com/android/internal/telephony/TimeZoneLookupHelper.java - platform/prebuilts/fullsdk/sources/android-29 - Git at Google

 /*
  * Copyright 2017 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 com.android.internal.telephony;

 import android.text.TextUtils;

 import libcore.timezone.CountryTimeZones;
 import libcore.timezone.TimeZoneFinder;

 import java.util.Date;
 import java.util.TimeZone;

 /**
  * An interface to various time zone lookup behaviors.
  */
 // Non-final to allow mocking.
 public class TimeZoneLookupHelper {

     /**
      * The result of looking up a time zone using offset information (and possibly more).
      */
     public static final class OffsetResult {

         /** A zone that matches the supplied criteria. See also {@link #isOnlyMatch}. */
         public final String zoneId;

         /** True if there is only one matching time zone for the supplied criteria. */
         public final boolean isOnlyMatch;

         public OffsetResult(String zoneId, boolean isOnlyMatch) {
             this.zoneId = zoneId;
             this.isOnlyMatch = isOnlyMatch;
         }

         @Override
         public boolean equals(Object o) {
             if (this == o) {
                 return true;
             }
             if (o == null || getClass() != o.getClass()) {
                 return false;
             }

             OffsetResult result = (OffsetResult) o;

             if (isOnlyMatch != result.isOnlyMatch) {
                 return false;
             }
             return zoneId.equals(result.zoneId);
         }

         @Override
         public int hashCode() {
             int result = zoneId.hashCode();
             result = 31 * result + (isOnlyMatch ? 1 : 0);
             return result;
         }

         @Override
         public String toString() {
             return "Result{"
                     + "zoneId='" + zoneId + '\''
                     + ", isOnlyMatch=" + isOnlyMatch
                     + '}';
         }
     }

     /**
      * The result of looking up a time zone using country information.
      */
     public static final class CountryResult {

         /** A time zone for the country. */
         public final String zoneId;

         /**
          * True if all the time zones in the country have the same offset at {@link #whenMillis}.
          */
         public final boolean allZonesHaveSameOffset;

         /** The time associated with {@link #allZonesHaveSameOffset}. */
         public final long whenMillis;

         public CountryResult(String zoneId, boolean allZonesHaveSameOffset, long whenMillis) {
             this.zoneId = zoneId;
             this.allZonesHaveSameOffset = allZonesHaveSameOffset;
             this.whenMillis = whenMillis;
         }

         @Override
         public boolean equals(Object o) {
             if (this == o) {
                 return true;
             }
             if (o == null || getClass() != o.getClass()) {
                 return false;
             }

             CountryResult that = (CountryResult) o;

             if (allZonesHaveSameOffset != that.allZonesHaveSameOffset) {
                 return false;
             }
             if (whenMillis != that.whenMillis) {
                 return false;
             }
             return zoneId.equals(that.zoneId);
         }

         @Override
         public int hashCode() {
             int result = zoneId.hashCode();
             result = 31 * result + (allZonesHaveSameOffset ? 1 : 0);
             result = 31 * result + (int) (whenMillis ^ (whenMillis >>> 32));
             return result;
         }

         @Override
         public String toString() {
             return "CountryResult{"
                     + "zoneId='" + zoneId + '\''
                     + ", allZonesHaveSameOffset=" + allZonesHaveSameOffset
                     + ", whenMillis=" + whenMillis
                     + '}';
         }
     }

     private static final int MS_PER_HOUR = 60 * 60 * 1000;

     /** The last CountryTimeZones object retrieved. */
     private CountryTimeZones mLastCountryTimeZones;

     public TimeZoneLookupHelper() {}

     /**
      * Looks for a time zone for the supplied NITZ and country information.
      *
      * <p><em>Note:</em> When there are multiple matching zones then one of the matching candidates
      * will be returned in the result. If the current device default zone matches it will be
      * returned in preference to other candidates. This method can return {@code null} if no
      * matching time zones are found.
      */
     public OffsetResult lookupByNitzCountry(NitzData nitzData, String isoCountryCode) {
         CountryTimeZones countryTimeZones = getCountryTimeZones(isoCountryCode);
         if (countryTimeZones == null) {
             return null;
         }
         android.icu.util.TimeZone bias = android.icu.util.TimeZone.getDefault();

         CountryTimeZones.OffsetResult offsetResult = countryTimeZones.lookupByOffsetWithBias(
                 nitzData.getLocalOffsetMillis(), nitzData.isDst(),
                 nitzData.getCurrentTimeInMillis(), bias);

         if (offsetResult == null) {
             return null;
         }
         return new OffsetResult(offsetResult.mTimeZone.getID(), offsetResult.mOneMatch);
     }

