### Manage Calendar Collections via CLI

Source: https://context7.com/ical4j/ical4j-user-guide/llms.txt

Provides examples of using the 'ict' command-line tool to create, update, and filter calendar events and to-do items.

```bash
# Create a new collection
ict mkcol my-calendar

# Create a new event
ict new event my-calendar -summary "Team Meeting" -dtstart "2024-07-01T10:00:00" -dtend "2024-07-01T11:00:00"

# Create a to-do item
ict new todo my-todo-list -summary "Finish Report" -due "2024-07-05"

# List events with filter
ict ls my-calendar -filter "status=confirmed"

# Import/export calendar files
ict import -file="/path/to/calendar.ics" my-calendar
ict export -file="/path/to/exported.ics" my-calendar
```

--------------------------------

### Create a four-hour meeting event using Java

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/examples/model.md

Provides a Java example for creating a meeting event with a four-hour duration using the iCal4j library. It includes setting up time zones, start and end times, event details, attendees, and generating a unique identifier. Dependencies include `java.util.TimeZone`, `java.util.GregorianCalendar`, and iCal4j model classes.

```java
// 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.add(tz.getTimeZoneId());

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

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

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

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


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

--------------------------------

### Create Simple vCard with Properties (Java)

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/vcard/examples.md

Demonstrates the creation of a simple vCard object in Java. It involves initializing a list of properties, adding standard properties like Source, Name, and Kind, and also includes an example of adding a custom property. The final vCard is constructed from this list of properties.

```java
List<Property> props = new ArrayList<Property>();
props.add(new Source(URI.create("ldap://ldap.example.com/cn=Babs%20Jensen,%20o=Babsco,%20c=US")));
props.add(new Name("Babs Jensen's Contact Information"));
props.add(Kind.INDIVIDUAL);
// add a custom property..
props.add(new Property("test") {
    @Override
    public String getValue() {
        return null;
    }

    @Override
    public void validate() throws ValidationException {
    }
});

VCard vcard = new VCard(props);
```

--------------------------------

### Render Basic To-Do Items in Java

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/template/examples.md

Demonstrates how to initialize a ToDoModel and render it into plain text, Markdown, or HTML formats using the TemplateEngine.

```java
ToDoModel model = new ToDoModel(todo);
// no format
model.toString();

// markdown format
TemplateEngine engine = new TemplateEngineFactory().newInstance();
StringOutput output = new StringOutput();
engine.render("todo/markdown.jte", model, output);
output.toString();

// html format
output = new StringOutput();
engine.render("todo/html.jte", model, output);
output.toString();
```

--------------------------------

### Render Availability Models using TemplateEngine

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/template/examples.md

Demonstrates rendering an AvailabilityModel into plain text, Markdown, or HTML. This process utilizes the TemplateEngine to map availability data fields like start time, end time, and status into structured formats.

```java
AvailabilityModel model = new AvailabilityModel(availability);
// no format
model.toString();

// markdown format
TemplateEngine engine = new TemplateEngineFactory().newInstance();
StringOutput output = new StringOutput();
engine.render("availability/markdown.jte", model, output);
output.toString();

// html format
output = new StringOutput();
engine.render("availability/html.jte", model, output);
output.toString();
```

--------------------------------

### Update Collection Metadata with ict CLI

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/command/index.md

Shows how to update metadata for existing collections using the 'ict set' command. Examples include setting the name, color, description, and timezone of a collection.

```shell
> ict set my-calendar name "My remote calendar"
Updated collection 'my-calendar' with name 'My remote calendar'.

> ict set my-calendar color "#FF0000"
Updated collection 'my-calendar' with color '#FF0000'.

> ict set my-todo-list description "My personal to-do list"
Updated collection 'my-todo-list' with description 'My personal to-do list'.

> ict set my-calendar timezone "America/New_York"
Updated collection 'my-calendar' with timezone 'America/New_York'.
```

--------------------------------

### Render Recurring To-Do Items in Java

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/template/examples.md

Shows how to render To-Do items that include recurrence rules by providing a period start and end to the ToDoModel.

```java
ToDoModel model = new ToDoModel(recurringTodo, periodStart, periodEnd);
// no format
model.toString();

// markdown format
TemplateEngine engine = new TemplateEngineFactory().newInstance();
StringOutput output = new StringOutput();
engine.render("todo/markdown-occurrences.jte", model, output);
output.toString();
```

--------------------------------

### Sort Collection Objects

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/command/index.md

Explains how to order listed objects within a collection based on specific metadata properties like start date.

```shell
> ict ls my-calendar -sort "dtstart:asc"
```

--------------------------------

### Create Meeting Invite with iCal4j (Java)

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/template/groupware/meeting.md

This Java code snippet illustrates how to construct a meeting invitation using the iCal4j library. It takes VCard objects for participants and sets meeting properties like organizer, chair, start time, and duration. The output is a VEVENT object conforming to iCalendar standards.

