dateformat.java

gcc的组建

  }

  /**
   * This method formats the specified <code>Object</code> into a date string
   * and appends it to the specified <code>StringBuffer</code>.
   * The specified object must be an instance of <code>Number</code> or
   * <code>Date</code> or an <code>IllegalArgumentException</code> will be
   * thrown.
   *
   * @param obj The <code>Object</code> to format.
   * @param buf The <code>StringBuffer</code> to append the resultant
   * <code>String</code> to.
   * @param pos Is updated to the start and end index of the
   * specified field.
   *
   * @return The <code>StringBuffer</code> supplied on input, with the
   * formatted date/time appended.
   */
  public final StringBuffer format (Object obj,
				    StringBuffer buf, FieldPosition pos)
  {
    if (obj instanceof Number)
      obj = new Date(((Number) obj).longValue());
    else if (! (obj instanceof Date))
      throw new IllegalArgumentException
	("Cannot format given Object as a Date");

    return format ((Date) obj, buf, pos);
  }

  /**  
    * Formats the date argument according to the pattern specified. 
    *
    * @param date The formatted date.
    */
  public final String format (Date date)
  {
    StringBuffer sb = new StringBuffer ();
    format (date, sb, new FieldPosition (MONTH_FIELD));
    return sb.toString();
  }

  /**
   * This method formats a <code>Date</code> into a string and appends it
   * to the specified <code>StringBuffer</code>.
   *
   * @param date The <code>Date</code> value to format.
   * @param buf The <code>StringBuffer</code> to append the resultant
   * <code>String</code> to.
   * @param pos Is updated to the start and end index of the
   * specified field.
   *
   * @return The <code>StringBuffer</code> supplied on input, with the
   * formatted date/time appended.
   */
  public abstract StringBuffer format (Date date,
				       StringBuffer buf, FieldPosition pos);

  /**
   * This method returns a list of available locales supported by this
   * class.
   */
  public static Locale[] getAvailableLocales()
  {
    // FIXME
    Locale[] l = new Locale[1];
    l[0] = Locale.US;
    return l;
  }

  /**
    * This method returns the <code>Calendar</code> object being used by
    * this object to parse/format datetimes.
    *
    * @return The <code>Calendar</code> being used by this object.
    *
    * @see java.util.Calendar
    */
  public Calendar getCalendar ()
  {
    return calendar;
  }

  private static DateFormat computeInstance (int style, Locale loc,
                                             boolean use_date, boolean use_time)
  {
    return computeInstance (style, style, loc, use_date, use_time);
  }

  private static DateFormat computeInstance (int dateStyle, int timeStyle,
                                             Locale loc, boolean use_date,
                                             boolean use_time)
  {
    ResourceBundle res;
    try
      {
	res = ResourceBundle.getBundle("gnu.java.locale.LocaleInformation",
				       loc, ClassLoader.getSystemClassLoader());
      }
    catch (MissingResourceException x)
      {
	res = null;
      }

    String pattern = null;
    if (use_date)
      {
	String name, def;
	switch (dateStyle)
	  {
	  case FULL:
	    name = "fullDateFormat";
	    def = "EEEE MMMM d, yyyy G";
	    break;
	  case LONG:
	    name = "longDateFormat";
	    def = "MMMM d, yyyy";
	    break;
	  case MEDIUM:
	    name = "mediumDateFormat";
	    def = "d-MMM-yy";
	    break;
	  case SHORT:
	    name = "shortDateFormat";
	    def = "M/d/yy";
	    break;
	  default:
	    throw new IllegalArgumentException ();
	  }
	try
	  {
	    pattern = res == null ? def : res.getString(name);
	  }
	catch (MissingResourceException x)
	  {
	    pattern = def;
	  }
      }

    if (use_time)
      {
	if (pattern == null)
	  pattern = "";
	else
	  pattern += " ";