     /**
      * Looks for a time zone using only information present in the supplied {@link NitzData} object.
      *
      * <p><em>Note:</em> Because multiple time zones can have the same offset / DST state at a given
      * time this process is error prone; an arbitrary match is returned when there are multiple
      * candidates. The algorithm can also return a non-exact match by assuming that the DST
      * information provided by NITZ is incorrect. This method can return {@code null} if no matching
      * time zones are found.
      */
     public OffsetResult lookupByNitz(NitzData nitzData) {
         return lookupByNitzStatic(nitzData);
     }

     /**
      * Returns a time zone ID for the country if possible. For counties that use a single time zone
      * this will provide a good choice. For countries with multiple time zones, a time zone is
      * returned if all time zones used in the country currently have the same offset (currently ==
      * according to the device's current system clock time). If this is not the case then
      * {@code null} can be returned.
      */
     public CountryResult lookupByCountry(String isoCountryCode, long whenMillis) {
         CountryTimeZones countryTimeZones = getCountryTimeZones(isoCountryCode);
         if (countryTimeZones == null) {
             // Unknown country code.
             return null;
         }
         if (countryTimeZones.getDefaultTimeZoneId() == null) {
             return null;
         }

         return new CountryResult(
                 countryTimeZones.getDefaultTimeZoneId(),
                 countryTimeZones.isDefaultOkForCountryTimeZoneDetection(whenMillis),
                 whenMillis);
     }

     /**
      * Finds a time zone using only information present in the supplied {@link NitzData} object.
      * This is a static method for use by {@link ServiceStateTracker}.
      *
      * <p><em>Note:</em> Because multiple time zones can have the same offset / DST state at a given
      * time this process is error prone; an arbitrary match is returned when there are multiple
      * candidates. The algorithm can also return a non-exact match by assuming that the DST
      * information provided by NITZ is incorrect. This method can return {@code null} if no matching
      * time zones are found.
      */
     static TimeZone guessZoneByNitzStatic(NitzData nitzData) {
         OffsetResult result = lookupByNitzStatic(nitzData);
         return result != null ? TimeZone.getTimeZone(result.zoneId) : null;
     }

     private static OffsetResult lookupByNitzStatic(NitzData nitzData) {
         int utcOffsetMillis = nitzData.getLocalOffsetMillis();
         boolean isDst = nitzData.isDst();
         long timeMillis = nitzData.getCurrentTimeInMillis();

         OffsetResult match = lookupByInstantOffsetDst(timeMillis, utcOffsetMillis, isDst);
         if (match == null) {
             // Couldn't find a proper timezone.  Perhaps the DST data is wrong.
             match = lookupByInstantOffsetDst(timeMillis, utcOffsetMillis, !isDst);
         }
         return match;
     }

     private static OffsetResult lookupByInstantOffsetDst(long timeMillis, int utcOffsetMillis,
             boolean isDst) {
         int rawOffset = utcOffsetMillis;
         if (isDst) {
             rawOffset -= MS_PER_HOUR;
         }
         String[] zones = TimeZone.getAvailableIDs(rawOffset);
         TimeZone match = null;
         Date d = new Date(timeMillis);
         boolean isOnlyMatch = true;
         for (String zone : zones) {
             TimeZone tz = TimeZone.getTimeZone(zone);
             if (tz.getOffset(timeMillis) == utcOffsetMillis && tz.inDaylightTime(d) == isDst) {
                 if (match == null) {
                     match = tz;
                 } else {
                     isOnlyMatch = false;
                     break;
                 }
             }
         }

         if (match == null) {
             return null;
         }
         return new OffsetResult(match.getID(), isOnlyMatch);
     }

     /**
      * Returns {@code true} if the supplied (lower-case) ISO country code is for a country known to
      * use a raw offset of zero from UTC at the time specified.
      */
     public boolean countryUsesUtc(String isoCountryCode, long whenMillis) {
         if (TextUtils.isEmpty(isoCountryCode)) {
             return false;
         }

         CountryTimeZones countryTimeZones = getCountryTimeZones(isoCountryCode);
         return countryTimeZones != null && countryTimeZones.hasUtcZone(whenMillis);
     }

     private CountryTimeZones getCountryTimeZones(String isoCountryCode) {
         // A single entry cache of the last CountryTimeZones object retrieved since there should
         // be strong consistency across calls.
         synchronized (this) {
             if (mLastCountryTimeZones != null) {
                 if (mLastCountryTimeZones.isForCountryCode(isoCountryCode)) {
                     return mLastCountryTimeZones;
                 }
             }