```java
VCard organizer = ...;
VCard chair = ...;

VEvent meeting = new Meeting().organizer(organizer)
            .chair(new Contact(chair))
            .start(LocalDate.of(2023, 11, 13).atStartOfDay())
            .duration(Duration.ofMinutes(30)).apply();
```

--------------------------------

### Render Basic Journal Entries in Java

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/template/examples.md

Demonstrates how to render a simple journal entry with date, summary, and description using the JournalModel and JTE templates.

```java
JournalModel model = new JournalModel(journal);
// no format
model.toString();

// markdown format
TemplateEngine engine = new TemplateEngineFactory().newInstance();
StringOutput output = new StringOutput();
engine.render("journal/markdown.jte", model, output);
output.toString();

// html format
output = new StringOutput();
engine.render("journal/html.jte", model, output);
output.toString();
```

--------------------------------

### Create vCard Contacts

Source: https://context7.com/ical4j/ical4j-user-guide/llms.txt

Shows how to instantiate a VCard object and populate it with properties such as names, emails, and contact information.

```java
import net.fortuna.ical4j.vcard.VCard;
import net.fortuna.ical4j.vcard.Property;
import net.fortuna.ical4j.vcard.property.*;
import java.util.ArrayList;
import java.util.List;
import java.net.URI;

List<Property> props = new ArrayList<>();
props.add(new Source(URI.create("ldap://ldap.example.com/cn=John%20Doe,%20o=Example,%20c=US")));
props.add(new Name("John Doe's Contact Information"));
props.add(Kind.INDIVIDUAL);
props.add(new Fn("John Doe"));
props.add(new Email("john.doe@example.com"));
props.add(new Tel("+1-555-123-4567"));

VCard vcard = new VCard(props);
```

--------------------------------

### Create a new event

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/serializer/jotn/event.md

Creates a new event with the provided details. Supports properties like DTSTART, SUMMARY, and CATEGORIES.

```APIDOC
## POST /v1/events

### Description
Creates a new event with the provided details. Supports properties like DTSTART, SUMMARY, and CATEGORIES.

### Method
POST

### Endpoint
https://api.example.com/v1/events

### Parameters
#### Request Body
- **dtstart** (string) - Required - The start date/time of the event.
- **summary** (string) - Required - The summary or title of the event.
- **categories** (string) - Optional - Categories associated with the event.

### Request Example
```json
{
  "dtstart": "2024-01-01",
  "summary": "New Years Day",
  "categories": "holidays"
}
```

### Response
#### Success Response (200)
- **uid** (string) - The unique identifier for the event.
- **dtstamp** (string) - The timestamp when the event was created or last modified.
- **created** (string) - The creation timestamp of the event.
- **last-modified** (string) - The last modification timestamp of the event.
- **dtstart** (string) - The start date/time of the event.
- **summary** (string) - The summary or title of the event.
- **categories** (string) - Categories associated with the event.

#### Response Example
```json
{
  "uid": "1234-abcd",
  "dtstamp": "2024-01-17T10:59:00Z",
  "created": "2024-01-17T10:59:00Z",
  "last-modified": "2024-01-17T10:59:00Z",
  "dtstart": "2024-01-01",
  "summary": "New Years Day",
  "categories": "holidays"
}
```
```

--------------------------------

### Manage Timezones with TimeZoneRegistry

Source: https://context7.com/ical4j/ical4j-user-guide/llms.txt

Demonstrates how to retrieve timezone definitions, associate them with calendar events, and handle custom registry configurations for compatibility.

```java
import net.fortuna.ical4j.model.*;
import net.fortuna.ical4j.model.component.VTimeZone;
import net.fortuna.ical4j.model.component.VEvent;

// Get default timezone registry
TimeZoneRegistry registry = TimeZoneRegistryFactory.getInstance().createRegistry();
TimeZone timezone = registry.getTimeZone("Europe/Berlin");
VTimeZone tz = timezone.getVTimeZone();

// Create event with proper timezone
DateTime start = new DateTime(startDate, timezone);
DateTime end = new DateTime(endDate, timezone);
VEvent meeting = new VEvent(start, end, "Meeting with Timezone");

// Add VTimeZone to calendar
Calendar calendar = new Calendar();
calendar.add(tz);
calendar.add(meeting);

// Use Outlook-compatible timezone definitions
TimeZoneRegistry outlookRegistry = new TimeZoneRegistryImpl("zoneinfo-outlook/");
TimeZone outlookTz = outlookRegistry.getTimeZone("America/New_York");

// Get timezone from parsed calendar
CalendarBuilder builder = new CalendarBuilder();
Calendar parsedCal = builder.build(new FileInputStream("mycalendar.ics"));
TimeZoneRegistry parsedRegistry = builder.getRegistry();
TimeZone parsedTz = parsedRegistry.getTimeZone("Australia/Melbourne");
```

--------------------------------

### Parsing and rendering iCalendar data with Groovlets

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/groovy.md

An example of a Groovlet that fetches a calendar from a URL, parses it using CalendarBuilder, and renders event summaries into an HTML table.

