simpledateformat.java

gcc的组建

    this(pattern, Locale.getDefault());
  }

  /**
   * Creates a date formatter using the specified non-localized pattern,
   * with the default DateFormatSymbols for the given locale.
   *
   * @param pattern the non-localized pattern to use.
   * @param locale the locale to use for the formatting symbols.
   * @throws NullPointerException if the pattern is null.
   * @throws IllegalArgumentException if the pattern is invalid.
   */
  public SimpleDateFormat(String pattern, Locale locale) 
  {
    super();
    calendar = new GregorianCalendar(locale);
    computeCenturyStart();
    tokens = new ArrayList();
    formatData = new DateFormatSymbols(locale);
    compileFormat(pattern);
    this.pattern = pattern;
    numberFormat = NumberFormat.getInstance(locale);
    numberFormat.setGroupingUsed (false);
    numberFormat.setParseIntegerOnly (true);
    numberFormat.setMaximumFractionDigits (0);
  }

  /**
   * Creates a date formatter using the specified non-localized
   * pattern. The specified DateFormatSymbols will be used when
   * formatting.
   *
   * @param pattern the non-localized pattern to use.
   * @param formatData the formatting symbols to use.
   * @throws NullPointerException if the pattern or formatData is null.
   * @throws IllegalArgumentException if the pattern is invalid.
   */
  public SimpleDateFormat(String pattern, DateFormatSymbols formatData)
  {
    super();
    calendar = new GregorianCalendar();
    computeCenturyStart ();
    tokens = new ArrayList();
    if (formatData == null)
      throw new NullPointerException("formatData");
    this.formatData = formatData;
    compileFormat(pattern);
    this.pattern = pattern;
    numberFormat = NumberFormat.getInstance();
    numberFormat.setGroupingUsed (false);
    numberFormat.setParseIntegerOnly (true);
    numberFormat.setMaximumFractionDigits (0);
  }

  /**
   * This method returns a string with the formatting pattern being used
   * by this object.  This string is unlocalized.
   *
   * @return The format string.
   */
  public String toPattern()
  {
    return pattern;
  }

  /**
   * This method returns a string with the formatting pattern being used
   * by this object.  This string is localized.
   *
   * @return The format string.
   */
  public String toLocalizedPattern()
  {
    String localChars = formatData.getLocalPatternChars();
    return translateLocalizedPattern(pattern, standardChars, localChars);
  }

  /**
   * This method sets the formatting pattern that should be used by this
   * object.  This string is not localized.
   *
   * @param pattern The new format pattern.
   * @throws NullPointerException if the pattern is null.
   * @throws IllegalArgumentException if the pattern is invalid.
   */
  public void applyPattern(String pattern)
  {
    tokens = new ArrayList();
    compileFormat(pattern);
    this.pattern = pattern;
  }

  /**
   * This method sets the formatting pattern that should be used by this
   * object.  This string is localized.
   *
   * @param pattern The new format pattern.
   * @throws NullPointerException if the pattern is null.
   * @throws IllegalArgumentException if the pattern is invalid.
   */
  public void applyLocalizedPattern(String pattern)
  {
    String localChars = formatData.getLocalPatternChars();
    pattern = translateLocalizedPattern(pattern, localChars, standardChars);
    applyPattern(pattern);
  }

