exsltdatetime.java

java1.6众多例子参考

     * of the week of a date. If no argument is given, then the current local 
     * date/time, as returned  by date:date-time is used the default argument. 
     * The date/time string specified as the argument is a left or right-truncated 
     * string in the format defined as the lexical representation of xs:dateTime 
     * in one of the formats defined in 
     * <a href="http://www.w3.org/TR/xmlschema-2/">[XML Schema Part 2: Datatypes]</a>. 
     * The permitted formats are as follows: 
     *     xs:dateTime (CCYY-MM-DDThh:mm:ss) 
     *     xs:date (CCYY-MM-DD) 
     * If the date/time string is not in one of these formats, then the empty string 
     * ('') is returned. 
     * The result is a three-letter English day abbreviation: one of 'Sun', 'Mon', 'Tue', 
     * 'Wed', 'Thu' or 'Fri'. 
     * An implementation of this extension function in the EXSLT date namespace must conform 
     * to the behaviour described in this document. 
     */
    public static String dayAbbreviation(String datetimeIn)
      throws ParseException
    {
      String[] edz = getEraDatetimeZone(datetimeIn);
      String datetime = edz[1];
      if (datetime == null) 
        return EMPTY_STR;            
      
      String[] formatsIn = {dt, d};
      String formatOut = "EEE";
      return getNameOrAbbrev(datetimeIn, formatsIn, formatOut);
    }
    
    /**
     * See above.
     */
    public static String dayAbbreviation()
    {
      String format = "EEE";
      return getNameOrAbbrev(format);              
    }
    
    /**
     * Returns an array with the 3 components that a datetime input string 
     * may contain: - (for BC era), datetime, and zone. If the zone is not
     * valid, return null for that component.
     */
    private static String[] getEraDatetimeZone(String in)
    {
      String leader = "";
      String datetime = in;
      String zone = "";
      if (in.charAt(0)=='-' && !in.startsWith("--"))
      {
        leader = "-"; //  '+' is implicit , not allowed
        datetime = in.substring(1);
      }
      int z = getZoneStart(datetime);
      if (z > 0)
      {
        zone = datetime.substring(z);
        datetime = datetime.substring(0, z);
      }
      else if (z == -2)
        zone = null;
      //System.out.println("'" + leader + "' " + datetime + " " + zone);
      return new String[]{leader, datetime, zone};  
    }    
    
    /**
     * Get the start of zone information if the input ends
     * with 'Z' or +/-hh:mm. If a zone string is not
     * found, return -1; if the zone string is invalid,
     * return -2.
     */
    private static int getZoneStart (String datetime)
    {
      if (datetime.indexOf("Z") == datetime.length()-1)
        return datetime.length()-1;
      else if (datetime.length() >=6 
      		&& datetime.charAt(datetime.length()-3) == ':'
      		&& (datetime.charAt(datetime.length()-6) == '+' 
      		    || datetime.charAt(datetime.length()-6) == '-'))      		    
      {
        try
        {
          SimpleDateFormat dateFormat = new SimpleDateFormat("HH:mm");
          dateFormat.setLenient(false);
          Date d = dateFormat.parse(datetime.substring(datetime.length() -5));
          return datetime.length()-6;
        }
        catch (ParseException pe)
        {
          System.out.println("ParseException " + pe.getErrorOffset());
          return -2; // Invalid.
        }

      }
        return -1; // No zone information.
    }
    
    /**
     * Attempt to parse an input string with the allowed formats, returning
     * null if none of the formats work.
     */
    private static Date testFormats (String in, String[] formats)
      throws ParseException
    {
      for (int i = 0; i <formats.length; i++)
      {
        try
        {
          SimpleDateFormat dateFormat = new SimpleDateFormat(formats[i]);
          dateFormat.setLenient(false);          
          return dateFormat.parse(in);
        }
        catch (ParseException pe)
        {
        }
      }
      return null;
    }
    
    
    /**
     * Parse the input string and return the corresponding calendar field
     * number.
     */
    private static double getNumber(String in, String[] formats, int calField)
      throws ParseException
    {
      Calendar cal = Calendar.getInstance();
      cal.setLenient(false);
      // Try the allowed formats, from longest to shortest.
      Date date = testFormats(in, formats);
      if (date == null) return Double.NaN;
      cal.setTime(date);
      return cal.get(calField);
    }    
     