```groovy
import net.fortuna.ical4j.data.CalendarBuilder
import net.fortuna.ical4j.model.Component

html.html {
    body {
        def builder = new CalendarBuilder()
        def calendar = builder.build(new URL(request.getParameter("u")).openStream())
        table {
            for (event in calendar.getComponents(Component.VEVENT)) {
                tr { td event.getSummary().getValue(); td event.getStartDate().getDate() }
            }
        }
    }
}
```

--------------------------------

### Render Contact Models using TemplateEngine

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/template/examples.md

Demonstrates rendering a ContactModel into plain text, Markdown, or HTML. It uses a TemplateEngineFactory to generate formatted output based on specific template files.

```java
ContactModel model = new ContactModel(contact);
// no format
model.toString();

// markdown format
TemplateEngine engine = new TemplateEngineFactory().newInstance();
StringOutput output = new StringOutput();
engine.render("contact/markdown.jte", model, output);
output.toString();

// html format
output = new StringOutput();
engine.render("contact/html.jte", model, output);
output.toString();
```

--------------------------------

### Accessing Event and To-Do Properties in Java

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/components.md

Demonstrates how to retrieve specific properties from iCalendar VEVENT and VTODO components using property accessors in Java. This includes getting start times for events and categories for to-dos.

```java
DtStart<LocalDate> start = event.getDateTimeStart();

List<Categories> categories = todo.getCategories();
```

--------------------------------

### Create Calendar and To-Do Objects with ict Strategies

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/command/index.md

Illustrates the use of predefined strategies ('event', 'todo') with the 'ict new' command to create calendar events and to-do items. It includes setting summary, start/end times, and due dates.

```shell
> ict new event my-calendar -summary "Team Meeting" -dtstart "2024-07-01T10:00:00" -dtend "2024-07-01T11:00:00"
Created event with UID '0987654321' in collection 'my-calendar'.

> ict new todo my-todo-list -summary "Finish Report" -due "2024-07-05"
Created to-do item with UID '1122334455' in collection 'my-todo-list'.
```

--------------------------------

### Modifying Event and To-Do Properties in Java

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/components.md

Illustrates how to safely modify properties of iCalendar VEVENT and VTODO components using property modifiers in Java. Examples show setting the start date/time for an event and adding categories to a to-do.

```java
event.with(DTSTART, new DtStart("20240101T0900000"));

todo.with(CATEGORIES, new Categories("travel"));
```

--------------------------------

### Apply Filters and Configure Default Settings

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/command/index.md

Shows how to filter collection objects by metadata, set default filters for recurring commands, and create named filter shortcuts.

```shell
> ict ls my-calendar -filter "status=confirmed"
> ict rm my-todo-list -filter "due<2024-07-01"
> ict configure set default-filter "status=confirmed"
> ict configure set filter "upcoming-events=status=confirmed;start>now"
```

--------------------------------

### Create Collections with ict CLI

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/command/index.md

Demonstrates how to create different types of collections (calendars, addressbooks, tasks, journals, notes) using the 'ict mkcol' command. It shows how to specify the collection type or use the default.

```shell
> ict mkcol -type=tasks my-todo-list
Collection 'my-todo-list' of type 'tasks' created.

> ict mkcol my-calendar
Collection 'my-calendar' of type 'calendars' created.
```

--------------------------------

### Configure Compatibility Hints via System Properties

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/compatibility.md

Illustrates how to pass compatibility hints as JVM arguments during application startup. This is useful for overriding default configurations without modifying source code or property files.

```bash
java -Dical4j.unfolding.relaxed=true <some_program>
```

--------------------------------

### Render Event with Alarms in Plain Text

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/template/examples.md

Provides an example of rendering an iCalendar event that includes alarms or reminders into plain text format using the ical4j library.

```java
EventModel model = new EventModel(eventWithAlarms);
// no format
model.toString();
// Output:
// Event: Doctor Appointment
// When: 2024-07-20T09:00 to 2024-07-20T10:00
// Description: Annual check-up with Dr. Smith.
// Alarms:
// - 30 minutes before
// - 1 day before

// markdown format
TemplateEngine engine = new TemplateEngineFactory().newInstance();
```

--------------------------------

### Working with Recurrence Rules (RRULE)

Source: https://context7.com/ical4j/ical4j-user-guide/llms.txt

Provides examples of building complex recurrence patterns using the Recur.Builder class. These rules can be added to VEvent components to define repeating schedules.

