/**
* Copyright (c) 2012, Ben Fortuna
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* o Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* o 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.
*
* o Neither the name of Ben Fortuna nor the names of any other contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* 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.
*/
package net.fortuna.ical4j.util;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.URL;
import java.nio.charset.Charset;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import net.fortuna.ical4j.data.CalendarBuilder;
import net.fortuna.ical4j.data.ParserException;
import net.fortuna.ical4j.model.Calendar;
import net.fortuna.ical4j.model.Component;
import net.fortuna.ical4j.model.ComponentList;
import net.fortuna.ical4j.model.ConstraintViolationException;
import net.fortuna.ical4j.model.IndexedComponentList;
import net.fortuna.ical4j.model.Parameter;
import net.fortuna.ical4j.model.Property;
import net.fortuna.ical4j.model.component.VTimeZone;
import net.fortuna.ical4j.model.parameter.TzId;
import net.fortuna.ical4j.model.property.Method;
import net.fortuna.ical4j.model.property.Uid;
/**
* $Id$
*
* Created on 10/11/2006
*
* Utility method for working with {@link Calendar}s.
* @author Ben Fortuna
*/
public final class Calendars {
/**
* Constructor made private to enforce static nature.
*/
private Calendars() {
}
/**
* Loads a calendar from the specified file.
* @param filename the name of the file from which to load calendar data
* @return returns a new calendar instance initialised from the specified file
* @throws IOException occurs when there is an error reading the specified file
* @throws ParserException occurs when the data in the specified file is invalid
*/
public static Calendar load(final String filename) throws IOException, ParserException {
final FileInputStream fin = new FileInputStream(filename);
final CalendarBuilder builder = new CalendarBuilder();
return builder.build(fin);
}
/**
* Loads a calendar from the specified URL.
* @param url the URL from which to load calendar data
* @return returns a new calendar instance initialised from the specified URL
* @throws IOException occurs when there is an error reading from the specified URL
* @throws ParserException occurs when the data in the specified URL is invalid
*/
public static Calendar load(final URL url) throws IOException, ParserException {
final CalendarBuilder builder = new CalendarBuilder();
return builder.build(url.openStream());
}
/**
* Merge all properties and components from two specified calendars into one instance.
* Note that the merge process is not very sophisticated, and may result in invalid calendar
* data (e.g. multiple properties of a type that should only be specified once).
* @param c1 the first calendar to merge
* @param c2 the second calendar to merge
* @return a Calendar instance containing all properties and components from both of the specified calendars
*/
public static Calendar merge(final Calendar c1, final Calendar c2) {
final Calendar result = new Calendar();
result.getProperties().addAll(c1.getProperties());
for (final Iterator i = c2.getProperties().iterator(); i.hasNext();) {
final Property p = (Property) i.next();
if (!result.getProperties().contains(p)) {
result.getProperties().add(p);
}
}
result.getComponents().addAll(c1.getComponents());
for (final Iterator i = c2.getComponents().iterator(); i.hasNext();) {
final Component c = (Component) i.next();
if (!result.getComponents().contains(c)) {
result.getComponents().add(c);
}
}
return result;
}
/**
* Wraps a component in a calendar.
* @param component the component to wrap with a calendar
* @return a calendar containing the specified component
*/
public static Calendar wrap(final Component component) {
final ComponentList components = new ComponentList();
components.add(component);
return new Calendar(components);
}
/**
* Splits a calendar object into distinct calendar objects for unique
* identifers (UID).
* @param calendar a calendar instance
* @return an array of calendar objects
*/
public static Calendar[] split(final Calendar calendar) {
// if calendar contains one component or less, or is composed entirely of timezone
// definitions, return the original calendar unmodified..
if (calendar.getComponents().size() <= 1
|| calendar.getComponents(Component.VTIMEZONE).size() == calendar.getComponents().size()) {
return new Calendar[] {calendar};
}
final IndexedComponentList timezones = new IndexedComponentList(calendar.getComponents(Component.VTIMEZONE),
Property.TZID);
final Map calendars = new HashMap();
for (final Iterator i = calendar.getComponents().iterator(); i.hasNext();) {
final Component c = (Component) i.next();
if (c instanceof VTimeZone) {
continue;
}
final Uid uid = (Uid) c.getProperty(Property.UID);
Calendar uidCal = (Calendar) calendars.get(uid);
if (uidCal == null) {
uidCal = new Calendar(calendar.getProperties(), new ComponentList());
// remove METHOD property for split calendars..
for (final Iterator mp = uidCal.getProperties(Property.METHOD).iterator(); mp.hasNext();) {
uidCal.getProperties().remove(mp.next());
}
calendars.put(uid, uidCal);
}
for (final Iterator j = c.getProperties().iterator(); j.hasNext();) {
final Property p = (Property) j.next();
final TzId tzid = (TzId) p.getParameter(Parameter.TZID);
if (tzid != null) {
final VTimeZone timezone = (VTimeZone) timezones.getComponent(tzid.getValue());
if (!uidCal.getComponents().contains(timezone)) {
uidCal.getComponents().add(timezone);
}
}
}
uidCal.getComponents().add(c);
}
return (Calendar[]) calendars.values().toArray(new Calendar[calendars.values().size()]);
}
/**
* Returns a unique identifier as specified by components in the provided calendar.
* @param calendar a calendar instance
* @return the UID property
* @throws ConstraintViolationException if zero or more than one unique identifer is found in the specified calendar
*/
public static Uid getUid(final Calendar calendar) throws ConstraintViolationException {
Uid uid = null;
for (final Iterator i = calendar.getComponents().iterator(); i.hasNext();) {
final Component c = (Component) i.next();
for (final Iterator j = c.getProperties(Property.UID).iterator(); j.hasNext();) {
final Uid foundUid = (Uid) j.next();
if (uid != null && !uid.equals(foundUid)) {
throw new ConstraintViolationException("More than one UID found in calendar");
}
uid = foundUid;
}
}
if (uid == null) {
throw new ConstraintViolationException("Calendar must specify a single unique identifier (UID)");
}
return uid;
}
/**
* Returns an appropriate MIME Content-Type for the specified calendar object.
* @param calendar a calendar instance
* @param charset an optional encoding
* @return a content type string
*/
public static String getContentType(Calendar calendar, Charset charset) {
final StringBuffer b = new StringBuffer("text/calendar");
final Method method = (Method) calendar.getProperty(Property.METHOD);
if (method != null) {
b.append("; method=");
b.append(method.getValue());
}
if (charset != null) {
b.append("; charset=");
b.append(charset);
}
return b.toString();
}
}