date.java

The program is used for the calculations of the day , week , month on the calendar .

package us.k5n.ical;


import java.util.Calendar;


/**
  * Base class for use with a variety of date-related iCal fields
  * including LAST-MODIFIED, DTSTAMP, DTSTART, etc.
  * This can represent both a date and a date-time.
  * @version $Id$
  * @author Craig Knudsen, [e-mail]
  */
public class Date extends Property
  implements Constants
{
  int year, month, day;
  int hour, minute, second;
  boolean isUTC = false;
  boolean dateOnly = false; // is date only (rather than date-time)?

  /**
    * Constructor
    * @param icalStr	One or more lines of iCal that specifies
    *			a date.  Dates must be of one of the following
    *			formats: <ul>
    *			<li>  19991231 (date only, no time) </li>
    *			<li>  19991231T115900 (date with local time) </li>
    *			<li>  19991231T115900Z (date and time UTC) </li>
    *			</ul>
    *			(This format is a based on the ISO 8601 standard.)
    */
  public Date ( String icalStr )
    throws ParseException, BogusDataException
  {
    this ( icalStr, PARSE_LOOSE );
  }


  /**
    * Constructor: create a date based on the specified year, month and day.
    * @param dateType	Type of date; this should be an ical property name
    *			like DTSTART, DTEND or DTSTAMP.
    * @param year	The 4-digit year
    * @param month	The month (1-12)
    * @param day	The day of the month (1-31)
    */
    
  public Date ( String dateType, int year, int month, int day )
    throws ParseException, BogusDataException
  {
    super ( dateType, "" );

    this.year = year;
    this.month = month;
    this.day = day;
    hour = minute = second = 0;
    dateOnly = true;

    String yearStr, monthStr, dayStr;

    yearStr = "" + year;
    monthStr = "" + month;
    dayStr = "" + day;
    while ( yearStr.length() < 4 )
      yearStr = '0' + yearStr;
    if ( monthStr.length() < 2 )
      monthStr = '0' + monthStr;
    if ( dayStr.length() < 2 )
      dayStr = '0' + dayStr;
    value = yearStr + monthStr + dayStr;

    // Add attribute that says date-only
    addAttribute ( "VALUE", "DATE" );
  }


  /**
    * Constructor
    * @param icalStr	One or more lines of iCal that specifies
    *			a date
    * @param parseMode	PARSE_STRICT or PARSE_LOOSE
    */
  public Date ( String icalStr, int parseMode )
    throws ParseException, BogusDataException
  {
    super ( icalStr, parseMode );

    year = month = day = 0;
    hour = minute = second = 0;

    for ( int i = 0; i < attributeList.size(); i++ ) {
      Attribute a = attributeAt ( i );
      String aname = a.name.toUpperCase();
      String aval = a.value.toUpperCase();
      // TODO: not sure if any attributes are allowed here...
      // Look for VALUE=DATE or VALUE=DATE-TIME
      // DATE means untimed for the event
      if ( aname.equals ( "VALUE" ) ) {
        if ( aval.equals ( "DATE" ) ) {
          dateOnly = true;
        } else if ( aval.equals ( "DATE-TIME" ) ) {
          dateOnly = false;
        } else {
          if ( parseMode == PARSE_STRICT ) {
            throw new ParseException ( "Unknown date VALUE '" + a.value + "'",
              icalStr );
          }
        }
      } else {
        // TODO: anything else allowed here?
      }
    }

    String inDate = value;

    if ( inDate.length() < 8 ) {
      // Invalid format
      throw new ParseException ( "Invalid date format '" + inDate + "'",
        inDate );
    }

    year = Integer.parseInt ( inDate.substring ( 0, 4 ) );
    month = Integer.parseInt ( inDate.substring ( 4, 6 ) );
    day = Integer.parseInt ( inDate.substring ( 6, 8 ) );
    // TODO: validate for each month and leap years, too
    if ( day < 1 || day > 31 || month < 1 || month > 12 )
      throw new BogusDataException ( "Invalid date '" + inDate + "'", inDate );
    // TODO: parse time, handle localtime, handle timezone
    if ( inDate.length() > 8 ) {
      // TODO make sure dateOnly == false
      if ( inDate.charAt ( 8 ) == 'T' ) {
        try {
          hour = Integer.parseInt ( inDate.substring ( 9, 11 ) );
          minute = Integer.parseInt ( inDate.substring ( 11, 13 ) );
          second = Integer.parseInt ( inDate.substring ( 13, 15 ) );
          if ( hour > 23 || minute > 59 || second > 59 ) {
            throw new BogusDataException ( "Invalid time in date string '" +
              inDate + "'", inDate );
          }
          if ( inDate.length() >= 15 ) {
            isUTC = inDate.charAt ( 15 ) == 'Z';
          }
        } catch ( NumberFormatException nef ) {
          throw new BogusDataException ( "Invalid time in date string '" +
            inDate + "' - " + nef, inDate );
        }
      } else {
        // Invalid format
        throw new ParseException ( "Invalid date format '" + inDate + "'",
          inDate );
      }
    } else {
      // Just date, no time
    }
  }

  /**
    * Does the date contain a time components?
    * @return	true if the Date contains a time components
    */
  public boolean hasTime ()
  {
    return ( ! dateOnly );
  }


  /**
    * Generate the iCal string for this Date.
    */
  public String toIcal ()
  {
    StringBuffer sb = new StringBuffer ( dateOnly ? 8 : 15 );
    sb.append ( year );
    if ( month < 10 )
      sb.append ( '0' );
    sb.append ( month );
    if ( day < 10 )
      sb.append ( '0' );
    sb.append ( day );

    if ( ! dateOnly ) {
      sb.append ( 'T' );
      if ( hour < 10 )
        sb.append ( '0' );
      sb.append ( hour );
      if ( minute < 10 )
        sb.append ( '0' );
      sb.append ( minute );
      if ( second < 10 )
        sb.append ( '0' );
      sb.append ( second );
      if ( isUTC )
        sb.append ( 'Z' );
    }
    value = sb.toString ();
    return super.toIcal ();
  }

  // Test routine - will parse input string and then export back
  // into ical format.
  // Usage: java Date "DTSTAMP;20030701T000000Z"
  //   
  public static void main ( String args[] )
  {
    for ( int i = 0; i < args.length; i++ ) {
      try {
        java.io.File f = new java.io.File ( args[i] );
        Date a = null;
        String input = null;
        if ( f.exists () ) {
          try {
            input = Utils.getFileContents ( f );
          } catch ( Exception e ) {
            System.err.println ( "Error opening " + f + ": " + e );
            System.exit ( 1 );
          }
        } else {
          input = args[i];
        }
        a = new Date ( input, PARSE_STRICT );
        System.out.println ( "Date input:\n  " + args[i] );
        System.out.println ( "\nDate text:\n" + a.value );
        System.out.println ( "\nDate output:\n  " + a.toIcal () );
      } catch ( ParseException e ) {
        System.err.println ( "iCal Parse Exception: " + e );
      } catch ( BogusDataException e2 ) {
        System.err.println ( "iCal Data Exception: " + e2 );
      }
    }
  }

}