text: /*
   ********************************************************************************
   *   Copyright (C) 1997-2014, International Business Machines
   *   Corporation and others.  All Rights Reserved.
   ********************************************************************************
   *
   * File DATEFMT.H
   *
   * Modification History:
   *
   *   Date        Name        Description
   *   02/19/97    aliu        Converted from java.
   *   04/01/97    aliu        Added support for centuries.
   *   07/23/98    stephen     JDK 1.2 sync
   *   11/15/99    weiv        Added support for week of year/day of week formatting
   ********************************************************************************
   */
  
  #ifndef DATEFMT_H
  #define DATEFMT_H
  
  #include "unicode/utypes.h"
  
  #if !UCONFIG_NO_FORMATTING
  
  #include "unicode/udat.h"
  #include "unicode/calendar.h"
  #include "unicode/numfmt.h"
  #include "unicode/format.h"
  #include "unicode/locid.h"
  #include "unicode/enumset.h"
  #include "unicode/udisplaycontext.h"
  
  /**
   * \file
   * \brief C++ API: Abstract class for converting dates.
   */
  
  U_NAMESPACE_BEGIN
  
  class TimeZone;
  class DateTimePatternGenerator;
  
  // explicit template instantiation. see digitlst.h
  #if defined (_MSC_VER)
  template class U_I18N_API EnumSet<UDateFormatBooleanAttribute,
              0, 
              UDAT_BOOLEAN_ATTRIBUTE_COUNT>;
  #endif
  
  /**
   * DateFormat is an abstract class for a family of classes that convert dates and
   * times from their internal representations to textual form and back again in a
   * language-independent manner. Converting from the internal representation (milliseconds
   * since midnight, January 1, 1970) to text is known as "formatting," and converting
   * from text to millis is known as "parsing."  We currently define only one concrete
   * subclass of DateFormat: SimpleDateFormat, which can handle pretty much all normal
   * date formatting and parsing actions.
   * <P>
   * DateFormat helps you to format and parse dates for any locale. Your code can
   * be completely independent of the locale conventions for months, days of the
   * week, or even the calendar format: lunar vs. solar.
   * <P>
   * To format a date for the current Locale, use one of the static factory
   * methods:
   * <pre>
   * \code
   *      DateFormat* dfmt = DateFormat::createDateInstance();
   *      UDate myDate = Calendar::getNow();
   *      UnicodeString myString;
   *      myString = dfmt->format( myDate, myString );
   * \endcode
   * </pre>
   * If you are formatting multiple numbers, it is more efficient to get the
   * format and use it multiple times so that the system doesn't have to fetch the
   * information about the local language and country conventions multiple times.
   * <pre>
   * \code
   *      DateFormat* df = DateFormat::createDateInstance();
   *      UnicodeString myString;
   *      UDate myDateArr[] = { 0.0, 100000000.0, 2000000000.0 }; // test values
   *      for (int32_t i = 0; i < 3; ++i) {
   *          myString.remove();
   *          cout << df->format( myDateArr[i], myString ) << endl;
   *      }
   * \endcode
   * </pre>
   * To get specific fields of a date, you can use UFieldPosition to
   * get specific fields.
   * <pre>
   * \code
   *      DateFormat* dfmt = DateFormat::createDateInstance();
   *      FieldPosition pos(DateFormat::YEAR_FIELD);
   *      UnicodeString myString;
   *      myString = dfmt->format( myDate, myString );
   *      cout << myString << endl;
   *      cout << pos.getBeginIndex() << "," << pos. getEndIndex() << endl;
   * \endcode
   * </pre>
   * To format a date for a different Locale, specify it in the call to
   * createDateInstance().
   * <pre>
   * \code
   *       DateFormat* df =
   *           DateFormat::createDateInstance( DateFormat::SHORT, Locale::getFrance());
   * \endcode
   * </pre>
   * You can use a DateFormat to parse also.
   * <pre>
   * \code
   *       UErrorCode status = U_ZERO_ERROR;
   *       UDate myDate = df->parse(myString, status);
   * \endcode
   * </pre>
   * Use createDateInstance() to produce the normal date format for that country.
   * There are other static factory methods available. Use createTimeInstance()
   * to produce the normal time format for that country. Use createDateTimeInstance()
   * to produce a DateFormat that formats both date and time. You can pass in
   * different options to these factory methods to control the length of the
   * result; from SHORT to MEDIUM to LONG to FULL. The exact result depends on the
   * locale, but generally:
   * <ul type=round>
   *   <li>   SHORT is completely numeric, such as 12/13/52 or 3:30pm
   *   <li>   MEDIUM is longer, such as Jan 12, 1952
   *   <li>   LONG is longer, such as January 12, 1952 or 3:30:32pm
   *   <li>   FULL is pretty completely specified, such as
   *          Tuesday, April 12, 1952 AD or 3:30:42pm PST.
   * </ul>
   * You can also set the time zone on the format if you wish. If you want even
   * more control over the format or parsing, (or want to give your users more
   * control), you can try casting the DateFormat you get from the factory methods
   * to a SimpleDateFormat. This will work for the majority of countries; just
   * remember to chck getDynamicClassID() before carrying out the cast.
   * <P>
   * You can also use forms of the parse and format methods with ParsePosition and
   * FieldPosition to allow you to
   * <ul type=round>
   *   <li>   Progressively parse through pieces of a string.
   *   <li>   Align any particular field, or find out where it is for selection
   *          on the screen.
   * </ul>
   *
   * <p><em>User subclasses are not supported.</em> While clients may write
   * subclasses, such code will not necessarily work and will not be
   * guaranteed to work stably from release to release.
   */
  class U_I18N_API DateFormat : public Format {
  public:
  
