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8283681: Improve ZonedDateTime offset handling
Reviewed-by: scolebourne, naoto, rriggs
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cl4es committed Mar 25, 2022
1 parent 2600f99 commit 7bac0a878d918745ed036954cbbee590ce810c71
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Showing 5 changed files with 156 additions and 4 deletions.
@@ -584,6 +584,11 @@ public ZoneId normalized() {
return this;
}

/**
* Get the effective offset for an instant at the given epochSecond.
*/
/* package-private */ abstract ZoneOffset getOffset(long epochSecond);

//-----------------------------------------------------------------------
/**
* Checks if this time-zone ID is equal to another time-zone ID.
@@ -86,6 +86,8 @@
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

import jdk.internal.vm.annotation.Stable;

/**
* A time-zone offset from Greenwich/UTC, such as {@code +02:00}.
* <p>
@@ -168,6 +170,11 @@
* The string form of the time-zone offset.
*/
private final transient String id;
/**
* The zone rules for an offset will always return this offset. Cache it for efficiency.
*/
@Stable
private transient ZoneRules rules;

//-----------------------------------------------------------------------
/**
@@ -504,7 +511,21 @@ public String getId() {
*/
@Override
public ZoneRules getRules() {
return ZoneRules.of(this);
ZoneRules rules = this.rules;
if (rules == null) {
rules = this.rules = ZoneRules.of(this);
}
return rules;
}

@Override
public ZoneId normalized() {
return this;
}

@Override
/* package-private */ ZoneOffset getOffset(long epochSecond) {
return this;
}

//-----------------------------------------------------------------------
@@ -178,6 +178,11 @@ public ZoneRules getRules() {
return (rules != null ? rules : ZoneRulesProvider.getRules(id, false));
}

@Override
/* package-private */ ZoneOffset getOffset(long epochSecond) {
return getRules().getOffset(Instant.ofEpochSecond(epochSecond));
}

//-----------------------------------------------------------------------
/**
* Writes the object using a
@@ -452,9 +452,9 @@ public static ZonedDateTime ofInstant(LocalDateTime localDateTime, ZoneOffset of
* @throws DateTimeException if the result exceeds the supported range
*/
private static ZonedDateTime create(long epochSecond, int nanoOfSecond, ZoneId zone) {
ZoneRules rules = zone.getRules();
Instant instant = Instant.ofEpochSecond(epochSecond, nanoOfSecond); // TODO: rules should be queryable by epochSeconds
ZoneOffset offset = rules.getOffset(instant);
// nanoOfSecond is in a range that'll not affect epochSecond, validated
// by LocalDateTime.ofEpochSecond
ZoneOffset offset = zone.getOffset(epochSecond);
LocalDateTime ldt = LocalDateTime.ofEpochSecond(epochSecond, nanoOfSecond, offset);
return new ZonedDateTime(ldt, offset, zone);
}
@@ -0,0 +1,121 @@
/*
* Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code 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 General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package org.openjdk.bench.java.time;

import java.time.Duration;
import java.time.Instant;
import java.time.ZonedDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;
import java.time.temporal.ChronoUnit;

import java.util.Locale;
import java.util.Random;
import java.util.TimeZone;
import java.util.concurrent.TimeUnit;
import java.util.stream.IntStream;
import java.util.stream.Stream;

import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Measurement;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Param;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.annotations.Warmup;
import org.openjdk.jmh.infra.Blackhole;

/**
* Examine ability to perform escape analysis on expressions
* such as {@code Instant.ofEpochMilli(value).atZone(ZoneOffset.UTC).getYear()}
*/
@BenchmarkMode(Mode.Throughput)
@OutputTimeUnit(TimeUnit.MILLISECONDS)
@Warmup(iterations = 5, time = 2, timeUnit = TimeUnit.SECONDS)
@Measurement(iterations = 5, time = 2, timeUnit = TimeUnit.SECONDS)
@Fork(3)
@State(Scope.Benchmark)
public class GetYearBench {

private TimeZone UTC = TimeZone.getTimeZone("UTC");

private TimeZone LONDON = TimeZone.getTimeZone("Europe/London");

private long[] INSTANT_MILLIS;

private int[] YEARS;

@Setup
public void createInstants() {
// Various instants during the same day
final Instant loInstant = Instant.EPOCH.plus(Duration.ofDays(365*50)); // 2020-01-01
final Instant hiInstant = loInstant.plus(Duration.ofDays(1));
final long maxOffsetNanos = Duration.between(loInstant, hiInstant).toNanos();
final Random random = new Random(0);
INSTANT_MILLIS = IntStream
.range(0, 1_000)
.mapToObj(ignored -> {
final long offsetNanos = (long) Math.floor(random.nextDouble() * maxOffsetNanos);
return loInstant.plus(offsetNanos, ChronoUnit.NANOS);
})
.mapToLong(instant -> instant.toEpochMilli())
.toArray();
YEARS = new int[INSTANT_MILLIS.length];
}

@Benchmark
public int[] getYearFromMillisZoneOffset() {
for (int i = 0; i < YEARS.length; i++) {
YEARS[i] = Instant.ofEpochMilli(INSTANT_MILLIS[i]).atZone(ZoneOffset.UTC).getYear();
}
return YEARS;
}

@Benchmark
public int[] getYearFromMillisZoneRegionUTC() {
for (int i = 0; i < YEARS.length; i++) {
YEARS[i] = Instant.ofEpochMilli(INSTANT_MILLIS[i]).atZone(UTC.toZoneId()).getYear();
}
return YEARS;
}

@Benchmark
public int[] getYearFromMillisZoneRegion() {
for (int i = 0; i < YEARS.length; i++) {
YEARS[i] = Instant.ofEpochMilli(INSTANT_MILLIS[i]).atZone(LONDON.toZoneId()).getYear();
}
return YEARS;
}

@Benchmark
public int[] getYearFromMillisZoneRegionNormalized() {
for (int i = 0; i < YEARS.length; i++) {
YEARS[i] = Instant.ofEpochMilli(INSTANT_MILLIS[i]).atZone(UTC.toZoneId().normalized()).getYear();
}
return YEARS;
}
}

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