/* ======================================================================
The Bodington System Software License, Version 1.0
  
Copyright (c) 2001 The University of Leeds.  All rights reserved.
  
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

1.  Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.

2.  Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.

3.  The end-user documentation included with the redistribution, if any,
must include the following acknowledgement:  "This product includes
software developed by the University of Leeds
(http://www.bodington.org/)."  Alternately, this acknowledgement may
appear in the software itself, if and wherever such third-party
acknowledgements normally appear.

4.  The names "Bodington", "Nathan Bodington", "Bodington System",
"Bodington Open Source Project", and "The University of Leeds" must not be
used to endorse or promote products derived from this software without
prior written permission. For written permission, please contact
d.gardner@leeds.ac.uk.

5.  The name "Bodington" may not appear in the name of products derived
from this software without prior written permission of the University of
Leeds.

THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO,  TITLE,  THE IMPLIED WARRANTIES 
OF QUALITY  AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO 
EVENT SHALL THE UNIVERSITY OF LEEDS OR ITS CONTRIBUTORS BE LIABLE FOR 
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE 
GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 
STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
POSSIBILITY OF SUCH DAMAGE.
=========================================================

This software was originally created by the University of Leeds and may contain voluntary 
contributions from others.  For more information on the Bodington Open Source Project, please 
see http://bodington.org/

====================================================================== */

package org.bodington.servlet;

import org.apache.log4j.Logger;

import java.util.*;
import java.text.*;

/**
 * Utility class for parsing strings into dates.
 * @see Date
 * @see java.text.SimpleDateFormat
 * @author Jon Maber
 * @author Antony Corfield
 */
public class DateParser extends java.lang.Object
	{
    
    private static Logger log = Logger.getLogger(DateParser.class);
    
    static final String fixed_date_time="dd/MM/yy HH:mm";
	
	static final String[] day_patterns={"d", "d'st'", "d'nd'", "d'rd'", "d'th'"};
	static final String[] month_patterns={"M", "MM", "MMM", "MMMMM"};
	//static final String[] year_patterns={"yyyy", "yy" };
	static final String[] year_patterns={"yyyy"};
	static final String[] sep_patterns={ " ", "/", "\\", "-", ":", ";", ",", "." };

	public static java.util.Date parse( String d )
		{
		SimpleDateFormat sdf;
		java.util.Date dob;
		String pattern;
		int i, j, k, m;
	
		for ( i=0; i<day_patterns.length; i++ )
			for ( j=0; j<sep_patterns.length; j++ )
				for ( k=0; k<month_patterns.length; k++ )
					for ( m=0; m<year_patterns.length; m++ )
			{
			if ( sep_patterns[j].length()==0 && month_patterns[k].length()<2 )
				continue;
				
			pattern=day_patterns[i]+sep_patterns[j]+month_patterns[k]+sep_patterns[j]+year_patterns[m];

			sdf=new SimpleDateFormat( pattern );
			log.debug( sdf.toPattern() );
			sdf.setLenient( true );
		
			try 
				{
				dob=sdf.parse( d );
				if ( dob!=null )
					return dob;
				}
			catch ( Exception ex )
				{
				//go round and try another format;
				}
			}

		log.debug( "unparsable date" );
		
		return null;
		}
	
   /**
     * Parses the specified string as a date. This will be formatted according
     * to the <code>format</code> parameter.
     * @param date the String date to be parsed.
     * @param format the format of the date to be parsed.
     * @return the specified string as a date.
     * @see java.util.Date
     * @see java.text.SimpleDateFormat
     */
    public static java.util.Date parseDateAndTime( String date, String format )
    {
        SimpleDateFormat sdf = new SimpleDateFormat( format );
        java.util.Date dob;
        log.debug( sdf.toPattern() );
        sdf.setLenient( true );

        try
        {
            dob = sdf.parse( date );
            if ( dob != null ) return dob;
        }
        catch ( Exception ex )
        {
            log.debug( "unparsable date" );
        }
        return null;
    }

    /**
     * Parses the specified string as a date. This version of the method expects
     * the string to be in the following format:
     * <p>
     * <code>dd/MM/yy HH:mm</code>.
     * @param date the String date to be parsed.
     * @return the specified string as a date.
     * @see #parseDateAndTime( String date, String format)
     */
    public static java.util.Date parseDateAndTime( String date )
    {
        return parseDateAndTime( date, fixed_date_time );
    }
	}