  /**
   * Translates either from or to a localized variant of the pattern
   * string.  For example, in the German locale, 't' (for 'tag') is
   * used instead of 'd' (for 'date').  This method translates
   * a localized pattern (such as 'ttt') to a non-localized pattern
   * (such as 'ddd'), or vice versa.  Non-localized patterns use
   * a standard set of characters, which match those of the U.S. English
   * locale.
   *
   * @param pattern the pattern to translate.
   * @param oldChars the old set of characters (used in the pattern).
   * @param newChars the new set of characters (which will be used in the
   *                 pattern).
   * @return a version of the pattern using the characters in
   *         <code>newChars</code>.
   */
  private String translateLocalizedPattern(String pattern,
					   String oldChars, String newChars)
  {
    int len = pattern.length();
    StringBuffer buf = new StringBuffer(len);
    boolean quoted = false;
    for (int i = 0;  i < len;  i++)
      {
	char ch = pattern.charAt(i);
	if (ch == '\'')
	  quoted = ! quoted;
	if (! quoted)
	  {
	    int j = oldChars.indexOf(ch);
	    if (j >= 0)
	      ch = newChars.charAt(j);
	  }
	buf.append(ch);
      }
    return buf.toString();
  }

  /** 
   * Returns the start of the century used for two digit years.
   *
   * @return A <code>Date</code> representing the start of the century
   * for two digit years.
   */
  public Date get2DigitYearStart()
  {
    return defaultCenturyStart;
  }

  /**
   * Sets the start of the century used for two digit years.
   *
   * @param date A <code>Date</code> representing the start of the century for
   * two digit years.
   */
  public void set2DigitYearStart(Date date)
  {
    defaultCenturyStart = date;
    calendar.clear();
    calendar.setTime(date);
    int year = calendar.get(Calendar.YEAR);
    defaultCentury = year - (year % 100);
  }

  /**
   * This method returns a copy of the format symbol information used
   * for parsing and formatting dates.
   *
   * @return a copy of the date format symbols.
   */
  public DateFormatSymbols getDateFormatSymbols()
  {
    return (DateFormatSymbols) formatData.clone();
  }

  /**
   * This method sets the format symbols information used for parsing
   * and formatting dates.
   *
   * @param formatData The date format symbols.
   * @throws NullPointerException if <code>formatData</code> is null.
   */
   public void setDateFormatSymbols(DateFormatSymbols formatData)
   {
     if (formatData == null)
       {
	 throw new
	   NullPointerException("The supplied format data was null.");
       }
     this.formatData = formatData;
   }

  /**
   * This methods tests whether the specified object is equal to this
   * object.  This will be true if and only if the specified object:
   * <p>
   * <ul>
   * <li>Is not <code>null</code>.</li>
   * <li>Is an instance of <code>SimpleDateFormat</code>.</li>
   * <li>Is equal to this object at the superclass (i.e., <code>DateFormat</code>)
   *     level.</li>
   * <li>Has the same formatting pattern.</li>
   * <li>Is using the same formatting symbols.</li>
   * <li>Is using the same century for two digit years.</li>
   * </ul>
   *
   * @param o The object to compare for equality against.
   *
   * @return <code>true</code> if the specified object is equal to this object,
   * <code>false</code> otherwise.
   */
  public boolean equals(Object o)
  {
    if (!super.equals(o))
      return false;

    if (!(o instanceof SimpleDateFormat))
      return false;

    SimpleDateFormat sdf = (SimpleDateFormat)o;

    if (defaultCentury != sdf.defaultCentury)
      return false;

    if (!toPattern().equals(sdf.toPattern()))
      return false;

    if (!getDateFormatSymbols().equals(sdf.getDateFormatSymbols()))
      return false;

    return true;
  }

  /**
   * This method returns a hash value for this object.
   *
   * @return A hash value for this object.
   */
  public int hashCode()
  {
    return super.hashCode() ^ toPattern().hashCode() ^ defaultCentury ^
      getDateFormatSymbols().hashCode();
  }


  /**
   * Formats the date input according to the format string in use,
   * appending to the specified StringBuffer.  The input StringBuffer
   * is returned as output for convenience.
   */
  private void formatWithAttribute(Date date, FormatBuffer buffer, FieldPosition pos)
  {
    String temp;
    AttributedCharacterIterator.Attribute attribute;
    calendar.setTime(date);