      /**
       * Constants for various style patterns. These reflect the order of items in
       * the DateTimePatterns resource. There are 4 time patterns, 4 date patterns,
       * the default date-time pattern, and 4 date-time patterns. Each block of 4 values
       * in the resource occurs in the order full, long, medium, short.
       * @stable ICU 2.4
       */
      enum EStyle
      {
          kNone   = -1,
  
          kFull   = 0,
          kLong   = 1,
          kMedium = 2,
          kShort  = 3,
  
          kDateOffset   = kShort + 1,
       // kFull   + kDateOffset = 4
       // kLong   + kDateOffset = 5
       // kMedium + kDateOffset = 6
       // kShort  + kDateOffset = 7
  
          kDateTime             = 8,
       // Default DateTime
  
          kDateTimeOffset = kDateTime + 1,
       // kFull   + kDateTimeOffset = 9
       // kLong   + kDateTimeOffset = 10
       // kMedium + kDateTimeOffset = 11
       // kShort  + kDateTimeOffset = 12
  
          // relative dates
          kRelative = (1 << 7),
  
          kFullRelative = (kFull | kRelative),
  
          kLongRelative = kLong | kRelative,
  
          kMediumRelative = kMedium | kRelative,
  
          kShortRelative = kShort | kRelative,
  
  
          kDefault      = kMedium,
  
  
  
      /**
       * These constants are provided for backwards compatibility only.
       * Please use the C++ style constants defined above.
       */
          FULL        = kFull,
          LONG        = kLong,
          MEDIUM        = kMedium,
          SHORT        = kShort,
          DEFAULT        = kDefault,
          DATE_OFFSET    = kDateOffset,
          NONE        = kNone,
          DATE_TIME    = kDateTime
      };
  
      /**
       * Destructor.
       * @stable ICU 2.0
       */
      virtual ~DateFormat();
  
      /**
       * Equality operator.  Returns true if the two formats have the same behavior.
       * @stable ICU 2.0
       */
      virtual UBool operator==(const Format&) const;
  
  
      using Format::format;
  
      /**
       * Format an object to produce a string. This method handles Formattable
       * objects with a UDate type. If a the Formattable object type is not a Date,
       * then it returns a failing UErrorCode.
       *
       * @param obj       The object to format. Must be a Date.
       * @param appendTo  Output parameter to receive result.
       *                  Result is appended to existing contents.
       * @param pos       On input: an alignment field, if desired.
       *                  On output: the offsets of the alignment field.
       * @param status    Output param filled with success/failure status.
       * @return          Reference to 'appendTo' parameter.
       * @stable ICU 2.0
       */
      virtual UnicodeString& format(const Formattable& obj,
                                    UnicodeString& appendTo,
                                    FieldPosition& pos,
                                    UErrorCode& status) const;
  
