/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.jempbox.impl;
import java.io.IOException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.SimpleTimeZone;
/**
* This class is used to convert dates to strings and back using the PDF
* date standards. Date are described in PDFReference1.4 section 3.8.2
*
* @author <a href="mailto:ben@benlitchfield.com">Ben Litchfield</a>
* @author <a href="mailto:chris@oezbek.net">Christopher Oezbek</a>
*
* @version $Revision: 1.6 $
*/
public class DateConverter
{
//The Date format is supposed to be the PDF_DATE_FORMAT, but not all PDF documents
//will use that date, so I have added a couple other potential formats
//to try if the original one does not work.
private static final SimpleDateFormat[] POTENTIAL_FORMATS = new SimpleDateFormat[] {
new SimpleDateFormat("EEEE, dd MMM yyyy hh:mm:ss a"),
new SimpleDateFormat("EEEE, MMM dd, yyyy hh:mm:ss a"),
new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'"),
new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssz")};
private DateConverter()
{
//utility class should not be constructed.
}
/**
* This will convert a string to a calendar.
*
* @param date The string representation of the calendar.
*
* @return The calendar that this string represents.
*
* @throws IOException If the date string is not in the correct format.
*/
public static Calendar toCalendar( String date ) throws IOException
{
Calendar retval = null;
if( date != null && date.trim().length() > 0 )
{
//these are the default values
int year = 0;
int month = 1;
int day = 1;
int hour = 0;
int minute = 0;
int second = 0;
//first string off the prefix if it exists
try
{
SimpleTimeZone zone = null;
if( date.startsWith( "D:" ) )
{
date = date.substring( 2, date.length() );
}
date = date.replaceAll("[-:T]", "");
if( date.length() < 4 )
{
throw new IOException( "Error: Invalid date format '" + date + "'" );
}
year = Integer.parseInt( date.substring( 0, 4 ) );
if( date.length() >= 6 )
{
month = Integer.parseInt( date.substring( 4, 6 ) );
}
if( date.length() >= 8 )
{
day = Integer.parseInt( date.substring( 6, 8 ) );
}
if( date.length() >= 10 )
{
hour = Integer.parseInt( date.substring( 8, 10 ) );
}
if( date.length() >= 12 )
{
minute = Integer.parseInt( date.substring( 10, 12 ) );
}
if( date.length() >= 14 )
{
second = Integer.parseInt( date.substring( 12, 14 ) );
}
if( date.length() >= 15 )
{
char sign = date.charAt( 14 );
if( sign == 'Z' )
{
zone = new SimpleTimeZone(0,"Unknown");
}
else
{
int hours = 0;
int minutes = 0;
if( date.length() >= 17 )
{
if( sign == '+' )
{
//parseInt cannot handle the + sign
hours = Integer.parseInt( date.substring( 15, 17 ) );
}
else
{
hours = -Integer.parseInt( date.substring( 14, 16 ) );
}
}
if( sign=='+' )
{
if( date.length() >= 19 )
{
minutes = Integer.parseInt( date.substring( 17, 19 ) );
}
}
else
{
if( date.length() >= 18 )
{
minutes = Integer.parseInt( date.substring( 16, 18 ) );
}
}
zone = new SimpleTimeZone( hours*60*60*1000 + minutes*60*1000, "Unknown" );
}
}
if( zone == null )
{
retval = new GregorianCalendar();
}
else
{
retval = new GregorianCalendar( zone );
}
retval.clear();
retval.set( year, month-1, day, hour, minute, second );
}
catch( NumberFormatException e )
{
// remove the arbitrary : in the timezone. SimpleDateFormat
// can't handle it
if (date.substring(date.length()-3,date.length()-2).equals(":") &&
(date.substring(date.length()-6,date.length()-5).equals("+") ||
date.substring(date.length()-6,date.length()-5).equals("-")))
{
//thats a timezone string, remove the :
date = date.substring(0,date.length()-3) +
date.substring(date.length()-2);
}
for( int i=0; retval == null && i<POTENTIAL_FORMATS.length; i++ )
{
try
{
Date utilDate = POTENTIAL_FORMATS[i].parse( date );
retval = new GregorianCalendar();
retval.setTime( utilDate );
}
catch( ParseException pe )
{
//ignore and move to next potential format
}
}
if( retval == null )
{
//we didn't find a valid date format so throw an exception
throw new IOException( "Error converting date:" + date );
}
}
}
return retval;
}
private static final void zeroAppend( StringBuffer out, int number )
{
if( number < 10 )
{
out.append( "0" );
}
out.append( number );
}
/**
* Convert the date to iso 8601 string format.
*
* @param cal The date to convert.
* @return The date represented as an ISO 8601 string.
*/
public static String toISO8601( Calendar cal )
{
StringBuffer retval = new StringBuffer();
retval.append( cal.get( Calendar.YEAR ) );
retval.append( "-" );
zeroAppend( retval, cal.get( Calendar.MONTH )+1 );
retval.append( "-" );
zeroAppend( retval, cal.get( Calendar.DAY_OF_MONTH ) );
retval.append( "T" );
zeroAppend( retval, cal.get( Calendar.HOUR_OF_DAY ));
retval.append( ":" );
zeroAppend( retval, cal.get( Calendar.MINUTE ));
retval.append( ":" );
zeroAppend( retval, cal.get( Calendar.SECOND ));
int timeZone = cal.get( Calendar.ZONE_OFFSET ) + cal.get(Calendar.DST_OFFSET );
if( timeZone < 0 )
{
retval.append( "-" );
}
else
{
retval.append( "+" );
}
timeZone = Math.abs( timeZone );
//milliseconds/1000 = seconds = seconds / 60 = minutes = minutes/60 = hours
int hours = timeZone/1000/60/60;
int minutes = (timeZone - (hours*1000*60*60))/1000/1000;
if( hours < 10 )
{
retval.append( "0" );
}
retval.append( Integer.toString( hours ) );
retval.append( ":" );
if( minutes < 10 )
{
retval.append( "0" );
}
retval.append( Integer.toString( minutes ) );
return retval.toString();
}
}