Examples

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This page provides examples that demonstrate how to use iCal4j effectively.

Contents

Parsing a calendar file

FileInputStream fin = new FileInputStream("mycalendar.ics");

CalendarBuilder builder = new CalendarBuilder();

Calendar calendar = builder.build(fin);

Parsing a calendar string

String myCalendarString = ...

StringReader sin = new StringReader(myCalendarString);

CalendarBuilder builder = new CalendarBuilder();

Calendar calendar = builder.build(sin);

Creating a new calendar

Calendar calendar = new Calendar();
calendar.getProperties().add(new ProdId("-//Ben Fortuna//iCal4j 1.0//EN"));
calendar.getProperties().add(Version.VERSION_2_0);
calendar.getProperties().add(CalScale.GREGORIAN);

// Add events, etc..

Output:

BEGIN:VCALENDAR
PRODID:-//Ben Fortuna//iCal4j 1.0//EN
VERSION:2.0
CALSCALE:GREGORIAN
END:VCALENDAR

Creating an all day event

java.util.Calendar calendar = java.util.Calendar.getInstance();
calendar.set(java.util.Calendar.MONTH, java.util.Calendar.DECEMBER);
calendar.set(java.util.Calendar.DAY_OF_MONTH, 25);

// initialise as an all-day event..
VEvent christmas = new VEvent(new Date(calendar.getTime()), "Christmas Day");

// Generate a UID for the event..
UidGenerator ug = new UidGenerator("1");
christmas.getProperties().add(ug.generateUid());

net.fortuna.ical4j.model.Calendar cal = new net.fortuna.ical4j.model.Calendar();
cal.getComponents().add(christmas);

Output:

BEGIN:VEVENT
DTSTAMP:20050222T044240Z
DTSTART;VALUE=DATE:20051225
SUMMARY:Christmas Day
UID:20050222T044240Z-1@example.com
END:VEVENT

Creating a meeting of four hour duration

// Create a TimeZone
TimeZoneRegistry registry = TimeZoneRegistryFactory.getInstance().createRegistry();
TimeZone timezone = registry.getTimeZone("America/Mexico_City");
VTimeZone tz = timezone.getVTimeZone();

 // Start Date is on: April 1, 2008, 9:00 am
java.util.Calendar startDate = new GregorianCalendar();
startDate.setTimeZone(timezone);
startDate.set(java.util.Calendar.MONTH, java.util.Calendar.APRIL);
startDate.set(java.util.Calendar.DAY_OF_MONTH, 1);
startDate.set(java.util.Calendar.YEAR, 2008);
startDate.set(java.util.Calendar.HOUR_OF_DAY, 9);
startDate.set(java.util.Calendar.MINUTE, 0);
startDate.set(java.util.Calendar.SECOND, 0);

 // End Date is on: April 1, 2008, 13:00
java.util.Calendar endDate = new GregorianCalendar();
endDate.setTimeZone(timezone);
endDate.set(java.util.Calendar.MONTH, java.util.Calendar.APRIL);
endDate.set(java.util.Calendar.DAY_OF_MONTH, 1);
endDate.set(java.util.Calendar.YEAR, 2008);
endDate.set(java.util.Calendar.HOUR_OF_DAY, 13);
endDate.set(java.util.Calendar.MINUTE, 0);	
endDate.set(java.util.Calendar.SECOND, 0);

// Create the event
String eventName = "Progress Meeting";
DateTime start = new DateTime(startDate.getTime());
DateTime end = new DateTime(endDate.getTime());
VEvent meeting = new VEvent(start, end, eventName);

// add timezone info..
meeting.getProperties().add(tz.getTimeZoneId());

// generate unique identifier..
UidGenerator ug = new UidGenerator("uidGen");
Uid uid = ug.generateUid();
meeting.getProperties().add(uid);

// add attendees..
Attendee dev1 = new Attendee(URI.create("mailto:dev1@mycompany.com"));
dev1.getParameters().add(Role.REQ_PARTICIPANT);
dev1.getParameters().add(new Cn("Developer 1"));
meeting.getProperties().add(dev1);