```java
import net.fortuna.ical4j.model.Recur;
import net.fortuna.ical4j.model.property.RRule;
import net.fortuna.ical4j.model.component.VEvent;

Recur recur = new Recur.Builder()
    .frequency(Recur.Frequency.MONTHLY)
    .interval(3)
    .dayList(new WeekDayList(WeekDay.SU))
    .build();
recur.setSetPosList(new NumberList("-1"));

RRule rrule = new RRule(recur);
event.add(rrule);

Recur yearlyRecur = new Recur.Builder()
    .frequency(Recur.Frequency.YEARLY)
    .monthList(new NumberList("4"))
    .dayList(new WeekDayList(WeekDay.SU))
    .build();
yearlyRecur.setSetPosList(new NumberList("3"));

Recur bimonthly = new Recur.Builder()
    .frequency(Recur.Frequency.MONTHLY)
    .interval(2)
    .monthDayList(new NumberList("29"))
    .build();
```

--------------------------------

### Import and Export iCalendar files via CLI

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/command/index.md

Demonstrates how to import calendar files into a collection and export entire collections or specific objects using their UID.

```shell
> ict import -file="/path/to/calendar.ics" my-calendar
> ict export -file="/path/to/exported_calendar.ics" my-calendar
> ict export -file="/path/to/exported_event.ics" my-calendar:0987654321
```

--------------------------------

### Render Recurring Event in Plain Text and Markdown

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/template/examples.md

Shows how to render recurring iCalendar events, including recurrence rules, into plain text and markdown formats. This example utilizes the ical4j library and a template engine.

```java
EventModel model = new EventModel(event, periodStart, periodEnd);

// no format
model.toString();

// Output:
// Event: Weekly Standup
// When: Recurs every week on Monday at 09:00 from 2024-07-01 to 2024-12-31
// Description: Weekly team standup meeting.

// markdown format
TemplateEngine engine = new TemplateEngineFactory().newInstance();
StringOutput output = new StringOutput();
engine.render("event/markdown-occurrences.jte", model, output);
output.toString();

// Output:
// # Event: Weekly Standup
// **When:** Monday 21 May, Monday 28 May, Monday 4 June, ...
// **Description:** Weekly team standup meeting.
```

--------------------------------

### Configure remote repositories and workspace synchronization

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/command/index.md

Commands to set remote repository URLs for calendars and addressbooks, clone existing repositories into new workspaces, and perform synchronization between local and remote storage.

```shell
> ict configure set remote.calendars "https://github.com/nodelogicau/calendars.git"
> ict configure set remote.addressbooks "https://github.com/nodelogicau/cards.git"
> ict clone https://github.com/nodelogicau/calendars.git work-project-b
> ict sync
```

--------------------------------

### Manage Workspaces

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/command/index.md

Provides commands to switch between different data workspaces and inspect the current active workspace configuration.

```shell
> ict chw work-project-a
> ict pws
```

--------------------------------

### Manage Calendar Events via HTTP API

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/serializer/jotn/event.md

Demonstrates standard RESTful operations including creating, updating, retrieving, and deleting calendar events using the JOT serialization format. These examples show the request payloads and expected JSON responses for various event lifecycle actions.

```json
POST https://api.example.com/v1/events
{
  "dtstart": "2024-01-01",
  "summary": "New Years Day",
  "categories": "holidays"
}
```

```json
POST https://api.example.com/v1/events/1234-abcd
{
  "rrule": "FREQ=YEARLY"
}
```

```json
POST https://api.example.com/v1/events/1234-abcd/20250101
{
  "description": "New Years Day (2025)"
}
```

```json
POST https://api.example.com/v1/events/1234-abcd
{
  "exdate": "20260101"
}
```

```json
GET https://api.example.com/v1/events/1234-abcd
```

```json
PATCH https://api.example.com/v1/events/1234-abcd
{
  "summary": "New Years Day (Public Holiday)"
}
```

```json
DELETE https://api.example.com/v1/events/1234-abcd
```

--------------------------------

### Set Object Properties with ict CLI

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/command/index.md

Demonstrates using the 'ict set' command to update properties of calendar and to-do objects, such as status and conference links. It also covers setting custom metadata properties.

```shell
> ict set status my-todo-list:1122334455 "in-progress"
Set status of 'my-todo-list:1122334455' to 'in-progress'.

> ict set conference my-calendar:0987654321 "https://meet.example.com/meeting123"
Set conference link to 'my-calendar:0987654321'.

> ict add x-property my-calendar:0987654321 "X-CUSTOM-PROP:Custom Value"
Added custom property 'X-CUSTOM-PROP' to 'my-calendar:0987654321'.