      /**
       * Format an object to produce a string. This method handles Formattable
       * objects with a UDate type. If a the Formattable object type is not a Date,
       * then it returns a failing UErrorCode.
       *
       * @param obj       The object to format. Must be a Date.
       * @param appendTo  Output parameter to receive result.
       *                  Result is appended to existing contents.
       * @param posIter   On return, can be used to iterate over positions
       *                  of fields generated by this format call.  Field values
       *                  are defined in UDateFormatField.  Can be NULL.
       * @param status    Output param filled with success/failure status.
       * @return          Reference to 'appendTo' parameter.
       * @stable ICU 4.4
       */
      virtual UnicodeString& format(const Formattable& obj,
                                    UnicodeString& appendTo,
                                    FieldPositionIterator* posIter,
                                    UErrorCode& status) const;
      /**
       * Formats a date into a date/time string. This is an abstract method which
       * concrete subclasses must implement.
       * <P>
       * On input, the FieldPosition parameter may have its "field" member filled with
       * an enum value specifying a field.  On output, the FieldPosition will be filled
       * in with the text offsets for that field.
       * <P> For example, given a time text
       * "1996.07.10 AD at 15:08:56 PDT", if the given fieldPosition.field is
       * UDAT_YEAR_FIELD, the offsets fieldPosition.beginIndex and
       * statfieldPositionus.getEndIndex will be set to 0 and 4, respectively.
       * <P> Notice
       * that if the same time field appears more than once in a pattern, the status will
       * be set for the first occurence of that time field. For instance,
       * formatting a UDate to the time string "1 PM PDT (Pacific Daylight Time)"
       * using the pattern "h a z (zzzz)" and the alignment field
       * DateFormat::TIMEZONE_FIELD, the offsets fieldPosition.beginIndex and
       * fieldPosition.getEndIndex will be set to 5 and 8, respectively, for the first
       * occurence of the timezone pattern character 'z'.
       *
       * @param cal           Calendar set to the date and time to be formatted
       *                      into a date/time string.  When the calendar type is
       *                      different from the internal calendar held by this
       *                      DateFormat instance, the date and the time zone will
       *                      be inherited from the input calendar, but other calendar
       *                      field values will be calculated by the internal calendar.
       * @param appendTo      Output parameter to receive result.
       *                      Result is appended to existing contents.
       * @param fieldPosition On input: an alignment field, if desired (see examples above)
       *                      On output: the offsets of the alignment field (see examples above)
       * @return              Reference to 'appendTo' parameter.
       * @stable ICU 2.1
       */
      virtual UnicodeString& format(  Calendar& cal,
                                      UnicodeString& appendTo,
                                      FieldPosition& fieldPosition) const = 0;
  
      /**
       * Formats a date into a date/time string. Subclasses should implement this method.
       *
       * @param cal       Calendar set to the date and time to be formatted
       *                  into a date/time string.  When the calendar type is
       *                  different from the internal calendar held by this
       *                  DateFormat instance, the date and the time zone will
       *                  be inherited from the input calendar, but other calendar
       *                  field values will be calculated by the internal calendar.
       * @param appendTo  Output parameter to receive result.
       *                  Result is appended to existing contents.
       * @param posIter   On return, can be used to iterate over positions
       *                  of fields generated by this format call.  Field values
       *                  are defined in UDateFormatField.  Can be NULL.
       * @param status    error status.
       * @return          Reference to 'appendTo' parameter.
       * @stable ICU 4.4
       */
      virtual UnicodeString& format(Calendar& cal,
                                    UnicodeString& appendTo,
                                    FieldPositionIterator* posIter,
                                    UErrorCode& status) const;
      /**
       * Formats a UDate into a date/time string.
       * <P>
       * On input, the FieldPosition parameter may have its "field" member filled with
       * an enum value specifying a field.  On output, the FieldPosition will be filled
       * in with the text offsets for that field.
       * <P> For example, given a time text
       * "1996.07.10 AD at 15:08:56 PDT", if the given fieldPosition.field is
       * UDAT_YEAR_FIELD, the offsets fieldPosition.beginIndex and
       * statfieldPositionus.getEndIndex will be set to 0 and 4, respectively.
       * <P> Notice
       * that if the same time field appears more than once in a pattern, the status will
       * be set for the first occurence of that time field. For instance,
       * formatting a UDate to the time string "1 PM PDT (Pacific Daylight Time)"
       * using the pattern "h a z (zzzz)" and the alignment field
       * DateFormat::TIMEZONE_FIELD, the offsets fieldPosition.beginIndex and
       * fieldPosition.getEndIndex will be set to 5 and 8, respectively, for the first
       * occurence of the timezone pattern character 'z'.
       *
       * @param date          UDate to be formatted into a date/time string.
       * @param appendTo      Output parameter to receive result.
       *                      Result is appended to existing contents.
       * @param fieldPosition On input: an alignment field, if desired (see examples above)
       *                      On output: the offsets of the alignment field (see examples above)
       * @return              Reference to 'appendTo' parameter.
       * @stable ICU 2.0
       */
      UnicodeString& format(  UDate date,
                              UnicodeString& appendTo,
                              FieldPosition& fieldPosition) const;
  