    /**
     *  Get the full name or abbreviation of the month or day.
     */
    private static String getNameOrAbbrev(String in, 
                                         String[] formatsIn,
                                         String formatOut)
      throws ParseException
    {
      for (int i = 0; i <formatsIn.length; i++) // from longest to shortest.
      {
        try
        {
          SimpleDateFormat dateFormat = new SimpleDateFormat(formatsIn[i], Locale.ENGLISH);
          dateFormat.setLenient(false);
          Date dt = dateFormat.parse(in);          
          dateFormat.applyPattern(formatOut);
          return dateFormat.format(dt);
        }
        catch (ParseException pe)
        {
        }
      }
      return "";
    }
    /**
     * Get the full name or abbreviation for the current month or day 
     * (no input string).
     */
    private static String getNameOrAbbrev(String format)
    {
      Calendar cal = Calendar.getInstance();
      SimpleDateFormat dateFormat = new SimpleDateFormat(format, Locale.ENGLISH);
      return dateFormat.format(cal.getTime());
    }

    /**
     * The date:format-date function formats a date/time according to a pattern.
     * <p>
     * The first argument to date:format-date specifies the date/time to be 
     * formatted. It must be right or left-truncated date/time strings in one of 
     * the formats defined in 
     * <a href="http://www.w3.org/TR/xmlschema-2/">[XML Schema Part 2: Datatypes]</a>. 
     * The permitted formats are as follows: 
     * <ul>
     * <li>xs:dateTime (CCYY-MM-DDThh:mm:ss) 
     * <li>xs:date (CCYY-MM-DD) 
     * <li>xs:time (hh:mm:ss) 
     * <li>xs:gYearMonth (CCYY-MM) 
     * <li>xs:gYear (CCYY) 
     * <li>xs:gMonthDay (--MM-DD) 
     * <li>xs:gMonth (--MM--) 
     * <li>xs:gDay (---DD)
     * </ul>
     * The second argument is a string that gives the format pattern used to 
     * format the date. The format pattern must be in the syntax specified by 
     * the JDK 1.1 SimpleDateFormat class. The format pattern string is 
     * interpreted as described for the JDK 1.1 SimpleDateFormat class. 
     * <p>
     * If the date/time format is right-truncated (i.e. in a format other than 
     * xs:time, or xs:dateTime) then any missing components are assumed to be as 
     * follows: if no month is specified, it is given a month of 01; if no day 
     * is specified, it is given a day of 01; if no time is specified, it is 
     * given a time of 00:00:00. 
     * <p>
     * If the date/time format is left-truncated (i.e. xs:time, xs:gMonthDay, 
     * xs:gMonth or xs:gDay) and the format pattern has a token that uses a 
     * component that is missing from the date/time format used, then that token 
     * is replaced with an empty string ('') within the result.
     * 
     * The author is Helg Bredow ([e-mail])
     */
    public static String formatDate(String dateTime, String pattern)
    {
        final String yearSymbols = "Gy";
        final String monthSymbols = "M";
        final String daySymbols = "dDEFwW";
        TimeZone timeZone;
        String zone;

        // Get the timezone information if it was supplied and modify the 
        // dateTime so that SimpleDateFormat will understand it.
        if (dateTime.endsWith("Z") || dateTime.endsWith("z"))
        {
            timeZone = TimeZone.getTimeZone("GMT");
            dateTime = dateTime.substring(0, dateTime.length()-1) + "GMT";
            zone = "z";
        }
        else if ((dateTime.length() >= 6) 
                 && (dateTime.charAt(dateTime.length()-3) == ':') 
                 && ((dateTime.charAt(dateTime.length()-6) == '+') 
                    || (dateTime.charAt(dateTime.length()-6) == '-')))
        {
            String offset = dateTime.substring(dateTime.length()-6);
            
            if ("+00:00".equals(offset) || "-00:00".equals(offset))
            {
                timeZone = TimeZone.getTimeZone("GMT");
            }
            else
            {
                timeZone = TimeZone.getTimeZone("GMT" + offset);
            }
            zone = "z";
            // Need to adjust it since SimpleDateFormat requires GMT+hh:mm but
            // we have +hh:mm.
            dateTime = dateTime.substring(0, dateTime.length()-6) + "GMT" + offset;
        }
        else
        {
            // Assume local time.
            timeZone = TimeZone.getDefault();
            zone = "";
            // Leave off the timezone since SimpleDateFormat will assume local
            // time if time zone is not included.
        }
        String[] formats = {dt + zone, d, gym, gy};
        
