Caldavsync Sources / file revision

 /**

  * 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();

     }

 }