org.obm.push.protocol.data.ASTimeZoneConverterImpl.java Source code

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Here is the source code for org.obm.push.protocol.data.ASTimeZoneConverterImpl.java

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/* ***** BEGIN LICENSE BLOCK *****
 * 
 * Copyright (C) 2011-2014  Linagora
 *
 * This program is free software: you can redistribute it and/or 
 * modify it under the terms of the GNU Affero General Public License as 
 * published by the Free Software Foundation, either version 3 of the 
 * License, or (at your option) any later version, provided you comply 
 * with the Additional Terms applicable for OBM connector by Linagora 
 * pursuant to Section 7 of the GNU Affero General Public License, 
 * subsections (b), (c), and (e), pursuant to which you must notably (i) retain 
 * the Message sent thanks to OBM, Free Communication by Linagora? 
 * signature notice appended to any and all outbound messages 
 * (notably e-mail and meeting requests), (ii) retain all hypertext links between 
 * OBM and obm.org, as well as between Linagora and linagora.com, and (iii) refrain 
 * from infringing Linagora intellectual property rights over its trademarks 
 * and commercial brands. Other Additional Terms apply, 
 * see <http://www.linagora.com/licenses/> for more details. 
 *
 * This program is distributed in the hope that it will be useful, 
 * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License 
 * for more details. 
 *
 * You should have received a copy of the GNU Affero General Public License 
 * and its applicable Additional Terms for OBM along with this program. If not, 
 * see <http://www.gnu.org/licenses/> for the GNU Affero General Public License version 3 
 * and <http://www.linagora.com/licenses/> for the Additional Terms applicable to 
 * OBM connectors. 
 * 
 * ***** END LICENSE BLOCK ***** */
package org.obm.push.protocol.data;

import java.util.Arrays;
import java.util.Collection;
import java.util.Comparator;
import java.util.Locale;
import java.util.TimeZone;

import org.joda.time.DateTimeZone;
import org.obm.push.protocol.bean.ASTimeZone;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Optional;
import com.google.common.base.Predicates;
import com.google.common.collect.FluentIterable;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableList.Builder;
import com.google.common.collect.Lists;
import com.google.inject.Inject;
import com.google.inject.Singleton;

@Singleton
public class ASTimeZoneConverterImpl implements ASTimeZoneConverter {

    private static final String UTC = "UTC";

    private final class TimeZoneComparator implements Comparator<String> {
        @Override
        public int compare(String left, String right) {
            if (TIME_ZONE_PREFERENCES.contains(right) && !TIME_ZONE_PREFERENCES.contains(left)) {
                return 1;
            } else if (!TIME_ZONE_PREFERENCES.contains(right) && TIME_ZONE_PREFERENCES.contains(left)) {
                return -1;
            } else {
                return left.compareTo(right);
            }
        }
    }

    @VisibleForTesting
    static final Collection<String> TIME_ZONE_PREFERENCES = Lists.newArrayList(UTC, "Europe/Paris", "Europe/London",
            "America/New_York", "America/Los_Angeles", "Australia/Sydney");

    private final TimeZoneConverter timeZoneConverter;

    @Inject
    @VisibleForTesting
    ASTimeZoneConverterImpl(TimeZoneConverter timeZoneConverter) {
        this.timeZoneConverter = timeZoneConverter;
    }

    @Override
    public Optional<TimeZone> convert(ASTimeZone asTimeZone) {
        return FluentIterable.from(matchJavaTimeZones(asTimeZone)).first();
    }

    @VisibleForTesting
    Iterable<TimeZone> matchJavaTimeZones(ASTimeZone asTimeZone) {
        if (asTimeZone.useDaylightTime()) {
            return findTimeZones(asTimeZone);
        }
        return getTimeZonesWithoutDST(asTimeZone);
    }

    private Iterable<String> getAvailableTimeZoneIDs(ASTimeZone asTimeZone) {
        int rawOffset = -1 * toMillis(asTimeZone.getBias());
        String[] availableIDs = TimeZone.getAvailableIDs(rawOffset);
        return FluentIterable.from(Arrays.asList(availableIDs))
                .filter(Predicates.in(DateTimeZone.getAvailableIDs())).toSortedSet(new TimeZoneComparator());
    }

    private int toMillis(int minutes) {
        return minutes * 60 * 1000;
    }

    private Iterable<TimeZone> findTimeZones(ASTimeZone asTimeZone) {
        Builder<TimeZone> timezones = ImmutableList.builder();
        for (String availableID : getAvailableTimeZoneIDs(asTimeZone)) {
            TimeZone timeZone = TimeZone.getTimeZone(availableID);
            ASTimeZone timeZoneConverted = timeZoneConverter.convert(timeZone, Locale.US);
            if (timeZoneConverted.equalsDiscardingNames(asTimeZone)) {
                timezones.add(timeZone);
            }
        }
        return timezones.build();
    }

    private Iterable<TimeZone> getTimeZonesWithoutDST(ASTimeZone asTimeZone) {
        Builder<TimeZone> timezones = ImmutableList.builder();
        for (String availableID : getAvailableTimeZoneIDs(asTimeZone)) {
            TimeZone timeZone = TimeZone.getTimeZone(availableID);
            if (!timeZone.useDaylightTime()) {
                timezones.add(timeZone);
            }
        }
        return timezones.build();
    }
}