calendar.java

gcc的组建

  {
    return ResourceBundle.getBundle(bundleName, locale,
                                    ClassLoader.getSystemClassLoader());
  }

  /**
   * Constructs a new Calendar with the default time zone and the default
   * locale.
   */
  protected Calendar()
  {
    this(TimeZone.getDefault(), Locale.getDefault());
  }

  /**
   * Constructs a new Calendar with the given time zone and the given
   * locale.
   * @param zone a time zone.
   * @param locale a locale.
   */
  protected Calendar(TimeZone zone, Locale locale)
  {
    this.zone = zone;
    lenient = true;

    ResourceBundle rb = getBundle(locale);

    firstDayOfWeek = ((Integer) rb.getObject("firstDayOfWeek")).intValue();
    minimalDaysInFirstWeek = ((Integer) rb.getObject("minimalDaysInFirstWeek"))
                             .intValue();
    clear();
  }

  /**
   * Creates a calendar representing the actual time, using the default
   * time zone and locale.
   */
  public static synchronized Calendar getInstance()
  {
    return getInstance(TimeZone.getDefault(), Locale.getDefault());
  }

  /**
   * Creates a calendar representing the actual time, using the given
   * time zone and the default locale.
   * @param zone a time zone.
   */
  public static synchronized Calendar getInstance(TimeZone zone)
  {
    return getInstance(zone, Locale.getDefault());
  }

  /**
   * Creates a calendar representing the actual time, using the default
   * time zone and the given locale.
   * @param locale a locale.
   */
  public static synchronized Calendar getInstance(Locale locale)
  {
    return getInstance(TimeZone.getDefault(), locale);
  }

  /**
   * Cache of locale->calendar-class mappings. This avoids having to do a ResourceBundle
   * lookup for every getInstance call.
   */
  private static HashMap cache = new HashMap();

  /** Preset argument types for calendar-class constructor lookup.  */
  private static Class[] ctorArgTypes = new Class[]
                                        {
                                          TimeZone.class, Locale.class
                                        };

  /**
   * Creates a calendar representing the actual time, using the given
   * time zone and locale.
   * @param zone a time zone.
   * @param locale a locale.
   */
  public static synchronized Calendar getInstance(TimeZone zone, Locale locale)
  {
    Class calendarClass = (Class) cache.get(locale);
    Throwable exception = null;

    try
      {
	if (calendarClass == null)
	  {
	    ResourceBundle rb = getBundle(locale);
	    String calendarClassName = rb.getString("calendarClass");

	    if (calendarClassName != null)
	      {
		calendarClass = Class.forName(calendarClassName);
		if (Calendar.class.isAssignableFrom(calendarClass))
		  cache.put(locale, calendarClass);
	      }
	  }

	// GregorianCalendar is by far the most common case. Optimize by 
	// avoiding reflection.
	if (calendarClass == GregorianCalendar.class)
	  return new GregorianCalendar(zone, locale);

	if (Calendar.class.isAssignableFrom(calendarClass))
	  {
	    Constructor ctor = calendarClass.getConstructor(ctorArgTypes);
	    return (Calendar) ctor.newInstance(new Object[] { zone, locale });
	  }
      }
    catch (ClassNotFoundException ex)
      {
	exception = ex;
      }
    catch (IllegalAccessException ex)
      {
	exception = ex;
      }
    catch (NoSuchMethodException ex)
      {
	exception = ex;
      }
    catch (InstantiationException ex)
      {
	exception = ex;
      }
    catch (InvocationTargetException ex)
      {
	exception = ex;
      }

    throw new RuntimeException("Error instantiating calendar for locale "
                               + locale, exception);
  }

  /**
   * Gets the set of locales for which a Calendar is available.
   * @exception MissingResourceException if locale data couldn't be found.
   * @return the set of locales.
   */
  public static synchronized Locale[] getAvailableLocales()
  {
    ResourceBundle rb = getBundle(new Locale("", ""));
    return (Locale[]) rb.getObject("availableLocales");
  }

  /**
   * Converts the time field values (<code>fields</code>) to
   * milliseconds since the epoch UTC (<code>time</code>).  Override
   * this method if you write your own Calendar.  */
  protected abstract void computeTime();

  /**
   * Converts the milliseconds since the epoch UTC
   * (<code>time</code>) to time fields
   * (<code>fields</code>). Override this method if you write your
   * own Calendar.
   */
  protected abstract void computeFields();

  /**
   * Converts the time represented by this object to a
   * <code>Date</code>-Object.
   * @return the Date.
   */
  public final Date getTime()
  {
    if (! isTimeSet)
      computeTime();
    return new Date(time);
  }