    // go through vector, filling in fields where applicable, else toString
    Iterator iter = tokens.iterator();
    while (iter.hasNext())
      {
	Object o = iter.next();
	if (o instanceof CompiledField)
	  {
	    CompiledField cf = (CompiledField) o;
	    int beginIndex = buffer.length();
	    
	    switch (cf.getField())
	      {
	      case ERA_FIELD:
		buffer.append (formatData.eras[calendar.get (Calendar.ERA)], DateFormat.Field.ERA);
		break;
	      case YEAR_FIELD:
		// If we have two digits, then we truncate.  Otherwise, we
		// use the size of the pattern, and zero pad.
		buffer.setDefaultAttribute (DateFormat.Field.YEAR);
		if (cf.getSize() == 2)
		  {
		    temp = "00"+String.valueOf (calendar.get (Calendar.YEAR));
		    buffer.append (temp.substring (temp.length() - 2));
		  }
		else
		  withLeadingZeros (calendar.get (Calendar.YEAR), cf.getSize(), buffer);
		break;
	      case MONTH_FIELD:
		buffer.setDefaultAttribute (DateFormat.Field.MONTH);
		if (cf.getSize() < 3)
		  withLeadingZeros (calendar.get (Calendar.MONTH) + 1, cf.getSize(), buffer);
		else if (cf.getSize() < 4)
		  buffer.append (formatData.shortMonths[calendar.get (Calendar.MONTH)]);
		else
		  buffer.append (formatData.months[calendar.get (Calendar.MONTH)]);
		break;
	      case DATE_FIELD:
		buffer.setDefaultAttribute (DateFormat.Field.DAY_OF_MONTH);
		withLeadingZeros (calendar.get (Calendar.DATE), cf.getSize(), buffer);
		break;
	      case HOUR_OF_DAY1_FIELD: // 1-24
		buffer.setDefaultAttribute(DateFormat.Field.HOUR_OF_DAY1);
		withLeadingZeros ( ((calendar.get (Calendar.HOUR_OF_DAY) + 23) % 24) + 1, 
				   cf.getSize(), buffer);
		break;
	      case HOUR_OF_DAY0_FIELD: // 0-23
		buffer.setDefaultAttribute (DateFormat.Field.HOUR_OF_DAY0);
		withLeadingZeros (calendar.get (Calendar.HOUR_OF_DAY), cf.getSize(), buffer);
		break;
	      case MINUTE_FIELD:
		buffer.setDefaultAttribute (DateFormat.Field.MINUTE);
		withLeadingZeros (calendar.get (Calendar.MINUTE),
				  cf.getSize(), buffer);
		break;
	      case SECOND_FIELD:
		buffer.setDefaultAttribute (DateFormat.Field.SECOND);
		withLeadingZeros(calendar.get (Calendar.SECOND), 
				 cf.getSize(), buffer);
		break;
	      case MILLISECOND_FIELD:
		buffer.setDefaultAttribute (DateFormat.Field.MILLISECOND);
		withLeadingZeros (calendar.get (Calendar.MILLISECOND), cf.getSize(), buffer);
		break;
	      case DAY_OF_WEEK_FIELD:
		buffer.setDefaultAttribute (DateFormat.Field.DAY_OF_WEEK);
		if (cf.getSize() < 4)
		  buffer.append (formatData.shortWeekdays[calendar.get (Calendar.DAY_OF_WEEK)]);
		else
		  buffer.append (formatData.weekdays[calendar.get (Calendar.DAY_OF_WEEK)]);
		break;
	      case DAY_OF_YEAR_FIELD:
		buffer.setDefaultAttribute (DateFormat.Field.DAY_OF_YEAR);
		withLeadingZeros (calendar.get (Calendar.DAY_OF_YEAR), cf.getSize(), buffer);
		break;
	      case DAY_OF_WEEK_IN_MONTH_FIELD:
		buffer.setDefaultAttribute (DateFormat.Field.DAY_OF_WEEK_IN_MONTH);
		withLeadingZeros (calendar.get (Calendar.DAY_OF_WEEK_IN_MONTH), 