        // Try the time format first. We need to do this to prevent 
        // SimpleDateFormat from interpreting a time as a year. i.e we just need
        // to check if it's a time before we check it's a year.
        try
        {
            SimpleDateFormat inFormat = new SimpleDateFormat(t + zone);
            inFormat.setLenient(false);
            Date d= inFormat.parse(dateTime);
            SimpleDateFormat outFormat = new SimpleDateFormat(strip
                (yearSymbols + monthSymbols + daySymbols, pattern));
            outFormat.setTimeZone(timeZone);
            return outFormat.format(d);
        }
        catch (ParseException pe)
        {
        }
        
        // Try the right truncated formats.
        for (int i = 0; i < formats.length; i++)
        {
            try
            {
                SimpleDateFormat inFormat = new SimpleDateFormat(formats[i]);
                inFormat.setLenient(false);
                Date d = inFormat.parse(dateTime);
                SimpleDateFormat outFormat = new SimpleDateFormat(pattern);
                outFormat.setTimeZone(timeZone);
                return outFormat.format(d);
            }
            catch (ParseException pe)
            {
            }
        }
        
        // Now try the left truncated ones. The Java format() function doesn't
        // return the correct strings in this case. We strip any pattern 
        // symbols that shouldn't be output so that they are not defaulted to 
        // inappropriate values in the output.
        try
        {
            SimpleDateFormat inFormat = new SimpleDateFormat(gmd);
            inFormat.setLenient(false);          
            Date d = inFormat.parse(dateTime);
            SimpleDateFormat outFormat = new SimpleDateFormat(strip(yearSymbols, pattern));
            outFormat.setTimeZone(timeZone);
            return outFormat.format(d);
        }
        catch (ParseException pe)
        {
        }
        try
        {
            SimpleDateFormat inFormat = new SimpleDateFormat(gm);
            inFormat.setLenient(false);
            Date d = inFormat.parse(dateTime);
            SimpleDateFormat outFormat = new SimpleDateFormat(strip(yearSymbols, pattern));
            outFormat.setTimeZone(timeZone);
            return outFormat.format(d);
        }
        catch (ParseException pe)
        {
        }
        try
        {
            SimpleDateFormat inFormat = new SimpleDateFormat(gd);
            inFormat.setLenient(false);
            Date d = inFormat.parse(dateTime);
            SimpleDateFormat outFormat = new SimpleDateFormat(strip(yearSymbols + monthSymbols, pattern));
            outFormat.setTimeZone(timeZone);
            return outFormat.format(d);
        }
        catch (ParseException pe)
        {
        }
        return EMPTY_STR;
    }
    
    /**
     * Strips occurrences of the given character from a date format pattern.
     * @param symbols list of symbols to strip.
     * @param pattern
     * @return
     */
    private static String strip(String symbols, String pattern)
    {
        int quoteSemaphore = 0;
        int i = 0;
        StringBuffer result = new StringBuffer(pattern.length());

        while (i < pattern.length())
        {
            char ch = pattern.charAt(i);
            if (ch == '\'')
            {
                // Assume it's an openening quote so simply copy the quoted 
                // text to the result. There is nothing to strip here.
                int endQuote = pattern.indexOf('\'', i + 1);
                if (endQuote == -1)
                {
                    endQuote = pattern.length();
                }
                result.append(pattern.substring(i, endQuote));
                i = endQuote++;
            }
            else if (symbols.indexOf(ch) > -1)
            {
                // The char needs to be stripped.
                i++;
            }
            else
            {
                result.append(ch);
                i++;
            }
        }
        return result.toString();
    }

}