| /* |
| * Copyright (C) 2006 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package android.util; |
| |
| import android.content.res.Resources; |
| import android.content.res.XmlResourceParser; |
| |
| import org.apache.harmony.luni.internal.util.ZoneInfoDB; |
| import org.xmlpull.v1.XmlPullParser; |
| import org.xmlpull.v1.XmlPullParserException; |
| |
| import java.io.IOException; |
| import java.util.TimeZone; |
| import java.util.Date; |
| |
| import com.android.internal.util.XmlUtils; |
| |
| /** |
| * A class containing utility methods related to time zones. |
| */ |
| public class TimeUtils { |
| private static final String TAG = "TimeUtils"; |
| |
| /** |
| * Tries to return a time zone that would have had the specified offset |
| * and DST value at the specified moment in the specified country. |
| * Returns null if no suitable zone could be found. |
| */ |
| public static TimeZone getTimeZone(int offset, boolean dst, long when, String country) { |
| if (country == null) { |
| return null; |
| } |
| |
| TimeZone best = null; |
| |
| Resources r = Resources.getSystem(); |
| XmlResourceParser parser = r.getXml(com.android.internal.R.xml.time_zones_by_country); |
| Date d = new Date(when); |
| |
| TimeZone current = TimeZone.getDefault(); |
| String currentName = current.getID(); |
| int currentOffset = current.getOffset(when); |
| boolean currentDst = current.inDaylightTime(d); |
| |
| try { |
| XmlUtils.beginDocument(parser, "timezones"); |
| |
| while (true) { |
| XmlUtils.nextElement(parser); |
| |
| String element = parser.getName(); |
| if (element == null || !(element.equals("timezone"))) { |
| break; |
| } |
| |
| String code = parser.getAttributeValue(null, "code"); |
| |
| if (country.equals(code)) { |
| if (parser.next() == XmlPullParser.TEXT) { |
| String maybe = parser.getText(); |
| |
| // If the current time zone is from the right country |
| // and meets the other known properties, keep it |
| // instead of changing to another one. |
| |
| if (maybe.equals(currentName)) { |
| if (currentOffset == offset && currentDst == dst) { |
| return current; |
| } |
| } |
| |
| // Otherwise, take the first zone from the right |
| // country that has the correct current offset and DST. |
| // (Keep iterating instead of returning in case we |
| // haven't encountered the current time zone yet.) |
| |
| if (best == null) { |
| TimeZone tz = TimeZone.getTimeZone(maybe); |
| |
| if (tz.getOffset(when) == offset && |
| tz.inDaylightTime(d) == dst) { |
| best = tz; |
| } |
| } |
| } |
| } |
| } |
| } catch (XmlPullParserException e) { |
| Log.e(TAG, "Got exception while getting preferred time zone.", e); |
| } catch (IOException e) { |
| Log.e(TAG, "Got exception while getting preferred time zone.", e); |
| } finally { |
| parser.close(); |
| } |
| |
| return best; |
| } |
| |
| /** |
| * Returns a String indicating the version of the time zone database currently |
| * in use. The format of the string is dependent on the underlying time zone |
| * database implementation, but will typically contain the year in which the database |
| * was updated plus a letter from a to z indicating changes made within that year. |
| * |
| * <p>Time zone database updates should be expected to occur periodically due to |
| * political and legal changes that cannot be anticipated in advance. Therefore, |
| * when computing the UTC time for a future event, applications should be aware that |
| * the results may differ following a time zone database update. This method allows |
| * applications to detect that a database change has occurred, and to recalculate any |
| * cached times accordingly. |
| * |
| * <p>The time zone database may be assumed to change only when the device runtime |
| * is restarted. Therefore, it is not necessary to re-query the database version |
| * during the lifetime of an activity. |
| */ |
| public static String getTimeZoneDatabaseVersion() { |
| return ZoneInfoDB.getVersion(); |
| } |
| } |