  204       /**
  205        * Useful constant for SECOND field alignment.
  206        * Used in FieldPosition of date/time formatting.
  207        */
  208       public final static int SECOND_FIELD = 7;
  209       /**
  210        * Useful constant for MILLISECOND field alignment.
  211        * Used in FieldPosition of date/time formatting.
  212        */
  213       public final static int MILLISECOND_FIELD = 8;
  214       /**
  215        * Useful constant for DAY_OF_WEEK field alignment.
  216        * Used in FieldPosition of date/time formatting.
  217        */
  218       public final static int DAY_OF_WEEK_FIELD = 9;
  219       /**
  220        * Useful constant for DAY_OF_YEAR field alignment.
  221        * Used in FieldPosition of date/time formatting.
  222        */
  223       public final static int DAY_OF_YEAR_FIELD = 10;
  224       /**
  225        * Useful constant for DAY_OF_WEEK_IN_MONTH field alignment.
  226        * Used in FieldPosition of date/time formatting.
  227        */
  228       public final static int DAY_OF_WEEK_IN_MONTH_FIELD = 11;
  229       /**
  230        * Useful constant for WEEK_OF_YEAR field alignment.
  231        * Used in FieldPosition of date/time formatting.
  232        */
  233       public final static int WEEK_OF_YEAR_FIELD = 12;
  234       /**
  235        * Useful constant for WEEK_OF_MONTH field alignment.
  236        * Used in FieldPosition of date/time formatting.
  237        */
  238       public final static int WEEK_OF_MONTH_FIELD = 13;
  239       /**
  240        * Useful constant for AM_PM field alignment.
  241        * Used in FieldPosition of date/time formatting.
  242        */
  243       public final static int AM_PM_FIELD = 14;
  244       /**
  245        * Useful constant for one-based HOUR field alignment.
  246        * Used in FieldPosition of date/time formatting.
  247        * HOUR1_FIELD is used for the one-based 12-hour clock.
  248        * For example, 11:30 PM + 1 hour results in 12:30 AM.
  249        */
  250       public final static int HOUR1_FIELD = 15;
  251       /**
  252        * Useful constant for zero-based HOUR field alignment.
  253        * Used in FieldPosition of date/time formatting.
  254        * HOUR0_FIELD is used for the zero-based 12-hour clock.
  255        * For example, 11:30 PM + 1 hour results in 00:30 AM.
  256        */
  257       public final static int HOUR0_FIELD = 16;
  258       /**
  259        * Useful constant for TIMEZONE field alignment.
  260        * Used in FieldPosition of date/time formatting.
  261        */
  262       public final static int TIMEZONE_FIELD = 17;
  263   
  264       // Proclaim serial compatibility with 1.1 FCS
  265       private static final long serialVersionUID = 7218322306649953788L;
  266   
  267       /**
  268        * Overrides Format.
  269        * Formats a time object into a time string. Examples of time objects
  270        * are a time value expressed in milliseconds and a Date object.
  271        * @param obj must be a Number or a Date.
  272        * @param toAppendTo the string buffer for the returning time string.
  273        * @return the string buffer passed in as toAppendTo, with formatted text appended.
  274        * @param fieldPosition keeps track of the position of the field
  275        * within the returned string.
  276        * On input: an alignment field,
  277        * if desired. On output: the offsets of the alignment field. For
  278        * example, given a time text "1996.07.10 AD at 15:08:56 PDT",
  279        * if the given fieldPosition is DateFormat.YEAR_FIELD, the
  280        * begin index and end index of fieldPosition will be set to
  281        * 0 and 4, respectively.
  282        * Notice that if the same time field appears
  283        * more than once in a pattern, the fieldPosition will be set for the first
  284        * occurrence of that time field. For instance, formatting a Date to
  285        * the time string "1 PM PDT (Pacific Daylight Time)" using the pattern
  286        * "h a z (zzzz)" and the alignment field DateFormat.TIMEZONE_FIELD,
  287        * the begin index and end index of fieldPosition will be set to
  288        * 5 and 8, respectively, for the first occurrence of the timezone
  289        * pattern character 'z'.