> ict set x-property my-calendar:0987654321 "X-CUSTOM-PROP:Updated Value"
Set custom property 'X-CUSTOM-PROP' on 'my-calendar:0987654321' to 'Updated Value'.
```

--------------------------------

### Add Subcomponents to Objects with ict CLI

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/command/index.md

Demonstrates how to add subcomponents like participants and notifications to existing calendar objects using the 'ict new' command. It shows targeting specific objects by collection and UID.

```shell
> ict new participant my-calendar:0987654321 @joeb@example.com -required
Added participant 'joeb' as required to 'my-calendar:0987654321'.

> ict new notify my-calendar:0987654321 "email:30m"
Added notification for 'my-calendar:0987654321' to email 30 minutes before start.
```

--------------------------------

### Example iCalendar Object Properties (JSON)

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/serializer/jotn/calendar.md

An example JSON structure representing an iCalendar object with various properties, including those that can appear once and those that can appear multiple times. This serves as a reference for the data format used.

```json
{
  "uid": "1234-abcd",
  "last-modified": "2024-01-17T10:59:00Z",
  "url": "https://example.com/public_holidays",
  "refresh-interval": "P1W",
  "source": "https://example.com/public_holidays.ics",
  "color": "orange",
  "name": "International Public Holidays",
  "description": "Globally recognised public holidays",
  "categories": ["holidays", "global"],
  "image": "https://example.com/images/holiday.png"
}
```

--------------------------------

### Example xCal XML Output

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/serializer/index.md

This is an example of the XML output generated when serializing an iCalendar file to xCal format. It represents the calendar data, including VCALENDAR properties and components like VEVENT and VTIMEZONE, in a structured XML format.

```xml
<icalendar xmlns="urn:ietf:params:xml:ns:icalendar-2.0">
  <vcalendar>
    <properties>
      <calscale>
        <parameters/>
        <text>GREGORIAN</text>
      </calscale>
      <method>
        <parameters/>
        <text>PUBLISH</text>
      </method>
      <prodid>
        <parameters/>
        <text>-//Apple Computer, Inc//iCal 1.0//EN</text>
      </prodid>
      <x-wr-calname>
        <parameters>
          <value>text</value>
        </parameters>
        <text>Australian Holidays</text>
      </x-wr-calname>
      <x-wr-relcalid>
        <parameters>
          <value>text</value>
        </parameters>
        <text>D4167B74-C414-11D6-BA97-003065F198AC</text>
      </x-wr-relcalid>
      <x-wr-timezone>
        <parameters>
          <value>text</value>
        </parameters>
        <text>Asia/Hong_Kong</text>
      </x-wr-timezone>
      <version>
        <parameters/>
        <text>2.0</text>
      </version>
    </properties>
    <components>
      <vtimezone>
        <properties>
          <tzid>
            <parameters/>
            <text>Asia/Hong_Kong</text>
          </tzid>
          <last-modified>
            <parameters/>
            <date-time>2006-01-17T16:36:57Z</date-time>
          </last-modified>
        </properties>
        <components>
          <standard>
            <properties>
              <dtstart>
                <parameters/>
                <date-time>1932-12-13T20:45:52</date-time>
              </dtstart>
              <tzoffsetto>
                <parameters/>
                <utc-offset>+08:00</utc-offset>
              </tzoffsetto>
              <tzoffsetfrom>
                <parameters/>
                <utc-offset>Z</utc-offset>
              </tzoffsetfrom>
              <tzname>
                <parameters/>
                <text>HKT</text>
              </tzname>
            </properties>
            <components/>
          </standard>
          <daylight>
            <properties>
              <dtstart>
                <parameters/>
                <date-time>1946-04-20T03:30:00</date-time>
              </dtstart>
              <tzoffsetto>
                <parameters/>
                <utc-offset>+09:00</utc-offset>
              </tzoffsetto>
              <tzoffsetfrom>
                <parameters/>
                <utc-offset>+08:00</utc-offset>
              </tzoffsetfrom>
              <tzname>
                <parameters/>
                <text>HKST</text>
              </tzname>
            </properties>
            <components/>
          </daylight>
        </components>
      </vtimezone>
      <vevent>
        <properties>
          <uid>
            <parameters/>
            <text>D416469E-C414-11D6-BA97-003065F198AC</text>
          </uid>
          <dtstamp>
            <parameters/>
            <date-time>2002-09-06T09:44:59Z</date-time>
          </dtstamp>
          <summary>
            <parameters/>
            <text>Australia Day</text>
          </summary>
          <rrule>
            <parameters/>
            <recur>FREQ=YEARLY;INTERVAL=1;BYMONTH=1</recur>
          </rrule>
          <dtstart>
            <parameters>
              <value>date</value>
            </parameters>
            <date>2002-01-26</date>
          </dtstart>
          <dtend>
            <parameters>
              <value>date</value>
            </parameters>
            <date>2002-01-27</date>
          </dtend>
        </properties>
        <components/>
      </vevent>
    </components>
  </vcalendar>
</icalendar>
```

--------------------------------

### Configure UID Generation Strategy with ict CLI

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/command/index.md

Shows how to change the UID generation strategy from the default UUID to 'sequential' using the 'ict configure set' command. This affects how unique identifiers are created for new objects.

