Examples with BasicTimeZone android.icu.util.BasicTimeZone used on opensource projects

Example 21 with BasicTimeZone

use of android.icu.util.BasicTimeZone in project j2objc by google.

the class IcuZoneRulesProviderTest method testTransitionsNearInstants.

/**
 * Verifies that ICU and java.time return the same transitions before and after a pre-selected
 * set of instants in time.
 */
@Test
public void testTransitionsNearInstants() {
    // An arbitrary set of instants at which to test the offsets in both implementations.
    Instant[] instants = new Instant[] { LocalDateTime.of(1900, Month.DECEMBER, 24, 12, 0).toInstant(ZoneOffset.UTC), LocalDateTime.of(1970, Month.JANUARY, 1, 2, 3).toInstant(ZoneOffset.UTC), LocalDateTime.of(1980, Month.FEBRUARY, 4, 5, 6).toInstant(ZoneOffset.UTC), LocalDateTime.of(1990, Month.MARCH, 7, 8, 9).toInstant(ZoneOffset.UTC), LocalDateTime.of(2000, Month.APRIL, 10, 11, 12).toInstant(ZoneOffset.UTC), LocalDateTime.of(2016, Month.MAY, 13, 14, 15).toInstant(ZoneOffset.UTC), LocalDateTime.of(2020, Month.JUNE, 16, 17, 18).toInstant(ZoneOffset.UTC), LocalDateTime.of(2100, Month.JULY, 19, 20, 21).toInstant(ZoneOffset.UTC), // updates don't break on the then-current date.
    Instant.now() };
    // Coincidentally this test verifies that all zones can be converted to ZoneRules and
    // don't violate any of the assumptions of IcuZoneRulesProvider.
    ZoneRules rules = ZoneRulesProvider.getRules(zoneId, false);
    BasicTimeZone timeZone = (BasicTimeZone) TimeZone.getTimeZone(zoneId);
    int[] icuOffsets = new int[2];
    for (Instant instant : instants) {
        ZoneOffset offset = rules.getOffset(instant);
        Duration daylightSavings = rules.getDaylightSavings(instant);
        timeZone.getOffset(instant.toEpochMilli(), false, icuOffsets);
        assertEquals("total offset for " + zoneId + " at " + instant, icuOffsets[1] + icuOffsets[0], offset.getTotalSeconds() * 1000);
        assertEquals("dst offset for " + zoneId + " at " + instant, icuOffsets[1], daylightSavings.toMillis());
        ZoneOffsetTransition jtTrans;
        TimeZoneTransition icuTrans;
        jtTrans = rules.nextTransition(instant);
        icuTrans = timeZone.getNextTransition(instant.toEpochMilli(), false);
        while (isIcuOnlyTransition(icuTrans)) {
            icuTrans = timeZone.getNextTransition(icuTrans.getTime(), false);
        }
        assertEquivalent(icuTrans, jtTrans);
        jtTrans = rules.previousTransition(instant);
        icuTrans = timeZone.getPreviousTransition(instant.toEpochMilli(), false);
        // Find previous "real" transition.
        while (isIcuOnlyTransition(icuTrans)) {
            icuTrans = timeZone.getPreviousTransition(icuTrans.getTime(), false);
        }
        assertEquivalent(icuTrans, jtTrans);
    }
}

Example 22 with BasicTimeZone

use of android.icu.util.BasicTimeZone in project j2objc by google.

the class IcuZoneRulesProviderTest method testAllTransitions.

/**
 * Verifies that ICU and java.time rules return the same transitions between 1900 and 2100.
 */
@Test
public void testAllTransitions() {
    final Instant start = LocalDateTime.of(1900, Month.JANUARY, 1, 12, 0).toInstant(ZoneOffset.UTC);
    // Many timezones have ongoing DST changes, so they would generate transitions endlessly.
    // Pick a far-future end date to stop comparing in that case.
    final Instant end = LocalDateTime.of(2100, Month.DECEMBER, 31, 12, 0).toInstant(ZoneOffset.UTC);
    ZoneRules rules = ZoneRulesProvider.getRules(zoneId, false);
    BasicTimeZone timeZone = (BasicTimeZone) TimeZone.getTimeZone(zoneId);
    Instant instant = start;
    while (instant.isBefore(end)) {
        ZoneOffsetTransition jtTrans;
        TimeZoneTransition icuTrans;
        jtTrans = rules.nextTransition(instant);
        icuTrans = timeZone.getNextTransition(instant.toEpochMilli(), false);
        while (isIcuOnlyTransition(icuTrans)) {
            icuTrans = timeZone.getNextTransition(icuTrans.getTime(), false);
        }
        assertEquivalent(icuTrans, jtTrans);
        if (jtTrans == null) {
            break;
        }
        instant = jtTrans.getInstant();
    }
}

Example 23 with BasicTimeZone

use of android.icu.util.BasicTimeZone in project j2objc by google.

the class IcuZoneRulesProvider method generateZoneRules.