      /**
       * Formats a UDate into a date/time string.
       *
       * @param date      UDate to be formatted into a date/time string.
       * @param appendTo  Output parameter to receive result.
       *                  Result is appended to existing contents.
       * @param posIter   On return, can be used to iterate over positions
       *                  of fields generated by this format call.  Field values
       *                  are defined in UDateFormatField.  Can be NULL.
       * @param status    error status.
       * @return          Reference to 'appendTo' parameter.
       * @stable ICU 4.4
       */
      UnicodeString& format(UDate date,
                            UnicodeString& appendTo,
                            FieldPositionIterator* posIter,
                            UErrorCode& status) const;
      /**
       * Formats a UDate into a date/time string. If there is a problem, you won't
       * know, using this method. Use the overloaded format() method which takes a
       * FieldPosition& to detect formatting problems.
       *
       * @param date      The UDate value to be formatted into a string.
       * @param appendTo  Output parameter to receive result.
       *                  Result is appended to existing contents.
       * @return          Reference to 'appendTo' parameter.
       * @stable ICU 2.0
       */
      UnicodeString& format(UDate date, UnicodeString& appendTo) const;
  
      /**
       * Parse a date/time string. For example, a time text "07/10/96 4:5 PM, PDT"
       * will be parsed into a UDate that is equivalent to Date(837039928046).
       * Parsing begins at the beginning of the string and proceeds as far as
       * possible.  Assuming no parse errors were encountered, this function
       * doesn't return any information about how much of the string was consumed
       * by the parsing.  If you need that information, use the version of
       * parse() that takes a ParsePosition.
       * <P>
       * By default, parsing is lenient: If the input is not in the form used by
       * this object's format method but can still be parsed as a date, then the
       * parse succeeds. Clients may insist on strict adherence to the format by
       * calling setLenient(false).
       * @see DateFormat::setLenient(boolean)
       * <P>
       * Note that the normal date formats associated with some calendars - such
       * as the Chinese lunar calendar - do not specify enough fields to enable
       * dates to be parsed unambiguously. In the case of the Chinese lunar
       * calendar, while the year within the current 60-year cycle is specified,
       * the number of such cycles since the start date of the calendar (in the
       * ERA field of the Calendar object) is not normally part of the format,
       * and parsing may assume the wrong era. For cases such as this it is
       * recommended that clients parse using the method
       * parse(const UnicodeString&, Calendar& cal, ParsePosition&)
       * with the Calendar passed in set to the current date, or to a date
       * within the era/cycle that should be assumed if absent in the format.
       *
       * @param text      The date/time string to be parsed into a UDate value.
       * @param status    Output param to be set to success/failure code. If
       *                  'text' cannot be parsed, it will be set to a failure
       *                  code.
       * @return          The parsed UDate value, if successful.
       * @stable ICU 2.0
       */
      virtual UDate parse( const UnicodeString& text,
                          UErrorCode& status) const;
  
      /**
       * Parse a date/time string beginning at the given parse position. For
       * example, a time text "07/10/96 4:5 PM, PDT" will be parsed into a Date
       * that is equivalent to Date(837039928046).
       * <P>
       * By default, parsing is lenient: If the input is not in the form used by
       * this object's format method but can still be parsed as a date, then the
       * parse succeeds. Clients may insist on strict adherence to the format by
       * calling setLenient(false).
       * @see DateFormat::setLenient(boolean)
       *
       * @param text  The date/time string to be parsed.
       * @param cal   A Calendar set on input to the date and time to be used for
       *              missing values in the date/time string being parsed, and set
       *              on output to the parsed date/time. When the calendar type is
       *              different from the internal calendar held by this DateFormat
       *              instance, the internal calendar will be cloned to a work
       *              calendar set to the same milliseconds and time zone as the
       *              cal parameter, field values will be parsed based on the work
       *              calendar, then the result (milliseconds and time zone) will
       *              be set in this calendar.
       * @param pos   On input, the position at which to start parsing; on
       *              output, the position at which parsing terminated, or the
       *              start position if the parse failed.
       * @stable ICU 2.1
       */
      virtual void parse( const UnicodeString& text,
                          Calendar& cal,
                          ParsePosition& pos) const = 0;
  