	String name, def;
	switch (timeStyle)
	  {
	  case FULL:
	    name = "fullTimeFormat";
	    def = "h:mm:ss;S 'o''clock' a z";
	    break;
	  case LONG:
	    name = "longTimeFormat";
	    def = "h:mm:ss a z";
	    break;
	  case MEDIUM:
	    name = "mediumTimeFormat";
	    def = "h:mm:ss a";
	    break;
	  case SHORT:
	    name = "shortTimeFormat";
	    def = "h:mm a";
	    break;
	  default:
	    throw new IllegalArgumentException ();
	  }

	String s;
	try
	  {
	    s = res == null ? def : res.getString(name);
	  }
	catch (MissingResourceException x)
	  {
	    s = def;
	  }
	pattern += s;
      }

    return new SimpleDateFormat (pattern, loc);
  }

 /**
   * This method returns an instance of <code>DateFormat</code> that will
   * format using the default formatting style for dates.
   *
   * @return A new <code>DateFormat</code> instance.
   */
  public static final DateFormat getDateInstance ()
  {
    return getDateInstance (DEFAULT, Locale.getDefault());
  }

  /**
   * This method returns an instance of <code>DateFormat</code> that will
   * format using the specified formatting style for dates.
   *
   * @param style The type of formatting to perform. 
   * 
   * @return A new <code>DateFormat</code> instance.
   */
  public static final DateFormat getDateInstance (int style)
  {
    return getDateInstance (style, Locale.getDefault());
  }

  /**
   * This method returns an instance of <code>DateFormat</code> that will
   * format using the specified formatting style for dates.  The specified
   * localed will be used in place of the default.
   *
   * @param style The type of formatting to perform. 
   * @param loc The desired locale.
   * 
   * @return A new <code>DateFormat</code> instance.
   */
  public static final DateFormat getDateInstance (int style, Locale loc)
  {
    return computeInstance (style, loc, true, false);
  }

  /**
   * This method returns a new instance of <code>DateFormat</code> that
   * formats both dates and times using the <code>SHORT</code> style.
   *
   * @return A new <code>DateFormat</code>instance.
   */
  public static final DateFormat getDateTimeInstance ()
  {
    return getDateTimeInstance (DEFAULT, DEFAULT, Locale.getDefault());
  }

  /**
   * This method returns a new instance of <code>DateFormat</code> that
   * formats both dates and times using the <code>DEFAULT</code> style.
   *
   * @return A new <code>DateFormat</code>instance.
   */
  public static final DateFormat getDateTimeInstance (int dateStyle, 
						      int timeStyle)
  {
    return getDateTimeInstance (dateStyle, timeStyle, Locale.getDefault());
  }

  /**
   * This method returns a new instance of <code>DateFormat</code> that
   * formats both dates and times using the specified styles.
   * 
   * @param dateStyle The desired style for date formatting.
   * @param timeStyle The desired style for time formatting
   *
   * @return A new <code>DateFormat</code>instance.
   */
  public static final DateFormat getDateTimeInstance (int dateStyle, 
						      int timeStyle, 
						      Locale loc)
  {
    return computeInstance (dateStyle, timeStyle, loc, true, true);
  }

  /**
   * This method returns a new instance of <code>DateFormat</code> that
   * formats both dates and times using the <code>SHORT</code> style.
   *
   * @return A new <code>DateFormat</code>instance.
   */
  public static final DateFormat getInstance ()
  {
    // JCL book says SHORT.
    return getDateTimeInstance (SHORT, SHORT, Locale.getDefault());
  }

  /**
   * This method returns the <code>NumberFormat</code> object being used
   * by this object to parse/format time values.
   *
   * @return The <code>NumberFormat</code> in use by this object.
   */
  public NumberFormat getNumberFormat ()
  {
    return numberFormat;
  }

 /**
   * This method returns an instance of <code>DateFormat</code> that will
   * format using the default formatting style for times.
   *
   * @return A new <code>DateFormat</code> instance.
   */
  public static final DateFormat getTimeInstance ()
  {
    return getTimeInstance (DEFAULT, Locale.getDefault());
  }