  /**
   * Sets this Calendar's time to the given Date.  All time fields
   * are invalidated by this method.
   */
  public final void setTime(Date date)
  {
    setTimeInMillis(date.getTime());
  }

  /**
   * Returns the time represented by this Calendar.
   * @return the time in milliseconds since the epoch.
   * @specnote This was made public in 1.4.
   */
  public long getTimeInMillis()
  {
    if (! isTimeSet)
      computeTime();
    return time;
  }

  /**
   * Sets this Calendar's time to the given Time.  All time fields
   * are invalidated by this method.
   * @param time the time in milliseconds since the epoch
   * @specnote This was made public in 1.4.
   */
  public void setTimeInMillis(long time)
  {
    clear();
    this.time = time;
    isTimeSet = true;
    computeFields();
  }

  /**
   * Gets the value of the specified field.  They are recomputed
   * if they are invalid.
   * @param field the time field. One of the time field constants.
   * @return the value of the specified field
   * @throws ArrayIndexOutOfBoundsException if the field is outside
   *         the valid range.  The value of field must be >= 0 and
   *         <= <code>FIELD_COUNT</code>.
   * @specnote Not final since JDK 1.4
   */
  public int get(int field)
  {
    // If the requested field is invalid, force all fields to be recomputed.
    if (! isSet[field])
      areFieldsSet = false;
    complete();
    return fields[field];
  }

  /**
   * Gets the value of the specified field. This method doesn't
   * recompute the fields, if they are invalid.
   * @param field the time field. One of the time field constants.
   * @return the value of the specified field, undefined if
   * <code>areFieldsSet</code> or <code>isSet[field]</code> is false.
   * @throws ArrayIndexOutOfBoundsException if the field is outside
   *         the valid range.  The value of field must be >= 0 and
   *         <= <code>FIELD_COUNT</code>.
   */
  protected final int internalGet(int field)
  {
    return fields[field];
  }

  /**
   * Sets the time field with the given value.  This does invalidate
   * the time in milliseconds.
   * @param field the time field. One of the time field constants
   * @param value the value to be set.
   * @throws ArrayIndexOutOfBoundsException if field is outside
   *         the valid range.  The value of field must be >= 0 and
   *         <= <code>FIELD_COUNT</code>.
   * @specnote Not final since JDK 1.4
   */
  public void set(int field, int value)
  {
    if (isTimeSet)
      for (int i = 0; i < FIELD_COUNT; i++)
	isSet[i] = false;
    isTimeSet = false;
    fields[field] = value;
    isSet[field] = true;

    // The five valid date patterns, in order of priority
    // 1  YEAR + MONTH + DAY_OF_MONTH
    // 2  YEAR + MONTH + WEEK_OF_MONTH + DAY_OF_WEEK
    // 3  YEAR + MONTH + DAY_OF_WEEK_IN_MONTH + DAY_OF_WEEK
    // 4  YEAR + DAY_OF_YEAR
    // 5  YEAR + DAY_OF_WEEK + WEEK_OF_YEAR
    switch (field)
      {
      case MONTH: // pattern 1,2 or 3
	isSet[DAY_OF_YEAR] = false;
	isSet[WEEK_OF_YEAR] = false;
	break;
      case DAY_OF_MONTH: // pattern 1
	isSet[YEAR] = true;
	isSet[MONTH] = true;
	isSet[WEEK_OF_MONTH] = true;
	isSet[DAY_OF_WEEK] = false;
	isSet[DAY_OF_WEEK_IN_MONTH] = false;
	isSet[DAY_OF_YEAR] = false;
	isSet[WEEK_OF_YEAR] = false;
	break;
      case WEEK_OF_MONTH: // pattern 2
	if (! isSet[DAY_OF_WEEK])
	  fields[DAY_OF_WEEK] = getFirstDayOfWeek();
	isSet[YEAR] = true;
	isSet[MONTH] = true;
	isSet[DAY_OF_WEEK] = true;
	isSet[DAY_OF_MONTH] = false;
	isSet[DAY_OF_WEEK_IN_MONTH] = false;
	isSet[DAY_OF_YEAR] = false;
	isSet[WEEK_OF_YEAR] = false;
	break;
      case DAY_OF_WEEK_IN_MONTH: // pattern 3
	if (! isSet[DAY_OF_WEEK])
	  fields[DAY_OF_WEEK] = getFirstDayOfWeek();
	isSet[YEAR] = true;
	isSet[MONTH] = true;
	isSet[DAY_OF_WEEK] = true;
	isSet[DAY_OF_YEAR] = false;
	isSet[DAY_OF_MONTH] = false;
	isSet[WEEK_OF_MONTH] = false;
	isSet[WEEK_OF_YEAR] = false;
	break;
      case DAY_OF_YEAR: // pattern 4
	isSet[YEAR] = true;
	isSet[MONTH] = false;
	isSet[WEEK_OF_MONTH] = false;
	isSet[DAY_OF_MONTH] = false;
	isSet[DAY_OF_WEEK] = false;
	isSet[WEEK_OF_YEAR] = false;
	isSet[DAY_OF_WEEK_IN_MONTH] = false;
	break;
      case WEEK_OF_YEAR: // pattern 5
	if (! isSet[DAY_OF_WEEK])
	  fields[DAY_OF_WEEK] = getFirstDayOfWeek();
	isSet[YEAR] = true;
	isSet[DAY_OF_WEEK] = true;
	isSet[MONTH] = false;
	isSet[DAY_OF_MONTH] = false;
	isSet[WEEK_OF_MONTH] = false;
	isSet[DAY_OF_YEAR] = false;
	isSet[DAY_OF_WEEK_IN_MONTH] = false;
	break;
      case AM_PM:
	isSet[HOUR] = true;
	isSet[HOUR_OF_DAY] = false;
	break;
      case HOUR_OF_DAY:
	isSet[AM_PM] = false;
	isSet[HOUR] = false;
	break;
      case HOUR:
	isSet[AM_PM] = true;
	isSet[HOUR_OF_DAY] = false;
	break;
      case DST_OFFSET:
	explicitDSTOffset = true;
      }