      /**
       * Parse a date/time string beginning at the given parse position. For
       * example, a time text "07/10/96 4:5 PM, PDT" will be parsed into a Date
       * that is equivalent to Date(837039928046).
       * <P>
       * By default, parsing is lenient: If the input is not in the form used by
       * this object's format method but can still be parsed as a date, then the
       * parse succeeds. Clients may insist on strict adherence to the format by
       * calling setLenient(false).
       * @see DateFormat::setLenient(boolean)
       * <P>
       * Note that the normal date formats associated with some calendars - such
       * as the Chinese lunar calendar - do not specify enough fields to enable
       * dates to be parsed unambiguously. In the case of the Chinese lunar
       * calendar, while the year within the current 60-year cycle is specified,
       * the number of such cycles since the start date of the calendar (in the
       * ERA field of the Calendar object) is not normally part of the format,
       * and parsing may assume the wrong era. For cases such as this it is
       * recommended that clients parse using the method
       * parse(const UnicodeString&, Calendar& cal, ParsePosition&)
       * with the Calendar passed in set to the current date, or to a date
       * within the era/cycle that should be assumed if absent in the format.
       *
       * @param text  The date/time string to be parsed into a UDate value.
       * @param pos   On input, the position at which to start parsing; on
       *              output, the position at which parsing terminated, or the
       *              start position if the parse failed.
       * @return      A valid UDate if the input could be parsed.
       * @stable ICU 2.0
       */
      UDate parse( const UnicodeString& text,
                   ParsePosition& pos) const;
  
      /**
       * Parse a string to produce an object. This methods handles parsing of
       * date/time strings into Formattable objects with UDate types.
       * <P>
       * Before calling, set parse_pos.index to the offset you want to start
       * parsing at in the source. After calling, parse_pos.index is the end of
       * the text you parsed. If error occurs, index is unchanged.
       * <P>
       * When parsing, leading whitespace is discarded (with a successful parse),
       * while trailing whitespace is left as is.
       * <P>
       * See Format::parseObject() for more.
       *
       * @param source    The string to be parsed into an object.
       * @param result    Formattable to be set to the parse result.
       *                  If parse fails, return contents are undefined.
       * @param parse_pos The position to start parsing at. Upon return
       *                  this param is set to the position after the
       *                  last character successfully parsed. If the
       *                  source is not parsed successfully, this param
       *                  will remain unchanged.
       * @stable ICU 2.0
       */
      virtual void parseObject(const UnicodeString& source,
                               Formattable& result,
                               ParsePosition& parse_pos) const;
  
      /**
       * Create a default date/time formatter that uses the SHORT style for both
       * the date and the time.
       *
       * @return A date/time formatter which the caller owns.
       * @stable ICU 2.0
       */
      static DateFormat* U_EXPORT2 createInstance(void);
  
      /**
       * Creates a time formatter with the given formatting style for the given
       * locale.
       *
       * @param style     The given formatting style. For example,
       *                  SHORT for "h:mm a" in the US locale. Relative
       *                  time styles are not currently supported.
       * @param aLocale   The given locale.
       * @return          A time formatter which the caller owns.
       * @stable ICU 2.0
       */
      static DateFormat* U_EXPORT2 createTimeInstance(EStyle style = kDefault,
                                            const Locale& aLocale = Locale::getDefault());
  
      /**
       * Creates a date formatter with the given formatting style for the given
       * const locale.
       *
       * @param style     The given formatting style. For example, SHORT for "M/d/yy" in the
       *                  US locale. As currently implemented, relative date formatting only
       *                  affects a limited range of calendar days before or after the
       *                  current date, based on the CLDR &lt;field type="day"&gt;/&lt;relative&gt; data:
       *                  For example, in English, "Yesterday", "Today", and "Tomorrow".
       *                  Outside of this range, dates are formatted using the corresponding
       *                  non-relative style.
       * @param aLocale   The given locale.
       * @return          A date formatter which the caller owns.
       * @stable ICU 2.0
       */
      static DateFormat* U_EXPORT2 createDateInstance(EStyle style = kDefault,
                                            const Locale& aLocale = Locale::getDefault());
  
      /**
       * Creates a date/time formatter with the given formatting styles for the
       * given locale.
       *
       * @param dateStyle The given formatting style for the date portion of the result.
       *                  For example, SHORT for "M/d/yy" in the US locale. As currently
       *                  implemented, relative date formatting only affects a limited range
       *                  of calendar days before or after the current date, based on the
       *                  CLDR &lt;field type="day"&gt;/&lt;relative&gt; data: For example, in English,
       *                  "Yesterday", "Today", and "Tomorrow". Outside of this range, dates
       *                  are formatted using the corresponding non-relative style.
       * @param timeStyle The given formatting style for the time portion of the result.
       *                  For example, SHORT for "h:mm a" in the US locale. Relative
       *                  time styles are not currently supported.
       * @param aLocale   The given locale.
       * @return          A date/time formatter which the caller owns.
       * @stable ICU 2.0
       */
      static DateFormat* U_EXPORT2 createDateTimeInstance(EStyle dateStyle = kDefault,
                                                EStyle timeStyle = kDefault,
                                                const Locale& aLocale = Locale::getDefault());
  