  290        * @see java.text.Format
  291        */
  292       public final StringBuffer format(Object obj, StringBuffer toAppendTo,
  293                                        FieldPosition fieldPosition)
  294       {
  295           if (obj instanceof Date)
  296               return format( (Date)obj, toAppendTo, fieldPosition );
  297           else if (obj instanceof Number)
  298               return format( new Date(((Number)obj).longValue()),
  299                             toAppendTo, fieldPosition );
  300           else
  301               throw new IllegalArgumentException("Cannot format given Object as a Date");
  302       }
  303   
  304       /**
  305        * Formats a Date into a date/time string.
  306        * @param date a Date to be formatted into a date/time string.
  307        * @param toAppendTo the string buffer for the returning date/time string.
  308        * @param fieldPosition keeps track of the position of the field
  309        * within the returned string.
  310        * On input: an alignment field,
  311        * if desired. On output: the offsets of the alignment field. For
  312        * example, given a time text "1996.07.10 AD at 15:08:56 PDT",
  313        * if the given fieldPosition is DateFormat.YEAR_FIELD, the
  314        * begin index and end index of fieldPosition will be set to
  315        * 0 and 4, respectively.
  316        * Notice that if the same time field appears
  317        * more than once in a pattern, the fieldPosition will be set for the first
  318        * occurrence of that time field. For instance, formatting a Date to
  319        * the time string "1 PM PDT (Pacific Daylight Time)" using the pattern
  320        * "h a z (zzzz)" and the alignment field DateFormat.TIMEZONE_FIELD,
  321        * the begin index and end index of fieldPosition will be set to
  322        * 5 and 8, respectively, for the first occurrence of the timezone
  323        * pattern character 'z'.
  324        * @return the string buffer passed in as toAppendTo, with formatted text appended.
  325        */
  326       public abstract StringBuffer format(Date date, StringBuffer toAppendTo,
  327                                           FieldPosition fieldPosition);
  328   
  329       /**
  330        * Formats a Date into a date/time string.
  331        * @param date the time value to be formatted into a time string.
  332        * @return the formatted time string.
  333        */
  334       public final String format(Date date)
  335       {
  336           return format(date, new StringBuffer(),
  337                         DontCareFieldPosition.INSTANCE).toString();
  338       }
  339   
  340       /**
  341        * Parses text from the beginning of the given string to produce a date.
  342        * The method may not use the entire text of the given string.
  343        * <p>
  344        * See the {@link #parse(String, ParsePosition)} method for more information
  345        * on date parsing.
  346        *
  347        * @param source A <code>String</code> whose beginning should be parsed.
  348        * @return A <code>Date</code> parsed from the string.
  349        * @exception ParseException if the beginning of the specified string
  350        *            cannot be parsed.
  351        */
  352       public Date parse(String source) throws ParseException
  353       {
  354           ParsePosition pos = new ParsePosition(0);
  355           Date result = parse(source, pos);
  356           if (pos.index == 0)
  357               throw new ParseException("Unparseable date: \"" + source + "\"" ,
  358                   pos.errorIndex);
  359           return result;
  360       }
  361   
  362       /**
  363        * Parse a date/time string according to the given parse position.  For
  364        * example, a time text {@code "07/10/96 4:5 PM, PDT"} will be parsed into a {@code Date}
  365        * that is equivalent to {@code Date(837039900000L)}.
  366        *
  367        * <p> By default, parsing is lenient: If the input is not in the form used
  368        * by this object's format method but can still be parsed as a date, then
  369        * the parse succeeds.  Clients may insist on strict adherence to the
  370        * format by calling {@link #setLenient(boolean) setLenient(false)}.