/*
     * This implementation is only tested with BasicTimeZone objects and depends on
     * implementation details of that class:
     *
     * 0. TimeZone.getFrozenTimeZone() always returns a BasicTimeZone object.
     * 1. The first rule is always an InitialTimeZoneRule (guaranteed by spec).
     * 2. AnnualTimeZoneRules are only used as "final rules".
     * 3. The final rules are either 0 or 2 AnnualTimeZoneRules
     * 4. The final rules have endYear set to MAX_YEAR.
     * 5. Each transition generated by the rules changes either the raw offset, the total offset
     *    or both.
     * 6. There is a non-immense number of transitions for any rule before the final rules apply
     *    (enforced via the arbitrary limit defined in MAX_TRANSITIONS).
     *
     * Assumptions #5 and #6 are not strictly required for this code to work, but hold for the
     * the data and code at the time of implementation. If they were broken they would indicate
     * an incomplete understanding of how ICU TimeZoneRules are used which would probably mean that
     * this code needs to be updated.
     *
     * These assumptions are verified using the verify() method where appropriate.
     */
static ZoneRules generateZoneRules(String zoneId) {
    TimeZone timeZone = TimeZone.getFrozenTimeZone(zoneId);
    // Assumption #0
    verify(timeZone instanceof BasicTimeZone, zoneId, "Unexpected time zone class " + timeZone.getClass());
    BasicTimeZone tz = (BasicTimeZone) timeZone;
    TimeZoneRule[] rules = tz.getTimeZoneRules();
    // Assumption #1
    InitialTimeZoneRule initial = (InitialTimeZoneRule) rules[0];
    ZoneOffset baseStandardOffset = millisToOffset(initial.getRawOffset());
    ZoneOffset baseWallOffset = millisToOffset((initial.getRawOffset() + initial.getDSTSavings()));
    List<ZoneOffsetTransition> standardOffsetTransitionList = new ArrayList<>();
    List<ZoneOffsetTransition> transitionList = new ArrayList<>();
    List<ZoneOffsetTransitionRule> lastRules = new ArrayList<>();
    int preLastDstSavings = 0;
    AnnualTimeZoneRule last1 = null;
    AnnualTimeZoneRule last2 = null;
    TimeZoneTransition transition = tz.getNextTransition(Long.MIN_VALUE, false);
    int transitionCount = 1;
    // "last rules" in java.time) the "break transitionLoop" will be used to exit the loop.
    transitionLoop: while (transition != null) {
        TimeZoneRule from = transition.getFrom();
        TimeZoneRule to = transition.getTo();
        boolean hadEffect = false;
        if (from.getRawOffset() != to.getRawOffset()) {
            standardOffsetTransitionList.add(new ZoneOffsetTransition(TimeUnit.MILLISECONDS.toSeconds(transition.getTime()), millisToOffset(from.getRawOffset()), millisToOffset(to.getRawOffset())));
            hadEffect = true;
        }
        int fromTotalOffset = from.getRawOffset() + from.getDSTSavings();
        int toTotalOffset = to.getRawOffset() + to.getDSTSavings();
        if (fromTotalOffset != toTotalOffset) {
            transitionList.add(new ZoneOffsetTransition(TimeUnit.MILLISECONDS.toSeconds(transition.getTime()), millisToOffset(fromTotalOffset), millisToOffset(toTotalOffset)));
            hadEffect = true;
        }
        // Assumption #5
        verify(hadEffect, zoneId, "Transition changed neither total nor raw offset.");
        if (to instanceof AnnualTimeZoneRule) {
            // The presence of an AnnualTimeZoneRule is taken as an indication of a final rule.
            if (last1 == null) {
                preLastDstSavings = from.getDSTSavings();
                last1 = (AnnualTimeZoneRule) to;
                // Assumption #4
                verify(last1.getEndYear() == AnnualTimeZoneRule.MAX_YEAR, zoneId, "AnnualTimeZoneRule is not permanent.");
            } else {
                last2 = (AnnualTimeZoneRule) to;
                // Assumption #4
                verify(last2.getEndYear() == AnnualTimeZoneRule.MAX_YEAR, zoneId, "AnnualTimeZoneRule is not permanent.");
                // Assumption #3
                transition = tz.getNextTransition(transition.getTime(), false);
                verify(transition.getTo() == last1, zoneId, "Unexpected rule after 2 AnnualTimeZoneRules.");
                break transitionLoop;
            }
        } else {
            // Assumption #2
            verify(last1 == null, zoneId, "Unexpected rule after AnnualTimeZoneRule.");
        }
        verify(transitionCount <= MAX_TRANSITIONS, zoneId, "More than " + MAX_TRANSITIONS + " transitions.");
        transition = tz.getNextTransition(transition.getTime(), false);
        transitionCount++;
    }
    if (last1 != null) {
        // Assumption #3
        verify(last2 != null, zoneId, "Only one AnnualTimeZoneRule.");
        lastRules.add(toZoneOffsetTransitionRule(last1, preLastDstSavings));
        lastRules.add(toZoneOffsetTransitionRule(last2, last1.getDSTSavings()));
    }
    return ZoneRules.of(baseStandardOffset, baseWallOffset, standardOffsetTransitionList, transitionList, lastRules);
}