				 cf.getSize(), buffer);
		break;
	      case WEEK_OF_YEAR_FIELD:
		buffer.setDefaultAttribute (DateFormat.Field.WEEK_OF_YEAR);
		withLeadingZeros (calendar.get (Calendar.WEEK_OF_YEAR),
				  cf.getSize(), buffer);
		break;
	      case WEEK_OF_MONTH_FIELD:
		buffer.setDefaultAttribute (DateFormat.Field.WEEK_OF_MONTH);
		withLeadingZeros (calendar.get (Calendar.WEEK_OF_MONTH),
				  cf.getSize(), buffer);
		break;
	      case AM_PM_FIELD:
		buffer.setDefaultAttribute (DateFormat.Field.AM_PM);
		buffer.append (formatData.ampms[calendar.get (Calendar.AM_PM)]);
		break;
	      case HOUR1_FIELD: // 1-12
		buffer.setDefaultAttribute (DateFormat.Field.HOUR1);
		withLeadingZeros (((calendar.get (Calendar.HOUR) + 11) % 12) + 1,
				  cf.getSize(), buffer);
		break;
	      case HOUR0_FIELD: // 0-11
		buffer.setDefaultAttribute (DateFormat.Field.HOUR0);
		withLeadingZeros (calendar.get (Calendar.HOUR), cf.getSize(), buffer);
		break;
	      case TIMEZONE_FIELD:
		buffer.setDefaultAttribute (DateFormat.Field.TIME_ZONE);
		TimeZone zone = calendar.getTimeZone();
		boolean isDST = calendar.get (Calendar.DST_OFFSET) != 0;
		// FIXME: XXX: This should be a localized time zone.
		String zoneID = zone.getDisplayName
		  (isDST, cf.getSize() > 3 ? TimeZone.LONG : TimeZone.SHORT);
		buffer.append (zoneID);
		break;
	      case RFC822_TIMEZONE_FIELD:
		buffer.setDefaultAttribute(DateFormat.Field.RFC822_TIME_ZONE);
		int pureMinutes = (calendar.get(Calendar.ZONE_OFFSET) +
				   calendar.get(Calendar.DST_OFFSET)) / (1000 * 60);
		String sign = (pureMinutes < 0) ? "-" : "+";	  
		int hours = pureMinutes / 60;
		int minutes = pureMinutes % 60;
		buffer.append(sign);
		withLeadingZeros(hours, 2, buffer);
		withLeadingZeros(minutes, 2, buffer);
		break;
	      default:
		throw new IllegalArgumentException ("Illegal pattern character " +
						    cf.getCharacter());
	      }
	    if (pos != null && (buffer.getDefaultAttribute() == pos.getFieldAttribute()
				|| cf.getField() == pos.getField()))
	      {
		pos.setBeginIndex(beginIndex);
		pos.setEndIndex(buffer.length());
	      }
	  } 
      else
	{  
	  buffer.append(o.toString(), null);
	}
      }
  }
  
  public StringBuffer format(Date date, StringBuffer buffer, FieldPosition pos)
  {
    formatWithAttribute(date, new StringFormatBuffer (buffer), pos);

    return buffer;
  }

  public AttributedCharacterIterator formatToCharacterIterator(Object date)
    throws IllegalArgumentException
  {
    if (date == null)
      throw new NullPointerException("null argument");
    if (!(date instanceof Date))
      throw new IllegalArgumentException("argument should be an instance of java.util.Date");

    AttributedFormatBuffer buf = new AttributedFormatBuffer();
    formatWithAttribute((Date)date, buf,
			null);
    buf.sync();
        
    return new FormatCharacterIterator(buf.getBuffer().toString(),
				       buf.getRanges(),
				       buf.getAttributes());
  }

  private void withLeadingZeros(int value, int length, FormatBuffer buffer)