```shell
> ict configure set uid-strategy "sequential"
Set UID generation strategy to 'sequential'.
> ict new event my-calendar -summary "Project Kickoff" -dtstart "2024-07-02T09:00:00" -dtend "2024-07-02T10:00:00"
Created event with UID '0987654322' in collection 'my-calendar'.
```

--------------------------------

### Configure user settings and preferences

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/command/index.md

Commands to update global tool settings such as user identity for revision tracking. These settings persist across sessions and influence how objects are managed.

```shell
> ict configure set username "John Doe"
> ict configure set email "jdoe@example.com"
```

--------------------------------

### Delete an existing event

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/serializer/jotn/event.md

Deletes an existing event from the system.

```APIDOC
## DELETE /v1/events/{eventId}

### Description
Deletes an existing event from the system.

### Method
DELETE

### Endpoint
https://api.example.com/v1/events/{eventId}

### Parameters
#### Path Parameters
- **eventId** (string) - Required - The unique identifier of the event to delete.

### Response
#### Success Response (200)
- Returns the deleted event object or a confirmation message.
- The structure is similar to the response of retrieving an event.

#### Response Example
```json
[
    {
        "uid": "1234-abcd",
        "dtstamp": "2024-01-17T10:59:00Z",
        "created": "2024-01-17T10:59:00Z",
        "last-modified": "2024-01-17T10:59:00Z",
        "dtstart": "2024-01-01",
        "summary": "New Years Day (Public Holiday)",
        "categories": "holidays",
        "rrule": "FREQ=YEARLY",
        "exdate": "20260101"
    },
    {
        "uid": "1234-abcd",
        "recurrence-id": "20250101",
        "dtstamp": "2024-01-17T10:59:00Z",
        "created": "2024-01-17T10:59:00Z",
        "last-modified": "2024-01-17T10:59:00Z",
        "dtstart": "2024-01-01",
        "summary": "New Years Day",
        "categories": "holidays",
        "description": "New Years Day (2025)"
    }
]
```
```

--------------------------------

### Enable Compatibility Hints Programmatically

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/compatibility.md

Demonstrates how to enable specific compatibility features at runtime using the CompatibilityHints utility class. This method requires the key constant and a boolean value to toggle the hint.

```java
CompatibilityHints.setHintEnabled(KEY_RELAXED_UNFOLDING, true);
```

--------------------------------

### Create an all-day event using the fluent API in Java

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/examples/model.md

Demonstrates creating an all-day iCalendar event using the fluent API of the iCal4j library in Java. This method allows for a more streamlined construction of the VEvent object and its properties.

```java
net.fortuna.ical4j.model.Calendar cal = new net.fortuna.ical4j.model.Calendar()
    .withComponent(
        new VEvent(new Date(calendar.getTime()), "Christmas Day")
            .withProperty(ug.generateUid()).getFluentTarget()).getFluentTarget();
```

--------------------------------

### Customize an occurrence of a recurring event

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/serializer/jotn/event.md

Customizes a specific occurrence of a recurring event by providing a DESCRIPTION.

```APIDOC
## POST /v1/events/{eventId}/{occurrenceId}

### Description
Customizes a specific occurrence of a recurring event by providing a DESCRIPTION.

### Method
POST

### Endpoint
https://api.example.com/v1/events/{eventId}/{occurrenceId}

### Parameters
#### Path Parameters
- **eventId** (string) - Required - The unique identifier of the recurring event.
- **occurrenceId** (string) - Required - The identifier for the specific occurrence (e.g., YYYYMMDD).

#### Request Body
- **description** (string) - Optional - A custom description for this specific occurrence.

### Request Example
```json
{
  "description": "New Years Day (2025)"
}
```

### Response
#### Success Response (200)
- **uid** (string) - The unique identifier for the event.
- **recurrence-id** (string) - The identifier for the customized occurrence.
- **dtstamp** (string) - The timestamp when the event was created or last modified.
- **created** (string) - The creation timestamp of the event.
- **last-modified** (string) - The last modification timestamp of the event.
- **dtstart** (string) - The start date/time of the event.
- **summary** (string) - The summary or title of the event.
- **categories** (string) - Categories associated with the event.
- **description** (string) - The custom description for this occurrence.

#### Response Example
```json
{
    "uid": "1234-abcd",
    "recurrence-id": "20250101",
    "dtstamp": "2024-01-17T10:59:00Z",
    "created": "2024-01-17T10:59:00Z",
    "last-modified": "2024-01-17T10:59:00Z",
    "dtstart": "2024-01-01",
    "summary": "New Years Day",
    "categories": "holidays",
    "description": "New Years Day (2025)"
}
```
```

--------------------------------

### Update an existing event (idempotently)

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/serializer/jotn/event.md

Updates an existing event using a PATCH request. Changes are idempotent.