  371        *
  372        * <p>This parsing operation uses the {@link #calendar} to produce
  373        * a {@code Date}. As a result, the {@code calendar}'s date-time
  374        * fields and the {@code TimeZone} value may have been
  375        * overwritten, depending on subclass implementations. Any {@code
  376        * TimeZone} value that has previously been set by a call to
  377        * {@link #setTimeZone(java.util.TimeZone) setTimeZone} may need
  378        * to be restored for further operations.
  379        *
  380        * @param source  The date/time string to be parsed
  381        *
  382        * @param pos   On input, the position at which to start parsing; on
  383        *              output, the position at which parsing terminated, or the
  384        *              start position if the parse failed.
  385        *
  386        * @return      A {@code Date}, or {@code null} if the input could not be parsed
  387        */
  388       public abstract Date parse(String source, ParsePosition pos);
  389   
  390       /**
  391        * Parses text from a string to produce a <code>Date</code>.
  392        * <p>
  393        * The method attempts to parse text starting at the index given by
  394        * <code>pos</code>.
  395        * If parsing succeeds, then the index of <code>pos</code> is updated
  396        * to the index after the last character used (parsing does not necessarily
  397        * use all characters up to the end of the string), and the parsed
  398        * date is returned. The updated <code>pos</code> can be used to
  399        * indicate the starting point for the next call to this method.
  400        * If an error occurs, then the index of <code>pos</code> is not
  401        * changed, the error index of <code>pos</code> is set to the index of
  402        * the character where the error occurred, and null is returned.
  403        * <p>
  404        * See the {@link #parse(String, ParsePosition)} method for more information
  405        * on date parsing.
  406        *
  407        * @param source A <code>String</code>, part of which should be parsed.
  408        * @param pos A <code>ParsePosition</code> object with index and error
  409        *            index information as described above.
  410        * @return A <code>Date</code> parsed from the string. In case of
  411        *         error, returns null.
  412        * @exception NullPointerException if <code>pos</code> is null.
  413        */
  414       public Object parseObject(String source, ParsePosition pos) {
  415           return parse(source, pos);
  416       }
  417   
  418       /**
  419        * Constant for full style pattern.
  420        */
  421       public static final int FULL = 0;
  422       /**
  423        * Constant for long style pattern.
  424        */
  425       public static final int LONG = 1;
  426       /**
  427        * Constant for medium style pattern.
  428        */
  429       public static final int MEDIUM = 2;
  430       /**
  431        * Constant for short style pattern.
  432        */
  433       public static final int SHORT = 3;
  434       /**
  435        * Constant for default style pattern.  Its value is MEDIUM.
  436        */
  437       public static final int DEFAULT = MEDIUM;
  438   
  439       /**
  440        * Gets the time formatter with the default formatting style
  441        * for the default locale.
  442        * @return a time formatter.
  443        */
  444       public final static DateFormat getTimeInstance()
  445       {
  446           return get(DEFAULT, 0, 1, Locale.getDefault(Locale.Category.FORMAT));
  447       }
  448   
  449       /**
  450        * Gets the time formatter with the given formatting style
  451        * for the default locale.
  452        * @param style the given formatting style. For example,
  453        * SHORT for "h:mm a" in the US locale.
  454        * @return a time formatter.
  455        */
  456       public final static DateFormat getTimeInstance(int style)
  457       {
  458           return get(style, 0, 1, Locale.getDefault(Locale.Category.FORMAT));
  459       }
  460   
  461       /**
  462        * Gets the time formatter with the given formatting style
  463        * for the given locale.
  464        * @param style the given formatting style. For example,
  465        * SHORT for "h:mm a" in the US locale.
  466        * @param aLocale the given locale.
  467        * @return a time formatter.
  468        */
  469       public final static DateFormat getTimeInstance(int style,
  470                                                    Locale aLocale)
  471       {
  472           return get(style, 0, 1, aLocale);
  473       }
  474   
  475       /**
  476        * Gets the date formatter with the default formatting style
  477        * for the default locale.
  478        * @return a date formatter.
  479        */
  480       public final static DateFormat getDateInstance()
  481       {
  482           return get(0, DEFAULT, 2, Locale.getDefault(Locale.Category.FORMAT));
  483       }
  484   
  485       /**
  486        * Gets the date formatter with the given formatting style
  487        * for the default locale.