      /**
       * Gets the set of locales for which DateFormats are installed.
       * @param count Filled in with the number of locales in the list that is returned.
       * @return the set of locales for which DateFormats are installed.  The caller
       *  does NOT own this list and must not delete it.
       * @stable ICU 2.0
       */
      static const Locale* U_EXPORT2 getAvailableLocales(int32_t& count);
  
      /**
       * Returns whether both date/time parsing in the encapsulated Calendar object and DateFormat whitespace &
       * numeric processing is lenient.
       * @stable ICU 2.0
       */
      virtual UBool isLenient(void) const;
  
      /**
       * Specifies whether date/time parsing is to be lenient.  With
       * lenient parsing, the parser may use heuristics to interpret inputs that
       * do not precisely match this object's format.  Without lenient parsing,
       * inputs must match this object's format more closely.
       * 
       * Note: ICU 53 introduced finer grained control of leniency (and added 
       * new control points) making the preferred method a combination of 
       * setCalendarLenient() & setBooleanAttribute() calls. 
       * This method supports prior functionality but may not support all 
       * future leniency control & behavior of DateFormat. For control of pre 53 leniency,  
       * Calendar and DateFormat whitespace & numeric tolerance, this method is safe to 
       * use. However, mixing leniency control via this method and modification of the 
       * newer attributes via setBooleanAttribute() may produce undesirable 
       * results.
       *
       * @param lenient  True specifies date/time interpretation to be lenient.
       * @see Calendar::setLenient
       * @stable ICU 2.0     
       */
      virtual void setLenient(UBool lenient);
  
  
      /* Cannot use #ifndef U_HIDE_DRAFT_API for the following draft method since it is virtual */
      /**
       * Returns whether date/time parsing in the encapsulated Calendar object processing is lenient.
       * @draft ICU 53
       */
      virtual UBool isCalendarLenient(void) const;
  
  
      /* Cannot use #ifndef U_HIDE_DRAFT_API for the following draft method since it is virtual */
      /**
       * Specifies whether encapsulated Calendar date/time parsing is to be lenient.  With
       * lenient parsing, the parser may use heuristics to interpret inputs that
       * do not precisely match this object's format.  Without lenient parsing,
       * inputs must match this object's format more closely.
       * @param lenient when true, parsing is lenient
       * @see com.ibm.icu.util.Calendar#setLenient
       * @draft ICU 53
       */
      virtual void setCalendarLenient(UBool lenient);
  
  
      /**
       * Gets the calendar associated with this date/time formatter.
       * The calendar is owned by the formatter and must not be modified.
       * Also, the calendar does not reflect the results of a parse operation.
       * To parse to a calendar, use {@link #parse(const UnicodeString&, Calendar& cal, ParsePosition&) const parse(const UnicodeString&, Calendar& cal, ParsePosition&)}
       * @return the calendar associated with this date/time formatter.
       * @stable ICU 2.0
       */
      virtual const Calendar* getCalendar(void) const;
  
      /**
       * Set the calendar to be used by this date format. Initially, the default
       * calendar for the specified or default locale is used.  The caller should
       * not delete the Calendar object after it is adopted by this call.
       * Adopting a new calendar will change to the default symbols.
       *
       * @param calendarToAdopt    Calendar object to be adopted.
       * @stable ICU 2.0
       */
      virtual void adoptCalendar(Calendar* calendarToAdopt);
  
      /**
       * Set the calendar to be used by this date format. Initially, the default
       * calendar for the specified or default locale is used.
       *
       * @param newCalendar Calendar object to be set.
       * @stable ICU 2.0
       */
      virtual void setCalendar(const Calendar& newCalendar);
  
  
      /**
       * Gets the number formatter which this date/time formatter uses to format
       * and parse the numeric portions of the pattern.
       * @return the number formatter which this date/time formatter uses.
       * @stable ICU 2.0
       */
      virtual const NumberFormat* getNumberFormat(void) const;
  
      /**
       * Allows you to set the number formatter.  The caller should
       * not delete the NumberFormat object after it is adopted by this call.
       * @param formatToAdopt     NumberFormat object to be adopted.
       * @stable ICU 2.0
       */
      virtual void adoptNumberFormat(NumberFormat* formatToAdopt);
  