```APIDOC
## PATCH /v1/events/{eventId}

### Description
Updates an existing event using a PATCH request. Changes are idempotent.

### Method
PATCH

### Endpoint
https://api.example.com/v1/events/{eventId}

### Parameters
#### Path Parameters
- **eventId** (string) - Required - The unique identifier of the event to update.

#### Request Body
- **summary** (string) - Optional - The updated summary or title of the event.
- Other updatable VEVENT properties can be included here.

### Request Example
```json
{
  "summary": "New Years Day (Public Holiday)"
}
```

### Response
#### Success Response (200)
- **uid** (string) - The unique identifier for the event.
- **dtstamp** (string) - The timestamp when the event was created or last modified.
- **created** (string) - The creation timestamp of the event.
- **last-modified** (string) - The last modification timestamp of the event.
- **dtstart** (string) - The start date/time of the event.
- **summary** (string) - The updated summary or title of the event.
- **categories** (string) - Categories associated with the event.
- **rrule** (string) - The recurrence rule applied to the event.
- **exdate** (string) - The date/time of a cancelled occurrence.

#### Response Example
```json
{
    "uid": "1234-abcd",
    "dtstamp": "2024-01-17T10:59:00Z",
    "created": "2024-01-17T10:59:00Z",
    "last-modified": "2024-01-17T10:59:00Z",
    "dtstart": "2024-01-01",
    "summary": "New Years Day (Public Holiday)",
    "categories": "holidays",
    "rrule": "FREQ=YEARLY",
    "exdate": "20260101"
}
```
```

--------------------------------

### Create a new iCalendar object using the fluent API in Java

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/examples/model.md

Illustrates how to create an iCalendar object more succinctly using the fluent API provided by the iCal4j library in Java. This approach chains method calls for a more readable and concise code structure.

```java
Calendar calendar = new Calendar().withProdId("-//Ben Fortuna//iCal4j 1.0//EN")
    .withDefaults().getFluentTarget();

// Add events, etc..
calendar = calendar.withComponent(...).getFluentTarget();
```

--------------------------------

### Add Metadata to Calendar Objects with ict CLI

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/command/index.md

Explains how to add various metadata like attachments, comments, and categories to calendar objects using the 'ict add' command. It shows how to specify the object and the metadata to be added.

```shell
> ict add attach my-calendar:0987654321 "/path/to/agenda.pdf"
Added attachment to 'my-calendar:0987654321'.

> ict add comment my-calendar:0987654321 "Discuss project updates"
Added comment to 'my-calendar:0987654321'.

> ict add categories my-calendar:0987654321 "Work" "Important"
Added categories to 'my-calendar:0987654321'.
```

--------------------------------

### Retrieve all occurrences of a recurring event

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/serializer/jotn/event.md

Retrieves all occurrences, including customized and cancelled ones, of a recurring event.

```APIDOC
## GET /v1/events/{eventId}

### Description
Retrieves all occurrences, including customized and cancelled ones, of a recurring event.

### Method
GET

### Endpoint
https://api.example.com/v1/events/{eventId}

### Parameters
#### Path Parameters
- **eventId** (string) - Required - The unique identifier of the recurring event.

### Response
#### Success Response (200)
- An array of event occurrence objects, each potentially including:
  - **uid** (string) - The unique identifier for the event.
  - **recurrence-id** (string) - The identifier for a customized occurrence.
  - **dtstamp** (string) - The timestamp when the event was created or last modified.
  - **created** (string) - The creation timestamp of the event.
  - **last-modified** (string) - The last modification timestamp of the event.
  - **dtstart** (string) - The start date/time of the event.
  - **summary** (string) - The summary or title of the event.
  - **categories** (string) - Categories associated with the event.
  - **rrule** (string) - The recurrence rule applied to the event.
  - **exdate** (string) - The date/time of a cancelled occurrence.
  - **description** (string) - The custom description for a specific occurrence.

#### Response Example
```json
[
    {
        "uid": "1234-abcd",
        "dtstamp": "2024-01-17T10:59:00Z",
        "created": "2024-01-17T10:59:00Z",
        "last-modified": "2024-01-17T10:59:00Z",
        "dtstart": "2024-01-01",
        "summary": "New Years Day",
        "categories": "holidays",
        "rrule": "FREQ=YEARLY",
        "exdate": "20260101"
    },
    {
        "uid": "1234-abcd",
        "recurrence-id": "20250101",
        "dtstamp": "2024-01-17T10:59:00Z",
        "created": "2024-01-17T10:59:00Z",
        "last-modified": "2024-01-17T10:59:00Z",
        "dtstart": "2024-01-01",
        "summary": "New Years Day",
        "categories": "holidays",
        "description": "New Years Day (2025)"
    }
]
```
```

--------------------------------

### Cancel an occurrence of a recurring event

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/serializer/jotn/event.md

Cancels a specific occurrence of a recurring event by adding it to the EXDATE list.