  488        * @param style the given formatting style. For example,
  489        * SHORT for "M/d/yy" in the US locale.
  490        * @return a date formatter.
  491        */
  492       public final static DateFormat getDateInstance(int style)
  493       {
  494           return get(0, style, 2, Locale.getDefault(Locale.Category.FORMAT));
  495       }
  496   
  497       /**
  498        * Gets the date formatter with the given formatting style
  499        * for the given locale.
  500        * @param style the given formatting style. For example,
  501        * SHORT for "M/d/yy" in the US locale.
  502        * @param aLocale the given locale.
  503        * @return a date formatter.
  504        */
  505       public final static DateFormat getDateInstance(int style,
  506                                                    Locale aLocale)
  507       {
  508           return get(0, style, 2, aLocale);
  509       }
  510   
  511       /**
  512        * Gets the date/time formatter with the default formatting style
  513        * for the default locale.
  514        * @return a date/time formatter.
  515        */
  516       public final static DateFormat getDateTimeInstance()
  517       {
  518           return get(DEFAULT, DEFAULT, 3, Locale.getDefault(Locale.Category.FORMAT));
  519       }
  520   
  521       /**
  522        * Gets the date/time formatter with the given date and time
  523        * formatting styles for the default locale.
  524        * @param dateStyle the given date formatting style. For example,
  525        * SHORT for "M/d/yy" in the US locale.
  526        * @param timeStyle the given time formatting style. For example,
  527        * SHORT for "h:mm a" in the US locale.
  528        * @return a date/time formatter.
  529        */
  530       public final static DateFormat getDateTimeInstance(int dateStyle,
  531                                                          int timeStyle)
  532       {
  533           return get(timeStyle, dateStyle, 3, Locale.getDefault(Locale.Category.FORMAT));
  534       }
  535   
  536       /**
  537        * Gets the date/time formatter with the given formatting styles
  538        * for the given locale.
  539        * @param dateStyle the given date formatting style.
  540        * @param timeStyle the given time formatting style.
  541        * @param aLocale the given locale.
  542        * @return a date/time formatter.
  543        */
  544       public final static DateFormat
  545           getDateTimeInstance(int dateStyle, int timeStyle, Locale aLocale)
  546       {
  547           return get(timeStyle, dateStyle, 3, aLocale);
  548       }
  549   
  550       /**
  551        * Get a default date/time formatter that uses the SHORT style for both the
  552        * date and the time.
  553        */
  554       public final static DateFormat getInstance() {
  555           return getDateTimeInstance(SHORT, SHORT);
  556       }
  557   
  558       /**
  559        * Returns an array of all locales for which the
  560        * <code>get*Instance</code> methods of this class can return
  561        * localized instances.
  562        * The returned array represents the union of locales supported by the Java
  563        * runtime and by installed
  564        * {@link java.text.spi.DateFormatProvider DateFormatProvider} implementations.
  565        * It must contain at least a <code>Locale</code> instance equal to
  566        * {@link java.util.Locale#US Locale.US}.
  567        *
  568        * @return An array of locales for which localized
  569        *         <code>DateFormat</code> instances are available.
  570        */
  571       public static Locale[] getAvailableLocales()
  572       {
  573           LocaleServiceProviderPool pool =
  574               LocaleServiceProviderPool.getPool(DateFormatProvider.class);
  575           return pool.getAvailableLocales();
  576       }
  577   
  578       /**
  579        * Set the calendar to be used by this date format.  Initially, the default
  580        * calendar for the specified or default locale is used.
  581        *
  582        * <p>Any {@link java.util.TimeZone TimeZone} and {@linkplain
  583        * #isLenient() leniency} values that have previously been set are
  584        * overwritten by {@code newCalendar}'s values.
