I18nConfigOptionsProvider.java

/**
 * Copyright (c) 2014-2017 by the respective copyright holders.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 */
package org.eclipse.smarthome.config.core.internal.i18n;

import java.net.URI;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.LinkedList;
import java.util.List;
import java.util.Locale;
import java.util.TimeZone;
import java.util.concurrent.TimeUnit;
import java.util.function.Function;
import java.util.stream.Collectors;

import org.eclipse.smarthome.config.core.ConfigOptionProvider;
import org.eclipse.smarthome.config.core.ParameterOption;
import org.osgi.service.component.annotations.Component;

/**
 * {@link ConfigOptionProvider} that provides a list of
 *
 * @author Simon Kaufmann - initial contribution and API
 * @author Erdoan Hadzhiyusein - Added time zone
 *
 */
@Component(immediate = true)
public class I18nConfigOptionsProvider implements ConfigOptionProvider {

    private static final String NO_OFFSET_FORMAT = "(GMT) %s";
    private static final String NEGATIVE_OFFSET_FORMAT = "%s (GMT%d:%02d)";
    private static final String POSITIVE_OFFSET_FORMAT = "%s (GMT+%d:%02d)";

    @Override
    public Collection<ParameterOption> getParameterOptions(URI uri, String param, Locale locale) {
        if (uri.toString().equals("system:i18n")) {
            Locale translation = locale != null ? locale : Locale.getDefault();
            switch (param) {
                case "language":
                    return getAvailable(locale,
                            l -> new ParameterOption(l.getLanguage(), l.getDisplayLanguage(translation)));
                case "region":
                    return getAvailable(locale,
                            l -> new ParameterOption(l.getCountry(), l.getDisplayCountry(translation)));
                case "variant":
                    return getAvailable(locale,
                            l -> new ParameterOption(l.getVariant(), l.getDisplayVariant(translation)));
                case "timezone":
                    Collection<ParameterOption> collection = new LinkedList<ParameterOption>();
                    String[] ids = TimeZone.getAvailableIDs();
                    List<TimeZone> timeZones = Arrays.asList(ids).stream().map(TimeZone::getTimeZone)
                            .collect(Collectors.toList());
                    Collections.sort(timeZones, (s1, s2) -> s2.getRawOffset() - s1.getRawOffset());
                    // sorting the time zones by offset
                    for (TimeZone instance : timeZones) {
                        collection.add(new ParameterOption(instance.getID(), getTimeZoneRepresentation(instance)));
                    }
                    return collection;
                default:
                    return null;
            }
        }
        return null;
    }

    private static String getTimeZoneRepresentation(TimeZone tz) {
        long hours = TimeUnit.MILLISECONDS.toHours(tz.getRawOffset());
        long minutes = TimeUnit.MILLISECONDS.toMinutes(tz.getRawOffset()) - TimeUnit.HOURS.toMinutes(hours);
        minutes = Math.abs(minutes);
        String result = "";
        if (hours > 0) {
            result = String.format(POSITIVE_OFFSET_FORMAT, tz.getID(), hours, minutes);
        } else if (hours < 0) {
            result = String.format(NEGATIVE_OFFSET_FORMAT, tz.getID(), hours, minutes);
        } else {
            result = String.format(NO_OFFSET_FORMAT, tz.getDisplayName(Locale.getDefault()));
        }
        return result;
    }

    private Collection<ParameterOption> getAvailable(Locale locale, Function<Locale, ParameterOption> mapFunction) {
        return Arrays.stream(Locale.getAvailableLocales()).map(l -> mapFunction.apply(l)).distinct()
                .sorted(Comparator.comparing(a -> a.getLabel())).collect(Collectors.toList());
    }
}