```APIDOC
## POST /v1/events/{eventId}

### Description
Cancels a specific occurrence of a recurring event by adding it to the EXDATE list.

### Method
POST

### Endpoint
https://api.example.com/v1/events/{eventId}

### Parameters
#### Path Parameters
- **eventId** (string) - Required - The unique identifier of the recurring event.

#### Request Body
- **exdate** (string) - Required - The date/time of the occurrence to cancel (e.g., "20260101").

### Request Example
```json
{
  "exdate": "20260101"
}
```

### Response
#### Success Response (200)
- **uid** (string) - The unique identifier for the event.
- **dtstamp** (string) - The timestamp when the event was created or last modified.
- **created** (string) - The creation timestamp of the event.
- **last-modified** (string) - The last modification timestamp of the event.
- **dtstart** (string) - The start date/time of the event.
- **summary** (string) - The summary or title of the event.
- **categories** (string) - Categories associated with the event.
- **rrule** (string) - The recurrence rule applied to the event.
- **exdate** (string) - The date/time of the cancelled occurrence.

#### Response Example
```json
{
    "uid": "1234-abcd",
    "dtstamp": "2024-01-17T10:59:00Z",
    "created": "2024-01-17T10:59:00Z",
    "last-modified": "2024-01-17T10:59:00Z",
    "dtstart": "2024-01-01",
    "summary": "New Years Day",
    "categories": "holidays",
    "rrule": "FREQ=YEARLY",
    "exdate": "20260101"
}
```
```

--------------------------------

### Add a recurrence rule to an event

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/serializer/jotn/event.md

Adds a recurrence rule (RRULE) to an existing event, allowing it to repeat.

```APIDOC
## POST /v1/events/{eventId}

### Description
Adds a recurrence rule (RRULE) to an existing event, allowing it to repeat.

### Method
POST

### Endpoint
https://api.example.com/v1/events/{eventId}

### Parameters
#### Path Parameters
- **eventId** (string) - Required - The unique identifier of the event to update.

#### Request Body
- **rrule** (string) - Required - The recurrence rule string (e.g., "FREQ=YEARLY").

### Request Example
```json
{
  "rrule": "FREQ=YEARLY"
}
```

### Response
#### Success Response (200)
- **uid** (string) - The unique identifier for the event.
- **dtstamp** (string) - The timestamp when the event was created or last modified.
- **created** (string) - The creation timestamp of the event.
- **last-modified** (string) - The last modification timestamp of the event.
- **dtstart** (string) - The start date/time of the event.
- **summary** (string) - The summary or title of the event.
- **categories** (string) - Categories associated with the event.
- **rrule** (string) - The recurrence rule applied to the event.

#### Response Example
```json
{
  "uid": "1234-abcd",
  "dtstamp": "2024-01-17T10:59:00Z",
  "created": "2024-01-17T10:59:00Z",
  "last-modified": "2024-01-17T10:59:00Z",
  "dtstart": "2024-01-01",
  "summary": "New Years Day",
  "categories": "holidays",
  "rrule": "FREQ=YEARLY"
}
```
```

--------------------------------

### Configure Compatibility Hints via Properties File

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/compatibility.md

Shows how to define compatibility settings in an ical4j.properties file located in the classpath. This allows for persistent configuration across application restarts.

```properties
ical4j.unfolding.relaxed=true

ical4j.unfolding.relaxed={true|false}
ical4j.parsing.relaxed={true|false}
ical4j.validation.relaxed={true|false}
ical4j.compatibility.outlook={true|false}
ical4j.compatibility.notes={true|false}
```

--------------------------------

### Create an all-day event using Java

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/examples/model.md

Shows how to create an all-day event in iCalendar format using Java and the iCal4j library. It involves setting a specific date and initializing a VEvent object, then generating a unique identifier for it. Dependencies include `java.util.Calendar` and iCal4j model classes.

```java
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.add(ug.generateUid());

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

--------------------------------

### Constructing vCard objects with ContentBuilder

Source: https://github.com/ical4j/ical4j-user-guide/blob/master/docs/groovy.md

Demonstrates how to use the ContentBuilder to define vCard properties, handle parameters, and encode binary data like photos. The builder simplifies the hierarchical structure of vCard objects compared to standard Java implementations.

```groovy
def builder = new ContentBuilder()
def card = builder.vcard() {
    version '4.0'
    fn 'test'
    n 'example' {
        value 'text'
    }
    photo(new File('http://example.com/photo.png').bytes.encodeBase64() as String)
}
card.validate()
```