      /**
       * Allows you to set the number formatter.
       * @param newNumberFormat  NumberFormat object to be set.
       * @stable ICU 2.0
       */
      virtual void setNumberFormat(const NumberFormat& newNumberFormat);
  
      /**
       * Returns a reference to the TimeZone used by this DateFormat's calendar.
       * @return the time zone associated with the calendar of DateFormat.
       * @stable ICU 2.0
       */
      virtual const TimeZone& getTimeZone(void) const;
  
      /**
       * Sets the time zone for the calendar of this DateFormat object. The caller
       * no longer owns the TimeZone object and should not delete it after this call.
       * @param zoneToAdopt the TimeZone to be adopted.
       * @stable ICU 2.0
       */
      virtual void adoptTimeZone(TimeZone* zoneToAdopt);
  
      /**
       * Sets the time zone for the calendar of this DateFormat object.
       * @param zone the new time zone.
       * @stable ICU 2.0
       */
      virtual void setTimeZone(const TimeZone& zone);
  
      /* Cannot use #ifndef U_HIDE_DRAFT_API for the following draft method since it is virtual */
      /**
       * Set a particular UDisplayContext value in the formatter, such as
       * UDISPCTX_CAPITALIZATION_FOR_STANDALONE.
       * @param value The UDisplayContext value to set.
       * @param status Input/output status. If at entry this indicates a failure
       *               status, the function will do nothing; otherwise this will be
       *               updated with any new status from the function. 
       * @draft ICU 53
       */
      virtual void setContext(UDisplayContext value, UErrorCode& status);
  
      /* Cannot use #ifndef U_HIDE_DRAFT_API for the following draft method since it is virtual */
      /**
       * Get the formatter's UDisplayContext value for the specified UDisplayContextType,
       * such as UDISPCTX_TYPE_CAPITALIZATION.
       * @param type The UDisplayContextType whose value to return
       * @param status Input/output status. If at entry this indicates a failure
       *               status, the function will do nothing; otherwise this will be
       *               updated with any new status from the function. 
       * @return The UDisplayContextValue for the specified type.
       * @draft ICU 53
       */
      virtual UDisplayContext getContext(UDisplayContextType type, UErrorCode& status) const;
  
     /* Cannot use #ifndef U_HIDE_DRAFT_API for the following draft method since it is virtual */
     /**
       * Sets an boolean attribute on this DateFormat.
       * May return U_UNSUPPORTED_ERROR if this instance does not support
       * the specified attribute.
       * @param attr the attribute to set
       * @param newvalue new value
       * @param status the error type
       * @return *this - for chaining (example: format.setAttribute(...).setAttribute(...) )
       * @draft ICU 53
       */
  
      virtual DateFormat&  U_EXPORT2 setBooleanAttribute(UDateFormatBooleanAttribute attr,
      									UBool newvalue,
      									UErrorCode &status);
  
      /* Cannot use #ifndef U_HIDE_DRAFT_API for the following draft method since it is virtual */
      /**
       * Returns a boolean from this DateFormat
       * May return U_UNSUPPORTED_ERROR if this instance does not support
       * the specified attribute.
       * @param attr the attribute to set
       * @param status the error type
       * @return the attribute value. Undefined if there is an error.
       * @draft ICU 53
       */
      virtual UBool U_EXPORT2 getBooleanAttribute(UDateFormatBooleanAttribute attr, UErrorCode &status) const;
  
  protected:
      /**
       * Default constructor.  Creates a DateFormat with no Calendar or NumberFormat
       * associated with it.  This constructor depends on the subclasses to fill in
       * the calendar and numberFormat fields.
       * @stable ICU 2.0
       */
      DateFormat();
  
      /**
       * Copy constructor.
       * @stable ICU 2.0
       */
      DateFormat(const DateFormat&);
  
      /**
       * Default assignment operator.
       * @stable ICU 2.0
       */
      DateFormat& operator=(const DateFormat&);
  
      /**
       * The calendar that DateFormat uses to produce the time field values needed
       * to implement date/time formatting. Subclasses should generally initialize
       * this to the default calendar for the locale associated with this DateFormat.
       * @stable ICU 2.4
       */
      Calendar* fCalendar;
  
