Date parser for ISO 8601 format : Date Parser « Data Type « Java

1. Java
2. Data Type
3. Date Parser

Date parser for ISO 8601 format

     
// DateParser.java
// $Id: DateParser.java,v 1.5 2005/05/16 10:19:19 ylafon Exp $
// (c) COPYRIGHT MIT, INRIA and Keio, 2000.
// Please first read the full copyright statement in file COPYRIGHT.html

import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.NoSuchElementException;
import java.util.StringTokenizer;
import java.util.TimeZone;

/**
 * Date parser for ISO 8601 format
 * http://www.w3.org/TR/1998/NOTE-datetime-19980827
 * 
 * @version $Revision: 1.5 $
 * @author Benot Mah (bmahe@w3.org)
 * @author Yves Lafon (ylafon@w3.org)
 */
public class DateParser {

  private static boolean check(StringTokenizer st, String token)

  {
    try {
      if (st.nextToken().equals(token)) {
        return true;
      } else {
        throw new RuntimeException("Missing [" + token + "]");
      }
    } catch (NoSuchElementException ex) {
      return false;
    }
  }

  private static Calendar getCalendar(String isodate) {
    // YYYY-MM-DDThh:mm:ss.sTZD
    StringTokenizer st = new StringTokenizer(isodate, "-T:.+Z", true);

    Calendar calendar = new GregorianCalendar(TimeZone.getTimeZone("UTC"));
    calendar.clear();
    try {
      // Year
      if (st.hasMoreTokens()) {
        int year = Integer.parseInt(st.nextToken());
        calendar.set(Calendar.YEAR, year);
      } else {
        return calendar;
      }
      // Month
      if (check(st, "-") && (st.hasMoreTokens())) {
        int month = Integer.parseInt(st.nextToken()) - 1;
        calendar.set(Calendar.MONTH, month);
      } else {
        return calendar;
      }
      // Day
      if (check(st, "-") && (st.hasMoreTokens())) {
        int day = Integer.parseInt(st.nextToken());
        calendar.set(Calendar.DAY_OF_MONTH, day);
      } else {
        return calendar;
      }
      // Hour
      if (check(st, "T") && (st.hasMoreTokens())) {
        int hour = Integer.parseInt(st.nextToken());
        calendar.set(Calendar.HOUR_OF_DAY, hour);
      } else {
        calendar.set(Calendar.HOUR_OF_DAY, 0);
        calendar.set(Calendar.MINUTE, 0);
        calendar.set(Calendar.SECOND, 0);
        calendar.set(Calendar.MILLISECOND, 0);
        return calendar;
      }
      // Minutes
      if (check(st, ":") && (st.hasMoreTokens())) {
        int minutes = Integer.parseInt(st.nextToken());
        calendar.set(Calendar.MINUTE, minutes);
      } else {
        calendar.set(Calendar.MINUTE, 0);
        calendar.set(Calendar.SECOND, 0);
        calendar.set(Calendar.MILLISECOND, 0);
        return calendar;
      }

      //
      // Not mandatory now
      //

      // Secondes
      if (!st.hasMoreTokens()) {
        return calendar;
      }
      String tok = st.nextToken();
      if (tok.equals(":")) { // secondes
        if (st.hasMoreTokens()) {
          int secondes = Integer.parseInt(st.nextToken());
          calendar.set(Calendar.SECOND, secondes);
          if (!st.hasMoreTokens()) {
            return calendar;
          }
          // frac sec
          tok = st.nextToken();
          if (tok.equals(".")) {
            // bug fixed, thx to Martin Bottcher
            String nt = st.nextToken();
            while (nt.length() < 3) {
              nt += "0";
            }
            nt = nt.substring(0, 3); // Cut trailing chars..
            int millisec = Integer.parseInt(nt);
            // int millisec = Integer.parseInt(st.nextToken()) * 10;
            calendar.set(Calendar.MILLISECOND, millisec);
            if (!st.hasMoreTokens()) {
              return calendar;
            }
            tok = st.nextToken();
          } else {
            calendar.set(Calendar.MILLISECOND, 0);
          }
        } else {
          throw new RuntimeException("No secondes specified");
        }
      } else {
        calendar.set(Calendar.SECOND, 0);
        calendar.set(Calendar.MILLISECOND, 0);
      }
      // Timezone
      if (!tok.equals("Z")) { // UTC
        if (!(tok.equals("+") || tok.equals("-"))) {
          throw new RuntimeException("only Z, + or - allowed");
        }
        boolean plus = tok.equals("+");
        if (!st.hasMoreTokens()) {
          throw new RuntimeException("Missing hour field");
        }
        int tzhour = Integer.parseInt(st.nextToken());
        int tzmin = 0;
        if (check(st, ":") && (st.hasMoreTokens())) {
          tzmin = Integer.parseInt(st.nextToken());
        } else {
          throw new RuntimeException("Missing minute field");
        }
        if (plus) {
          calendar.add(Calendar.HOUR, -tzhour);
          calendar.add(Calendar.MINUTE, -tzmin);
        } else {
          calendar.add(Calendar.HOUR, tzhour);
          calendar.add(Calendar.MINUTE, tzmin);
        }
      }
    } catch (NumberFormatException ex) {
      throw new RuntimeException("[" + ex.getMessage() + "] is not an integer");
    }
    return calendar;
  }