  585        *
  586        * @param newCalendar the new {@code Calendar} to be used by the date format
  587        */
  588       public void setCalendar(Calendar newCalendar)
  589       {
  590           this.calendar = newCalendar;
  591       }
  592   
  593       /**
  594        * Gets the calendar associated with this date/time formatter.
  595        *
  596        * @return the calendar associated with this date/time formatter.
  597        */
  598       public Calendar getCalendar()
  599       {
  600           return calendar;
  601       }
  602   
  603       /**
  604        * Allows you to set the number formatter.
  605        * @param newNumberFormat the given new NumberFormat.
  606        */
  607       public void setNumberFormat(NumberFormat newNumberFormat)
  608       {
  609           this.numberFormat = newNumberFormat;
  610       }
  611   
  612       /**
  613        * Gets the number formatter which this date/time formatter uses to
  614        * format and parse a time.
  615        * @return the number formatter which this date/time formatter uses.
  616        */
  617       public NumberFormat getNumberFormat()
  618       {
  619           return numberFormat;
  620       }
  621   
  622       /**
  623        * Sets the time zone for the calendar of this {@code DateFormat} object.
  624        * This method is equivalent to the following call.
  625        * <blockquote><pre>
  626        *  getCalendar().setTimeZone(zone)
  627        * </pre></blockquote>
  628        *
  629        * <p>The {@code TimeZone} set by this method is overwritten by a
  630        * {@link #setCalendar(java.util.Calendar) setCalendar} call.
  631        *
  632        * <p>The {@code TimeZone} set by this method may be overwritten as
  633        * a result of a call to the parse method.
  634        *
  635        * @param zone the given new time zone.
  636        */
  637       public void setTimeZone(TimeZone zone)
  638       {
  639           calendar.setTimeZone(zone);
  640       }
  641   
  642       /**
  643        * Gets the time zone.
  644        * This method is equivalent to the following call.
  645        * <blockquote><pre>
  646        *  getCalendar().getTimeZone()
  647        * </pre></blockquote>
  648        *
  649        * @return the time zone associated with the calendar of DateFormat.
  650        */
  651       public TimeZone getTimeZone()
  652       {
  653           return calendar.getTimeZone();
  654       }
  655   
  656       /**
  657        * Specify whether or not date/time parsing is to be lenient.  With
  658        * lenient parsing, the parser may use heuristics to interpret inputs that
  659        * do not precisely match this object's format.  With strict parsing,
  660        * inputs must match this object's format.
  661        *
  662        * <p>This method is equivalent to the following call.
  663        * <blockquote><pre>
  664        *  getCalendar().setLenient(lenient)
  665        * </pre></blockquote>
  666        *
  667        * <p>This leniency value is overwritten by a call to {@link
  668        * #setCalendar(java.util.Calendar) setCalendar()}.
  669        *
  670        * @param lenient when {@code true}, parsing is lenient
  671        * @see java.util.Calendar#setLenient(boolean)
  672        */
  673       public void setLenient(boolean lenient)
  674       {
  675           calendar.setLenient(lenient);
  676       }
  677   
  678       /**
  679        * Tell whether date/time parsing is to be lenient.
  680        * This method is equivalent to the following call.
  681        * <blockquote><pre>
  682        *  getCalendar().isLenient()
  683        * </pre></blockquote>
  684        *
  685        * @return {@code true} if the {@link #calendar} is lenient;
  686        *         {@code false} otherwise.
  687        * @see java.util.Calendar#isLenient()
  688        */
  689       public boolean isLenient()
  690       {
  691           return calendar.isLenient();
  692       }
  693   
  694       /**
  695        * Overrides hashCode
  696        */
  697       public int hashCode() {
  698           return numberFormat.hashCode();
  699           // just enough fields for a reasonable distribution
  700       }
  701   
  702       /**
  703        * Overrides equals
  704        */
  705       public boolean equals(Object obj) {
  706           if (this == obj) return true;
  707           if (obj == null || getClass() != obj.getClass()) return false;
  708           DateFormat other = (DateFormat) obj;
  709           return (// calendar.equivalentTo(other.calendar) // THIS API DOESN'T EXIST YET!