             // Perform the lookup. It's very unlikely to return null, but we won't cache null.
             CountryTimeZones countryTimeZones =
                     TimeZoneFinder.getInstance().lookupCountryTimeZones(isoCountryCode);
             if (countryTimeZones != null) {
                 mLastCountryTimeZones = countryTimeZones;
             }
             return countryTimeZones;
         }
     }
 }
	/*
	* Copyright 2017 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 com.android.internal.telephony;

	import android.text.TextUtils;

	import libcore.timezone.CountryTimeZones;
	import libcore.timezone.TimeZoneFinder;

	import java.util.Date;
	import java.util.TimeZone;

	/**
	* An interface to various time zone lookup behaviors.
	*/
	// Non-final to allow mocking.
	public class TimeZoneLookupHelper {

	/**
	* The result of looking up a time zone using offset information (and possibly more).
	*/
	public static final class OffsetResult {

	/** A zone that matches the supplied criteria. See also {@link #isOnlyMatch}. */
	public final String zoneId;

	/** True if there is only one matching time zone for the supplied criteria. */
	public final boolean isOnlyMatch;

	public OffsetResult(String zoneId, boolean isOnlyMatch) {
	this.zoneId = zoneId;
	this.isOnlyMatch = isOnlyMatch;
	}

	@Override
	public boolean equals(Object o) {
	if (this == o) {
	return true;
	}
	if (o == null \|\| getClass() != o.getClass()) {
	return false;
	}

	OffsetResult result = (OffsetResult) o;

	if (isOnlyMatch != result.isOnlyMatch) {
	return false;
	}
	return zoneId.equals(result.zoneId);
	}

	@Override
	public int hashCode() {
	int result = zoneId.hashCode();
	result = 31 * result + (isOnlyMatch ? 1 : 0);
	return result;
	}

	@Override
	public String toString() {
	return "Result{"
	+ "zoneId='" + zoneId + '\''
	+ ", isOnlyMatch=" + isOnlyMatch
	+ '}';
	}
	}

	/**
	* The result of looking up a time zone using country information.
	*/
	public static final class CountryResult {

	/** A time zone for the country. */
	public final String zoneId;

	/**
	* True if all the time zones in the country have the same offset at {@link #whenMillis}.
	*/
	public final boolean allZonesHaveSameOffset;

	/** The time associated with {@link #allZonesHaveSameOffset}. */
	public final long whenMillis;

	public CountryResult(String zoneId, boolean allZonesHaveSameOffset, long whenMillis) {
	this.zoneId = zoneId;
	this.allZonesHaveSameOffset = allZonesHaveSameOffset;
	this.whenMillis = whenMillis;
	}

	@Override
	public boolean equals(Object o) {
	if (this == o) {
	return true;
	}
	if (o == null \|\| getClass() != o.getClass()) {
	return false;
	}

	CountryResult that = (CountryResult) o;

	if (allZonesHaveSameOffset != that.allZonesHaveSameOffset) {
	return false;
	}
	if (whenMillis != that.whenMillis) {
	return false;
	}
	return zoneId.equals(that.zoneId);
	}

	@Override
	public int hashCode() {
	int result = zoneId.hashCode();
	result = 31 * result + (allZonesHaveSameOffset ? 1 : 0);
	result = 31 * result + (int) (whenMillis ^ (whenMillis >>> 32));
	return result;
	}

	@Override
	public String toString() {
	return "CountryResult{"
	+ "zoneId='" + zoneId + '\''
	+ ", allZonesHaveSameOffset=" + allZonesHaveSameOffset
	+ ", whenMillis=" + whenMillis
	+ '}';
	}
	}

	private static final int MS_PER_HOUR = 60 * 60 * 1000;

	/** The last CountryTimeZones object retrieved. */
	private CountryTimeZones mLastCountryTimeZones;

	public TimeZoneLookupHelper() {}

	/**
	* Looks for a time zone for the supplied NITZ and country information.
	*
	* <p><em>Note:</em> When there are multiple matching zones then one of the matching candidates
	* will be returned in the result. If the current device default zone matches it will be
	* returned in preference to other candidates. This method can return {@code null} if no
	* matching time zones are found.
	*/
	public OffsetResult lookupByNitzCountry(NitzData nitzData, String isoCountryCode) {
	CountryTimeZones countryTimeZones = getCountryTimeZones(isoCountryCode);
	if (countryTimeZones == null) {
	return null;
	}
	android.icu.util.TimeZone bias = android.icu.util.TimeZone.getDefault();

	CountryTimeZones.OffsetResult offsetResult = countryTimeZones.lookupByOffsetWithBias(
	nitzData.getLocalOffsetMillis(), nitzData.isDst(),
	nitzData.getCurrentTimeInMillis(), bias);

	if (offsetResult == null) {
	return null;
	}
	return new OffsetResult(offsetResult.mTimeZone.getID(), offsetResult.mOneMatch);
	}