      /**
       * The number formatter that DateFormat uses to format numbers in dates and
       * times. Subclasses should generally initialize this to the default number
       * format for the locale associated with this DateFormat.
       * @stable ICU 2.4
       */
      NumberFormat* fNumberFormat;
  
  
  private:
      /**
       * Gets the date/time formatter with the given formatting styles for the
       * given locale.
       * @param dateStyle the given date formatting style.
       * @param timeStyle the given time formatting style.
       * @param inLocale the given locale.
       * @return a date/time formatter, or 0 on failure.
       */
      static DateFormat* U_EXPORT2 create(EStyle timeStyle, EStyle dateStyle, const Locale& inLocale);
  
       
      /**
       * enum set of active boolean attributes for this instance
       */
      EnumSet<UDateFormatBooleanAttribute, 0, UDAT_BOOLEAN_ATTRIBUTE_COUNT> fBoolFlags;
  
  
      UDisplayContext fCapitalizationContext;
  
  public:
  #ifndef U_HIDE_OBSOLETE_API
      /**
       * Field selector for FieldPosition for DateFormat fields.
       * @obsolete ICU 3.4 use UDateFormatField instead, since this API will be
       * removed in that release
       */
      enum EField
      {
          // Obsolete; use UDateFormatField instead
          kEraField = UDAT_ERA_FIELD,
          kYearField = UDAT_YEAR_FIELD,
          kMonthField = UDAT_MONTH_FIELD,
          kDateField = UDAT_DATE_FIELD,
          kHourOfDay1Field = UDAT_HOUR_OF_DAY1_FIELD,
          kHourOfDay0Field = UDAT_HOUR_OF_DAY0_FIELD,
          kMinuteField = UDAT_MINUTE_FIELD,
          kSecondField = UDAT_SECOND_FIELD,
          kMillisecondField = UDAT_FRACTIONAL_SECOND_FIELD,
          kDayOfWeekField = UDAT_DAY_OF_WEEK_FIELD,
          kDayOfYearField = UDAT_DAY_OF_YEAR_FIELD,
          kDayOfWeekInMonthField = UDAT_DAY_OF_WEEK_IN_MONTH_FIELD,
          kWeekOfYearField = UDAT_WEEK_OF_YEAR_FIELD,
          kWeekOfMonthField = UDAT_WEEK_OF_MONTH_FIELD,
          kAmPmField = UDAT_AM_PM_FIELD,
          kHour1Field = UDAT_HOUR1_FIELD,
          kHour0Field = UDAT_HOUR0_FIELD,
          kTimezoneField = UDAT_TIMEZONE_FIELD,
          kYearWOYField = UDAT_YEAR_WOY_FIELD,
          kDOWLocalField = UDAT_DOW_LOCAL_FIELD,
          kExtendedYearField = UDAT_EXTENDED_YEAR_FIELD,
          kJulianDayField = UDAT_JULIAN_DAY_FIELD,
          kMillisecondsInDayField = UDAT_MILLISECONDS_IN_DAY_FIELD,
  
          // Obsolete; use UDateFormatField instead
          ERA_FIELD = UDAT_ERA_FIELD,
          YEAR_FIELD = UDAT_YEAR_FIELD,
          MONTH_FIELD = UDAT_MONTH_FIELD,
          DATE_FIELD = UDAT_DATE_FIELD,
          HOUR_OF_DAY1_FIELD = UDAT_HOUR_OF_DAY1_FIELD,
          HOUR_OF_DAY0_FIELD = UDAT_HOUR_OF_DAY0_FIELD,
          MINUTE_FIELD = UDAT_MINUTE_FIELD,
          SECOND_FIELD = UDAT_SECOND_FIELD,
          MILLISECOND_FIELD = UDAT_FRACTIONAL_SECOND_FIELD,
          DAY_OF_WEEK_FIELD = UDAT_DAY_OF_WEEK_FIELD,
          DAY_OF_YEAR_FIELD = UDAT_DAY_OF_YEAR_FIELD,
          DAY_OF_WEEK_IN_MONTH_FIELD = UDAT_DAY_OF_WEEK_IN_MONTH_FIELD,
          WEEK_OF_YEAR_FIELD = UDAT_WEEK_OF_YEAR_FIELD,
          WEEK_OF_MONTH_FIELD = UDAT_WEEK_OF_MONTH_FIELD,
          AM_PM_FIELD = UDAT_AM_PM_FIELD,
          HOUR1_FIELD = UDAT_HOUR1_FIELD,
          HOUR0_FIELD = UDAT_HOUR0_FIELD,
          TIMEZONE_FIELD = UDAT_TIMEZONE_FIELD
      };
  #endif  /* U_HIDE_OBSOLETE_API */
  };
  
  U_NAMESPACE_END
  
  #endif /* #if !UCONFIG_NO_FORMATTING */
  
  #endif // _DATEFMT
  //eof
  