  710                   calendar.getFirstDayOfWeek() == other.calendar.getFirstDayOfWeek() &&
  711                   calendar.getMinimalDaysInFirstWeek() == other.calendar.getMinimalDaysInFirstWeek() &&
  712                   calendar.isLenient() == other.calendar.isLenient() &&
  713                   calendar.getTimeZone().equals(other.calendar.getTimeZone()) &&
  714                   numberFormat.equals(other.numberFormat));
  715       }
  716   
  717       /**
  718        * Overrides Cloneable
  719        */
  720       public Object clone()
  721       {
  722           DateFormat other = (DateFormat) super.clone();
  723           other.calendar = (Calendar) calendar.clone();
  724           other.numberFormat = (NumberFormat) numberFormat.clone();
  725           return other;
  726       }
  727   
  728       /**
  729        * Creates a DateFormat with the given time and/or date style in the given
  730        * locale.
  731        * @param timeStyle a value from 0 to 3 indicating the time format,
  732        * ignored if flags is 2
  733        * @param dateStyle a value from 0 to 3 indicating the time format,
  734        * ignored if flags is 1
  735        * @param flags either 1 for a time format, 2 for a date format,
  736        * or 3 for a date/time format
  737        * @param loc the locale for the format
  738        */
  739       private static DateFormat get(int timeStyle, int dateStyle,
  740                                     int flags, Locale loc) {
  741           if ((flags & 1) != 0) {
  742               if (timeStyle < 0 || timeStyle > 3) {
  743                   throw new IllegalArgumentException("Illegal time style " + timeStyle);
  744               }
  745           } else {
  746               timeStyle = -1;
  747           }
  748           if ((flags & 2) != 0) {
  749               if (dateStyle < 0 || dateStyle > 3) {
  750                   throw new IllegalArgumentException("Illegal date style " + dateStyle);
  751               }
  752           } else {
  753               dateStyle = -1;
  754           }
  755           try {
  756               // Check whether a provider can provide an implementation that's closer
  757               // to the requested locale than what the Java runtime itself can provide.
  758               LocaleServiceProviderPool pool =
  759                   LocaleServiceProviderPool.getPool(DateFormatProvider.class);
  760               if (pool.hasProviders()) {
  761                   DateFormat providersInstance = pool.getLocalizedObject(
  762                                                       DateFormatGetter.INSTANCE,
  763                                                       loc,
  764                                                       timeStyle,
  765                                                       dateStyle,
  766                                                       flags);
  767                   if (providersInstance != null) {
  768                       return providersInstance;
  769                   }
  770               }
  771   
  772               return new SimpleDateFormat(timeStyle, dateStyle, loc);
  773           } catch (MissingResourceException e) {
  774               return new SimpleDateFormat("M/d/yy h:mm a");
  775           }
  776       }
  777   
  778       /**
  779        * Create a new date format.
  780        */
  781       protected DateFormat() {}
  782   
  783       /**
  784        * Defines constants that are used as attribute keys in the
  785        * <code>AttributedCharacterIterator</code> returned
  786        * from <code>DateFormat.formatToCharacterIterator</code> and as
  787        * field identifiers in <code>FieldPosition</code>.
  788        * <p>
  789        * The class also provides two methods to map
  790        * between its constants and the corresponding Calendar constants.
  791        *
  792        * @since 1.4
  793        * @see java.util.Calendar
  794        */
  795       public static class Field extends Format.Field {
  796   
  797           // Proclaim serial compatibility with 1.4 FCS
  798           private static final long serialVersionUID = 7441350119349544720L;
  799   
  800           // table of all instances in this class, used by readResolve
  801           private static final Map instanceMap = new HashMap(18);
  802           // Maps from Calendar constant (such as Calendar.ERA) to Field
  803           // constant (such as Field.ERA).