  /**
   * This method returns an instance of <code>DateFormat</code> that will
   * format using the specified formatting style for times.
   *
   * @param style The type of formatting to perform. 
   * 
   * @return A new <code>DateFormat</code> instance.
   */
  public static final DateFormat getTimeInstance (int style)
  {
    return getTimeInstance (style, Locale.getDefault());
  }

  /**
   * This method returns an instance of <code>DateFormat</code> that will
   * format using the specified formatting style for times.  The specified
   * localed will be used in place of the default.
   *
   * @param style The type of formatting to perform. 
   * @param loc The desired locale.
   * 
   * @return A new <code>DateFormat</code> instance.
   */
  public static final DateFormat getTimeInstance (int style, Locale loc)
  {
    return computeInstance (style, loc, false, true);
  }

  /**
   * This method returns the <code>TimeZone</code> object being used by
   * this instance.
   *
   * @return The time zone in use.
   */
  public TimeZone getTimeZone ()
  {
    return calendar.getTimeZone();
  }

  /**
   * This method returns a hash value for this object.
   * 
   * @return A hash value for this object.
   */
  public int hashCode ()
  {
    if (numberFormat != null)
      return numberFormat.hashCode();
    else
      return 0;
  }

  /**
   * This method indicates whether or not the parsing of date and time
   * values should be done in a lenient value.
   *
   * @return <code>true</code> if date/time parsing is lenient,
   * <code>false</code> otherwise.
   */
  public boolean isLenient ()
  {
    return calendar.isLenient();
  }

  /**
   * This method parses the specified date/time string.
   *
   * @param source The string to parse.
   * @return The resultant date.
   *
   * @exception ParseException If the specified string cannot be parsed.
   */
  public Date parse (String source) throws ParseException
  {
    ParsePosition pos = new ParsePosition(0);
    Date result = parse (source, pos);
    if (result == null)
      {
	int index = pos.getErrorIndex();
	if (index < 0)
	  index = pos.getIndex();
	throw new ParseException("invalid Date syntax in \""
				 + source + '\"', index);
      }
    return result;
  }

  /** 
   * This method parses the specified <code>String</code> into a 
   * <code>Date</code>.  The <code>pos</code> argument contains the
   * starting parse position on method entry and the ending parse
   * position on method exit.
   *
   * @param source The string to parse.
   * @param pos The starting parse position in entry, the ending parse
   * position on exit.
   *
   * @return The parsed date, or <code>null</code> if the string cannot
   * be parsed.
   */
  public abstract Date parse (String source, ParsePosition pos);

  /**
   * This method is identical to <code>parse(String, ParsePosition)</code>,
   * but returns its result as an <code>Object</code> instead of a
   * <code>Date</code>.
   * 
   * @param source The string to parse.
   * @param pos The starting parse position in entry, the ending parse
   * position on exit.
   *
   * @return The parsed date, or <code>null</code> if the string cannot
   * be parsed.
   */
  public Object parseObject (String source, ParsePosition pos)
  {
    return parse(source, pos);
  }

  /**
   * This method specified the <code>Calendar</code> that should be used 
   * by this object to parse/format datetimes.
   *
   * @param calendar The new <code>Calendar</code> for this object.
   *
   * @see java.util.Calendar
   */
  public void setCalendar (Calendar calendar)
  {
    this.calendar = calendar;
  }

  /**
   * This method specifies whether or not this object should be lenient in 
   * the syntax it accepts while parsing date/time values.
   *
   * @param lenient <code>true</code> if parsing should be lenient,
   * <code>false</code> otherwise.
   */
  public void setLenient (boolean lenient)
  {
    calendar.setLenient(lenient);
  }

  /**
   * This method specifies the <code>NumberFormat</code> object that should
   * be used by this object to parse/format times.
   *
   * @param numberFormat The <code>NumberFormat</code> in use by this object.
   */
  public void setNumberFormat (NumberFormat numberFormat)
  {
    this.numberFormat = numberFormat;
  }

  /**
   * This method sets the time zone that should be used by this object.
   *
   * @param timeZone The new time zone.
   */
  public void setTimeZone (TimeZone timeZone)
  {
    calendar.setTimeZone(timeZone);
  }
}