	/**
	* Looks for a time zone using only information present in the supplied {@link NitzData} object.
	*
	* <p><em>Note:</em> Because multiple time zones can have the same offset / DST state at a given
	* time this process is error prone; an arbitrary match is returned when there are multiple
	* candidates. The algorithm can also return a non-exact match by assuming that the DST
	* information provided by NITZ is incorrect. This method can return {@code null} if no matching
	* time zones are found.
	*/
	public OffsetResult lookupByNitz(NitzData nitzData) {
	return lookupByNitzStatic(nitzData);
	}

	/**
	* Returns a time zone ID for the country if possible. For counties that use a single time zone
	* this will provide a good choice. For countries with multiple time zones, a time zone is
	* returned if all time zones used in the country currently have the same offset (currently ==
	* according to the device's current system clock time). If this is not the case then
	* {@code null} can be returned.
	*/
	public CountryResult lookupByCountry(String isoCountryCode, long whenMillis) {
	CountryTimeZones countryTimeZones = getCountryTimeZones(isoCountryCode);
	if (countryTimeZones == null) {
	// Unknown country code.
	return null;
	}
	if (countryTimeZones.getDefaultTimeZoneId() == null) {
	return null;
	}

	return new CountryResult(
	countryTimeZones.getDefaultTimeZoneId(),
	countryTimeZones.isDefaultOkForCountryTimeZoneDetection(whenMillis),
	whenMillis);
	}

	/**
	* Finds a time zone using only information present in the supplied {@link NitzData} object.
	* This is a static method for use by {@link ServiceStateTracker}.
	*
	* <p><em>Note:</em> Because multiple time zones can have the same offset / DST state at a given
	* time this process is error prone; an arbitrary match is returned when there are multiple
	* candidates. The algorithm can also return a non-exact match by assuming that the DST
	* information provided by NITZ is incorrect. This method can return {@code null} if no matching
	* time zones are found.
	*/
	static TimeZone guessZoneByNitzStatic(NitzData nitzData) {
	OffsetResult result = lookupByNitzStatic(nitzData);
	return result != null ? TimeZone.getTimeZone(result.zoneId) : null;
	}

	private static OffsetResult lookupByNitzStatic(NitzData nitzData) {
	int utcOffsetMillis = nitzData.getLocalOffsetMillis();
	boolean isDst = nitzData.isDst();
	long timeMillis = nitzData.getCurrentTimeInMillis();

	OffsetResult match = lookupByInstantOffsetDst(timeMillis, utcOffsetMillis, isDst);
	if (match == null) {
	// Couldn't find a proper timezone. Perhaps the DST data is wrong.
	match = lookupByInstantOffsetDst(timeMillis, utcOffsetMillis, !isDst);
	}
	return match;
	}

	private static OffsetResult lookupByInstantOffsetDst(long timeMillis, int utcOffsetMillis,
	boolean isDst) {
	int rawOffset = utcOffsetMillis;
	if (isDst) {
	rawOffset -= MS_PER_HOUR;
	}
	String[] zones = TimeZone.getAvailableIDs(rawOffset);
	TimeZone match = null;
	Date d = new Date(timeMillis);
	boolean isOnlyMatch = true;
	for (String zone : zones) {
	TimeZone tz = TimeZone.getTimeZone(zone);
	if (tz.getOffset(timeMillis) == utcOffsetMillis && tz.inDaylightTime(d) == isDst) {
	if (match == null) {
	match = tz;
	} else {
	isOnlyMatch = false;
	break;
	}
	}
	}

	if (match == null) {
	return null;
	}
	return new OffsetResult(match.getID(), isOnlyMatch);
	}

	/**
	* Returns {@code true} if the supplied (lower-case) ISO country code is for a country known to
	* use a raw offset of zero from UTC at the time specified.
	*/
	public boolean countryUsesUtc(String isoCountryCode, long whenMillis) {
	if (TextUtils.isEmpty(isoCountryCode)) {
	return false;
	}

	CountryTimeZones countryTimeZones = getCountryTimeZones(isoCountryCode);
	return countryTimeZones != null && countryTimeZones.hasUtcZone(whenMillis);
	}

	private CountryTimeZones getCountryTimeZones(String isoCountryCode) {
	// A single entry cache of the last CountryTimeZones object retrieved since there should
	// be strong consistency across calls.
	synchronized (this) {
	if (mLastCountryTimeZones != null) {
	if (mLastCountryTimeZones.isForCountryCode(isoCountryCode)) {
	return mLastCountryTimeZones;
	}
	}

	// Perform the lookup. It's very unlikely to return null, but we won't cache null.
	CountryTimeZones countryTimeZones =
	TimeZoneFinder.getInstance().lookupCountryTimeZones(isoCountryCode);
	if (countryTimeZones != null) {
	mLastCountryTimeZones = countryTimeZones;
	}
	return countryTimeZones;
	}
	}
	}