  804           private static final Field[] calendarToFieldMapping =
  805                                                new Field[Calendar.FIELD_COUNT];
  806   
  807           /** Calendar field. */
  808           private int calendarField;
  809   
  810           /**
  811            * Returns the <code>Field</code> constant that corresponds to
  812            * the <code>Calendar</code> constant <code>calendarField</code>.
  813            * If there is no direct mapping between the <code>Calendar</code>
  814            * constant and a <code>Field</code>, null is returned.
  815            *
  816            * @throws IllegalArgumentException if <code>calendarField</code> is
  817            *         not the value of a <code>Calendar</code> field constant.
  818            * @param calendarField Calendar field constant
  819            * @return Field instance representing calendarField.
  820            * @see java.util.Calendar
  821            */
  822           public static Field ofCalendarField(int calendarField) {
  823               if (calendarField < 0 || calendarField >=
  824                           calendarToFieldMapping.length) {
  825                   throw new IllegalArgumentException("Unknown Calendar constant "
  826                                                      + calendarField);
  827               }
  828               return calendarToFieldMapping[calendarField];
  829           }
  830   
  831           /**
  832            * Creates a <code>Field</code>.
  833            *
  834            * @param name the name of the <code>Field</code>
  835            * @param calendarField the <code>Calendar</code> constant this
  836            *        <code>Field</code> corresponds to; any value, even one
  837            *        outside the range of legal <code>Calendar</code> values may
  838            *        be used, but <code>-1</code> should be used for values
  839            *        that don't correspond to legal <code>Calendar</code> values
  840            */
  841           protected Field(String name, int calendarField) {
  842               super(name);
  843               this.calendarField = calendarField;
  844               if (this.getClass() == DateFormat.Field.class) {
  845                   instanceMap.put(name, this);
  846                   if (calendarField >= 0) {
  847                       // assert(calendarField < Calendar.FIELD_COUNT);
  848                       calendarToFieldMapping[calendarField] = this;
  849                   }
  850               }
  851           }
  852   
  853           /**
  854            * Returns the <code>Calendar</code> field associated with this
  855            * attribute. For example, if this represents the hours field of
  856            * a <code>Calendar</code>, this would return
  857            * <code>Calendar.HOUR</code>. If there is no corresponding
  858            * <code>Calendar</code> constant, this will return -1.
  859            *
  860            * @return Calendar constant for this field
  861            * @see java.util.Calendar
  862            */
  863           public int getCalendarField() {
  864               return calendarField;
  865           }
  866   
  867           /**
  868            * Resolves instances being deserialized to the predefined constants.
  869            *
  870            * @throws InvalidObjectException if the constant could not be
  871            *         resolved.
  872            * @return resolved DateFormat.Field constant
  873            */
  874           protected Object readResolve() throws InvalidObjectException {
  875               if (this.getClass() != DateFormat.Field.class) {
  876                   throw new InvalidObjectException("subclass didn't correctly implement readResolve");
  877               }
  878   
  879               Object instance = instanceMap.get(getName());
  880               if (instance != null) {
  881                   return instance;
  882               } else {
  883                   throw new InvalidObjectException("unknown attribute name");
  884               }
  885           }
  886   
  887           //
  888           // The constants
  889           //
  890   
  891           /**
  892            * Constant identifying the era field.
  893            */
  894           public final static Field ERA = new Field("era", Calendar.ERA);
  895   
  896           /**
  897            * Constant identifying the year field.
  898            */
  899           public final static Field YEAR = new Field("year", Calendar.YEAR);
  900   
  901           /**
  902            * Constant identifying the month field.
  903            */
  904           public final static Field MONTH = new Field("month", Calendar.MONTH);
  905   
  906           /**
  907            * Constant identifying the day of month field.
  908            */
  909           public final static Field DAY_OF_MONTH = new
  910                               Field("day of month", Calendar.DAY_OF_MONTH);
  911   
  912           /**
  913            * Constant identifying the hour of day field, where the legal values
  914            * are 1 to 24.
  915            */
  916           public final static Field HOUR_OF_DAY1 = new Field("hour of day 1",-1);
  917   
  918           /**
  919            * Constant identifying the hour of day field, where the legal values
  920            * are 0 to 23.