  /**
   * Parse the given string in ISO 8601 format and build a Date object.
   * 
   * @param isodate
   *          the date in ISO 8601 format
   * @return a Date instance
   * @exception InvalidDateException
   *              if the date is not valid
   */
  public static Date parse(String isodate) {
    Calendar calendar = getCalendar(isodate);
    return calendar.getTime();
  }

  private static String twoDigit(int i) {
    if (i >= 0 && i < 10) {
      return "0" + String.valueOf(i);
    }
    return String.valueOf(i);
  }

  /**
   * Generate a ISO 8601 date
   * 
   * @param date
   *          a Date instance
   * @return a string representing the date in the ISO 8601 format
   */
  public static String getIsoDate(Date date) {
    Calendar calendar = new GregorianCalendar(TimeZone.getTimeZone("UTC"));
    calendar.setTime(date);
    StringBuffer buffer = new StringBuffer();
    buffer.append(calendar.get(Calendar.YEAR));
    buffer.append("-");
    buffer.append(twoDigit(calendar.get(Calendar.MONTH) + 1));
    buffer.append("-");
    buffer.append(twoDigit(calendar.get(Calendar.DAY_OF_MONTH)));
    buffer.append("T");
    buffer.append(twoDigit(calendar.get(Calendar.HOUR_OF_DAY)));
    buffer.append(":");
    buffer.append(twoDigit(calendar.get(Calendar.MINUTE)));
    buffer.append(":");
    buffer.append(twoDigit(calendar.get(Calendar.SECOND)));
    buffer.append(".");
    buffer.append(twoDigit(calendar.get(Calendar.MILLISECOND) / 10));
    buffer.append("Z");
    return buffer.toString();
  }

  /**
   * Generate a ISO 8601 date
   * 
   * @param date
   *          a Date instance
   * @return a string representing the date in the ISO 8601 format
   */
  public static String getIsoDateNoMillis(Date date) {
    Calendar calendar = new GregorianCalendar(TimeZone.getTimeZone("UTC"));
    calendar.setTime(date);
    StringBuffer buffer = new StringBuffer();
    buffer.append(calendar.get(Calendar.YEAR));
    buffer.append("-");
    buffer.append(twoDigit(calendar.get(Calendar.MONTH) + 1));
    buffer.append("-");
    buffer.append(twoDigit(calendar.get(Calendar.DAY_OF_MONTH)));
    buffer.append("T");
    buffer.append(twoDigit(calendar.get(Calendar.HOUR_OF_DAY)));
    buffer.append(":");
    buffer.append(twoDigit(calendar.get(Calendar.MINUTE)));
    buffer.append(":");
    buffer.append(twoDigit(calendar.get(Calendar.SECOND)));
    buffer.append("Z");
    return buffer.toString();
  }

  public static void test(String isodate) {
    System.out.println("----------------------------------");
    Date date = parse(isodate);
    System.out.println(">> " + isodate);
    System.out.println(">> " + date.toString() + " [" + date.getTime() + "]");
    System.out.println(">> " + getIsoDate(date));
    System.out.println("----------------------------------");
  }

  public static void test(Date date) {
    String isodate = null;
    System.out.println("----------------------------------");
    System.out.println(">> " + date.toString() + " [" + date.getTime() + "]");
    isodate = getIsoDate(date);
    System.out.println(">> " + isodate);
    date = parse(isodate);
    System.out.println(">> " + date.toString() + " [" + date.getTime() + "]");
    System.out.println("----------------------------------");
  }

  public static void main(String args[]) {
    test("1997-07-16T19:20:30.45-02:00");
    test("1997-07-16T19:20:30+01:00");
    test("1997-07-16T19:20:30+01:00");
    test("1997-07-16T12:20:30-06:00");
    test("1997-07-16T19:20");
    test("1997-07-16");
    test("1997-07");
    test("1997");
    test(new Date());
  }

}

   
    
    
    
    
  

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