    // May have crossed over a DST boundary.
    if (! explicitDSTOffset && (field != DST_OFFSET && field != ZONE_OFFSET))
      isSet[DST_OFFSET] = false;
  }

  /**
   * Sets the fields for year, month, and date
   * @param year the year.
   * @param month the month, one of the constants JANUARY..UNDICEMBER.
   * @param date the day of the month
   */
  public final void set(int year, int month, int date)
  {
    isTimeSet = false;
    fields[YEAR] = year;
    fields[MONTH] = month;
    fields[DATE] = date;
    isSet[YEAR] = isSet[MONTH] = isSet[DATE] = true;
    isSet[WEEK_OF_YEAR] = false;
    isSet[DAY_OF_YEAR] = false;
    isSet[WEEK_OF_MONTH] = false;
    isSet[DAY_OF_WEEK] = false;
    isSet[DAY_OF_WEEK_IN_MONTH] = false;
    isSet[ERA] = false;

    if (! explicitDSTOffset)
      isSet[DST_OFFSET] = false; // May have crossed a DST boundary.
  }

  /**
   * Sets the fields for year, month, date, hour, and minute
   * @param year the year.
   * @param month the month, one of the constants JANUARY..UNDICEMBER.
   * @param date the day of the month
   * @param hour the hour of day.
   * @param minute the minute.
   */
  public final void set(int year, int month, int date, int hour, int minute)
  {
    set(year, month, date);
    fields[HOUR_OF_DAY] = hour;
    fields[MINUTE] = minute;
    isSet[HOUR_OF_DAY] = isSet[MINUTE] = true;
    isSet[AM_PM] = false;
    isSet[HOUR] = false;
  }

  /**
   * Sets the fields for year, month, date, hour, and minute
   * @param year the year.
   * @param month the month, one of the constants JANUARY..UNDICEMBER.
   * @param date the day of the month
   * @param hour the hour of day.
   * @param minute the minute.
   * @param second the second.
   */
  public final void set(int year, int month, int date, int hour, int minute,
                        int second)
  {
    set(year, month, date, hour, minute);
    fields[SECOND] = second;
    isSet[SECOND] = true;
  }

  /**
   * Clears the values of all the time fields.
   */
  public final void clear()
  {
    isTimeSet = false;
    areFieldsSet = false;
    int zoneOffs = zone.getRawOffset();
    int[] tempFields = 
                       {
                         1, 1970, JANUARY, 1, 1, 1, 1, THURSDAY, 1, AM, 0, 0, 0,
                         0, 0, zoneOffs, 0
                       };
    fields = tempFields;
    for (int i = 0; i < FIELD_COUNT; i++)
      isSet[i] = false;
  }

  /**
   * Clears the values of the specified time field.
   * @param field the time field. One of the time field constants.
   * @throws ArrayIndexOutOfBoundsException if field is outside