  921            */
  922           public final static Field HOUR_OF_DAY0 = new
  923                  Field("hour of day", Calendar.HOUR_OF_DAY);
  924   
  925           /**
  926            * Constant identifying the minute field.
  927            */
  928           public final static Field MINUTE =new Field("minute", Calendar.MINUTE);
  929   
  930           /**
  931            * Constant identifying the second field.
  932            */
  933           public final static Field SECOND =new Field("second", Calendar.SECOND);
  934   
  935           /**
  936            * Constant identifying the millisecond field.
  937            */
  938           public final static Field MILLISECOND = new
  939                   Field("millisecond", Calendar.MILLISECOND);
  940   
  941           /**
  942            * Constant identifying the day of week field.
  943            */
  944           public final static Field DAY_OF_WEEK = new
  945                   Field("day of week", Calendar.DAY_OF_WEEK);
  946   
  947           /**
  948            * Constant identifying the day of year field.
  949            */
  950           public final static Field DAY_OF_YEAR = new
  951                   Field("day of year", Calendar.DAY_OF_YEAR);
  952   
  953           /**
  954            * Constant identifying the day of week field.
  955            */
  956           public final static Field DAY_OF_WEEK_IN_MONTH =
  957                        new Field("day of week in month",
  958                                               Calendar.DAY_OF_WEEK_IN_MONTH);
  959   
  960           /**
  961            * Constant identifying the week of year field.
  962            */
  963           public final static Field WEEK_OF_YEAR = new
  964                 Field("week of year", Calendar.WEEK_OF_YEAR);
  965   
  966           /**
  967            * Constant identifying the week of month field.
  968            */
  969           public final static Field WEEK_OF_MONTH = new
  970               Field("week of month", Calendar.WEEK_OF_MONTH);
  971   
  972           /**
  973            * Constant identifying the time of day indicator
  974            * (e.g. "a.m." or "p.m.") field.
  975            */
  976           public final static Field AM_PM = new
  977                               Field("am pm", Calendar.AM_PM);
  978   
  979           /**
  980            * Constant identifying the hour field, where the legal values are
  981            * 1 to 12.
  982            */
  983           public final static Field HOUR1 = new Field("hour 1", -1);
  984   
  985           /**
  986            * Constant identifying the hour field, where the legal values are
  987            * 0 to 11.
  988            */
  989           public final static Field HOUR0 = new
  990                               Field("hour", Calendar.HOUR);
  991   
  992           /**
  993            * Constant identifying the time zone field.
  994            */
  995           public final static Field TIME_ZONE = new Field("time zone", -1);
  996       }
  997   
  998       /**
  999        * Obtains a DateFormat instance from a DateFormatProvider
 1000        * implementation.
 1001        */
 1002       private static class DateFormatGetter
 1003           implements LocaleServiceProviderPool.LocalizedObjectGetter<DateFormatProvider, DateFormat> {
 1004           private static final DateFormatGetter INSTANCE = new DateFormatGetter();
 1005   
 1006           public DateFormat getObject(DateFormatProvider dateFormatProvider,
 1007                                   Locale locale,
 1008                                   String key,
 1009                                   Object... params) {
 1010               assert params.length == 3;
 1011   
 1012               int timeStyle = (Integer)params[0];
 1013               int dateStyle = (Integer)params[1];
 1014               int flags = (Integer)params[2];
 1015   
 1016               switch (flags) {
 1017               case 1:
 1018                   return dateFormatProvider.getTimeInstance(timeStyle, locale);
 1019               case 2:
 1020                   return dateFormatProvider.getDateInstance(dateStyle, locale);
 1021               case 3:
 1022                   return dateFormatProvider.getDateTimeInstance(dateStyle, timeStyle, locale);
 1023               default:
 1024                   assert false : "should not happen";
 1025               }
 1026   
 1027               return null;
 1028           }
 1029       }
 1030   }

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