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.model;

 import java.io.IOException;

 import java.net.URL;

 import java.util.Map;

 import java.util.Properties;

 import java.util.regex.Matcher;

 import java.util.regex.Pattern;

 import net.fortuna.ical4j.data.CalendarBuilder;

 import net.fortuna.ical4j.data.ParserException;

 import net.fortuna.ical4j.model.component.VTimeZone;

 import net.fortuna.ical4j.model.property.TzUrl;

 import net.fortuna.ical4j.util.CompatibilityHints;

 import net.fortuna.ical4j.util.Configurator;

 import net.fortuna.ical4j.util.ResourceLoader;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 import edu.emory.mathcs.backport.java.util.concurrent.ConcurrentHashMap;

 /**

  * $Id$

  *

  * Created on 18/09/2005

  *

  * The default implementation of a <code>TimeZoneRegistry</code>. This implementation will search the classpath for

  * applicable VTimeZone definitions used to back the provided TimeZone instances.

  * @author Ben Fortuna

  */

 public class TimeZoneRegistryImpl implements TimeZoneRegistry {

     private static final String DEFAULT_RESOURCE_PREFIX = "zoneinfo/";

     private static final Pattern TZ_ID_SUFFIX = Pattern.compile("(?<=/)[^/]*/[^/]*$");

     private static final String UPDATE_ENABLED = "net.fortuna.ical4j.timezone.update.enabled";

     private static final Map DEFAULT_TIMEZONES = new ConcurrentHashMap();

     private static final Properties ALIASES = new Properties();

     static {

         try {

             ALIASES.load(ResourceLoader.getResourceAsStream("net/fortuna/ical4j/model/tz.alias"));

         }

         catch (IOException ioe) {

             LogFactory.getLog(TimeZoneRegistryImpl.class).warn(

                     "Error loading timezone aliases: " + ioe.getMessage());

         }

         try {

         	ALIASES.load(ResourceLoader.getResourceAsStream("tz.alias"));

         }

         catch (Exception e) {

         	LogFactory.getLog(TimeZoneRegistryImpl.class).debug(

         			"Error loading custom timezone aliases: " + e.getMessage());

         }

     }

     private Map timezones;

     private String resourcePrefix;

     /**

      * Default constructor.

      */

     public TimeZoneRegistryImpl() {

         this(DEFAULT_RESOURCE_PREFIX);

     }

     /**

      * Creates a new instance using the specified resource prefix.

      * @param resourcePrefix a prefix prepended to classpath resource lookups for default timezones

      */

     public TimeZoneRegistryImpl(final String resourcePrefix) {

         this.resourcePrefix = resourcePrefix;

         timezones = new ConcurrentHashMap();

     }

     /**

      * {@inheritDoc}

      */

     public final void register(final TimeZone timezone) {

     	// for now we only apply updates to included definitions by default..

     	register(timezone, false);

     }

     /**

      * {@inheritDoc}

      */

     public final void register(final TimeZone timezone, boolean update) {

     	if (update) {

             // load any available updates for the timezone..

             timezones.put(timezone.getID(), new TimeZone(updateDefinition(timezone.getVTimeZone())));

     	}

     	else {

             timezones.put(timezone.getID(), timezone);

     	}

     }

     /**

      * {@inheritDoc}

      */

     public final void clear() {

         timezones.clear();

     }

     /**

      * {@inheritDoc}

      */

     public final TimeZone getTimeZone(final String id) {

         TimeZone timezone = (TimeZone) timezones.get(id);

         if (timezone == null) {

             timezone = (TimeZone) DEFAULT_TIMEZONES.get(id);

             if (timezone == null) {

                 // if timezone not found with identifier, try loading an alias..

                 final String alias = ALIASES.getProperty(id);

                 if (alias != null) {

                     return getTimeZone(alias);

                 }

                 else {

                     synchronized (DEFAULT_TIMEZONES) {

                     	// check again as it may be loaded now..

                     	timezone = (TimeZone) DEFAULT_TIMEZONES.get(id);

                     	if (timezone == null) {

                             try {

                                 final VTimeZone vTimeZone = loadVTimeZone(id);

                                 if (vTimeZone != null) {

                                     // XXX: temporary kludge..

                                     // ((TzId) vTimeZone.getProperties().getProperty(Property.TZID)).setValue(id);

                                     timezone = new TimeZone(vTimeZone);

                                     DEFAULT_TIMEZONES.put(timezone.getID(), timezone);

                                 }

                                 else if (CompatibilityHints.isHintEnabled(CompatibilityHints.KEY_RELAXED_PARSING)) {

                                     // strip global part of id and match on default tz..

                                     Matcher matcher = TZ_ID_SUFFIX.matcher(id);

                                     if (matcher.find()) {

                                         return getTimeZone(matcher.group());

                                     }

                                 }

                             }

                             catch (Exception e) {

                                 Log log = LogFactory.getLog(TimeZoneRegistryImpl.class);

                                 log.warn("Error occurred loading VTimeZone", e);

                             }

                     	}

                     }

                 }

             }

         }

         return timezone;

     }

     /**

      * Loads an existing VTimeZone from the classpath corresponding to the specified Java timezone.

      */

     private VTimeZone loadVTimeZone(final String id) throws IOException, ParserException {

         final URL resource = ResourceLoader.getResource(resourcePrefix + id + ".ics");

         if (resource != null) {

             final CalendarBuilder builder = new CalendarBuilder();

             final Calendar calendar = builder.build(resource.openStream());

             final VTimeZone vTimeZone = (VTimeZone) calendar.getComponent(Component.VTIMEZONE);

             // load any available updates for the timezone.. can be explicility disabled via configuration

             if (!"false".equals(Configurator.getProperty(UPDATE_ENABLED))) {

                 return updateDefinition(vTimeZone);

             }

             return vTimeZone;

         }

         return null;

     }

     /**

      * @param vTimeZone

      * @return

      */

     private VTimeZone updateDefinition(VTimeZone vTimeZone) {

         final TzUrl tzUrl = vTimeZone.getTimeZoneUrl();

         if (tzUrl != null) {

             try {

                 final CalendarBuilder builder = new CalendarBuilder();

                 final Calendar calendar = builder.build(tzUrl.getUri().toURL().openStream());

                 final VTimeZone updatedVTimeZone = (VTimeZone) calendar.getComponent(Component.VTIMEZONE);

                 if (updatedVTimeZone != null) {

                     return updatedVTimeZone;

                 }

             }

             catch (Exception e) {

                 Log log = LogFactory.getLog(TimeZoneRegistryImpl.class);

                 log.warn("Unable to retrieve updates for timezone: " + vTimeZone.getTimeZoneId().getValue(), e);

             }

         }

         return vTimeZone;

     }

 }