Attendee dev2 = new Attendee(URI.create("mailto:dev2@mycompany.com"));
dev2.getParameters().add(Role.OPT_PARTICIPANT);
dev2.getParameters().add(new Cn("Developer 2"));
meeting.getProperties().add(dev2);

// Create a calendar
net.fortuna.ical4j.model.Calendar icsCalendar = new net.fortuna.ical4j.model.Calendar();
icsCalendar.getProperties().add(new ProdId("-//Events Calendar//iCal4j 1.0//EN"));
icsCalendar.getProperties().add(CalScale.GREGORIAN);


// Add the event and print
icsCalendar.getComponents().add(meeting);
System.out.println(icsCalendar);

Generating a calendar file

FileOutputStream fout = new FileOutputStream("mycalendar.ics");

CalendarOutputter outputter = new CalendarOutputter();
outputter.output(calendar, fout);

Attaching binary data

FileInputStream fin = new FileInputStream("etc/artwork/logo.png");
ByteArrayOutputStream bout = new ByteArrayOutputStream();
for (int i = fin.read(); i >= 0;) {
    bout.write(i);
    i = fin.read();
}

ParameterList params = new ParameterList();
params.add(Value.BINARY);
params.add(Encoding.BASE64);

Attach attach = new Attach(params, bout.toByteArray());

Output:

ATTACH;ENCODING=BASE64;VALUE=BINARY:iVBORw0KGgoAAAANSUhEUgAAAUYAAACJCAYAA
 ABQHpElAAAABHNCSVQICAgIfAhkiAAAABl0RVh0U29mdHdhcmUAd3d3Lmlua3NjYXBlLm9yZ
 5vuPBoAABPKSURBVHic7d15tFX1dcDx72aQyQkMqAiIojjFASc0GmOlRqKmcR6XpkaJYtrU1
 LYSp0ZZqxo1SZ2CUZPGqlXRGEdAqzKoqGjqCKgoVFF8DkVEBJRh9499HiGXB /ec3/nnN89d
 3/WOmvx9J599r3vvf3O8Pvtn6gqzrkaiGwPzCw6jTZsjmrLqq9ERgGXFZdOmyajeuCqr0QOB
 ...


Filtering events

The correct way to filter events according to the spec (RFC2445) would be to construct a VFREEBUSY request that represents the properties of events that you are interested in. You would then pass this request as an argument to the constructor of a new VFREEBUSY, along with the list of components (events) you want to inspect to derive a VFREEBUSY instance that represents the consumed/free time based on the specified events (see the API Documentation for more information).

An easier way to achieve similar results is to use iCal4j filters to filter components with the specified properties. For example, to filter a list of events only occurring today you might do the following: 

java.util.Calendar today = java.util.Calendar.getInstance();
today.set(java.util.Calendar.HOUR_OF_DAY, 0);
today.clear(java.util.Calendar.MINUTE);
today.clear(java.util.Calendar.SECOND);

// create a period starting now with a duration of one (1) day..
Period period = new Period(new DateTime(today.getTime()), new Dur(1, 0, 0, 0));
Filter filter = new Filter(new PeriodRule(period));

List eventsToday = filter.filter(calendar.getComponents(Component.VEVENT));


Generating event dates

// Reading the file and creating the calendar
CalendarBuilder builder = new CalendarBuilder();
Calendar cal = null;
try {
	cal = builder.build(new FileInputStream("my.ics"));
} catch (IOException e) {
	e.printStackTrace();
} catch (ParserException e) {
	e.printStackTrace();
}


// Create the date range which is desired.
DateTime from = new DateTime("20100101T070000Z");
DateTime to = new DateTime("20100201T070000Z");;
Period period = new Period(from, to);


// For each VEVENT in the ICS
for (Object o : cal.getComponents("VEVENT")) {
	Component c = (Component)o;
	PeriodList list = c.calculateRecurrenceSet(period);

	for (Object po : list) {
		System.out.println((Period)po);
	}
}
Retrieved from "http://wiki.modularity.net.au/ical4j/index.php?title=Examples"
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